Two problems initially: one tube was burned out (with all the filaments in series); I had a spare. Secondly, the set originally had a selenium diode, that had been replaced in the past with a silicon diode and a dropping resistor, possibly 100 ohms. The added dropping resistor was in bad physical condition and wide open. We shunted the open dropping resistor. Still no joy, even though the tubes were lighted and the audio section was OK, with a hum.

Then we checked the B+ at each tube. All were OK, except for the IF amp tube, which was way low. We went back to double-check that tube's B+, and in the process of touching probes to the plate and cathode pins, the radio came alive - sounded good, picking up distant broadcast stations. Must have been a loose connection, right?

Then we went back to wiggle that tube's socket pins with a small screwdriver (mistake) to see what might be loose. In the process, we shorted either B+ or 120V AC (more likely, I think) to the filament string. Audible and visual spark. All five tubes' filaments were burned out. (Ouch, but they're not all that rare.)

As luck would have it, Paul had a replacement set of tubes on order from RadioDaze, so soon he will be able to try to get this back in operation.

He's understandably worried that maybe we damaged something in the radio. Time will tell, but I doubt it.

Comments?
Doug

marv

:Paul G. and I got together today at my house to go through his completely dead Philco AC/DC portable - wood grill and very nice leather case.
:
:Two problems initially: one tube was burned out (with all the filaments in series); I had a spare. Secondly, the set originally had a selenium diode, that had been replaced in the past with a silicon diode and a dropping resistor, possibly 100 ohms. The added dropping resistor was in bad physical condition and wide open. We shunted the open dropping resistor. Still no joy, even though the tubes were lighted and the audio section was OK, with a hum.
:
:Then we checked the B+ at each tube. All were OK, except for the IF amp tube, which was way low. We went back to double-check that tube's B+, and in the process of touching probes to the plate and cathode pins, the radio came alive - sounded good, picking up distant broadcast stations. Must have been a loose connection, right?
:
:Then we went back to wiggle that tube's socket pins with a small screwdriver (mistake) to see what might be loose. In the process, we shorted either B+ or 120V AC (more likely, I think) to the filament string. Audible and visual spark. All five tubes' filaments were burned out. (Ouch, but they're not all that rare.)
:
:As luck would have it, Paul had a replacement set of tubes on order from RadioDaze, so soon he will be able to try to get this back in operation.
:
:He's understandably worried that maybe we damaged something in the radio. Time will tell, but I doubt it.
:
:Comments?
:Doug

Two weak arguments in my defense. The wiring on those post-war portables is very tight, and easy to make a mistake. Secondly, it was Paul who did the wiggling and the shorting. (Unfortuately, it was I who handed him the screwdriver, and told him to use it for wiggling connections.)

The next time I encounter a swizzle stick, I will save it.

Seriously, do you have any comment on our troubleshooting approach, other than the screwdriver mistake?
Doug

:Hmmmm! This time of year, surprised you didn't use a "swizzle stik" instead of the screwdriver. I keep an ample supply of screwdriver swizzle stiks (plastic)on my bench at all times, but having switched to the red, only use them on special occassions for testing radios.
:
:
:marv
:
::Paul G. and I got together today at my house to go through his completely dead Philco AC/DC portable - wood grill and very nice leather case.
::
::Two problems initially: one tube was burned out (with all the filaments in series); I had a spare. Secondly, the set originally had a selenium diode, that had been replaced in the past with a silicon diode and a dropping resistor, possibly 100 ohms. The added dropping resistor was in bad physical condition and wide open. We shunted the open dropping resistor. Still no joy, even though the tubes were lighted and the audio section was OK, with a hum.
::
::Then we checked the B+ at each tube. All were OK, except for the IF amp tube, which was way low. We went back to double-check that tube's B+, and in the process of touching probes to the plate and cathode pins, the radio came alive - sounded good, picking up distant broadcast stations. Must have been a loose connection, right?
::
::Then we went back to wiggle that tube's socket pins with a small screwdriver (mistake) to see what might be loose. In the process, we shorted either B+ or 120V AC (more likely, I think) to the filament string. Audible and visual spark. All five tubes' filaments were burned out. (Ouch, but they're not all that rare.)
::
::As luck would have it, Paul had a replacement set of tubes on order from RadioDaze, so soon he will be able to try to get this back in operation.
::
::He's understandably worried that maybe we damaged something in the radio. Time will tell, but I doubt it.
::
::Comments?
::Doug

I use 1/8-inch or so diameter dowel stock cut to various lengths. I sanded one end to a point for probing. I actually boiled them in linseed oil to try to make them stronger. They work pretty well and a dowel about three feet long was less than a buck. I even have some I filed the end down until it looked like a flat blade screwdriver for adjusting those pesky ungrounded trimmers.

Radiodoc
**********

:Marv, how right you are!
:
:Two weak arguments in my defense. The wiring on those post-war portables is very tight, and easy to make a mistake. Secondly, it was Paul who did the wiggling and the shorting. (Unfortuately, it was I who handed him the screwdriver, and told him to use it for wiggling connections.)
:
:The next time I encounter a swizzle stick, I will save it.
:
:Seriously, do you have any comment on our troubleshooting approach, other than the screwdriver mistake?
:Doug
:
:
::Hmmmm! This time of year, surprised you didn't use a "swizzle stik" instead of the screwdriver. I keep an ample supply of screwdriver swizzle stiks (plastic)on my bench at all times, but having switched to the red, only use them on special occassions for testing radios.
::
::
::marv
::
:::Paul G. and I got together today at my house to go through his completely dead Philco AC/DC portable - wood grill and very nice leather case.
:::
:::Two problems initially: one tube was burned out (with all the filaments in series); I had a spare. Secondly, the set originally had a selenium diode, that had been replaced in the past with a silicon diode and a dropping resistor, possibly 100 ohms. The added dropping resistor was in bad physical condition and wide open. We shunted the open dropping resistor. Still no joy, even though the tubes were lighted and the audio section was OK, with a hum.
:::
:::Then we checked the B+ at each tube. All were OK, except for the IF amp tube, which was way low. We went back to double-check that tube's B+, and in the process of touching probes to the plate and cathode pins, the radio came alive - sounded good, picking up distant broadcast stations. Must have been a loose connection, right?
:::
:::Then we went back to wiggle that tube's socket pins with a small screwdriver (mistake) to see what might be loose. In the process, we shorted either B+ or 120V AC (more likely, I think) to the filament string. Audible and visual spark. All five tubes' filaments were burned out. (Ouch, but they're not all that rare.)
:::
:::As luck would have it, Paul had a replacement set of tubes on order from RadioDaze, so soon he will be able to try to get this back in operation.
:::
:::He's understandably worried that maybe we damaged something in the radio. Time will tell, but I doubt it.
:::
:::Comments?
:::Doug

Paul

:Doug,
:
:I use 1/8-inch or so diameter dowel stock cut to various lengths. I sanded one end to a point for probing. I actually boiled them in linseed oil to try to make them stronger. They work pretty well and a dowel about three feet long was less than a buck. I even have some I filed the end down until it looked like a flat blade screwdriver for adjusting those pesky ungrounded trimmers.
:
:Radiodoc
:**********
:
:
::Marv, how right you are!
::
::Two weak arguments in my defense. The wiring on those post-war portables is very tight, and easy to make a mistake. Secondly, it was Paul who did the wiggling and the shorting. (Unfortuately, it was I who handed him the screwdriver, and told him to use it for wiggling connections.)
::
::The next time I encounter a swizzle stick, I will save it.
::
::Seriously, do you have any comment on our troubleshooting approach, other than the screwdriver mistake?
::Doug
::
::
:::Hmmmm! This time of year, surprised you didn't use a "swizzle stik" instead of the screwdriver. I keep an ample supply of screwdriver swizzle stiks (plastic)on my bench at all times, but having switched to the red, only use them on special occassions for testing radios.
:::
:::
:::marv
:::
::::Paul G. and I got together today at my house to go through his completely dead Philco AC/DC portable - wood grill and very nice leather case.
::::
::::Two problems initially: one tube was burned out (with all the filaments in series); I had a spare. Secondly, the set originally had a selenium diode, that had been replaced in the past with a silicon diode and a dropping resistor, possibly 100 ohms. The added dropping resistor was in bad physical condition and wide open. We shunted the open dropping resistor. Still no joy, even though the tubes were lighted and the audio section was OK, with a hum.
::::
::::Then we checked the B+ at each tube. All were OK, except for the IF amp tube, which was way low. We went back to double-check that tube's B+, and in the process of touching probes to the plate and cathode pins, the radio came alive - sounded good, picking up distant broadcast stations. Must have been a loose connection, right?
::::
::::Then we went back to wiggle that tube's socket pins with a small screwdriver (mistake) to see what might be loose. In the process, we shorted either B+ or 120V AC (more likely, I think) to the filament string. Audible and visual spark. All five tubes' filaments were burned out. (Ouch, but they're not all that rare.)
::::
::::As luck would have it, Paul had a replacement set of tubes on order from RadioDaze, so soon he will be able to try to get this back in operation.
::::
::::He's understandably worried that maybe we damaged something in the radio. Time will tell, but I doubt it.
::::
::::Comments?
::::Doug

All, There are also bamboo sticks you can buy at party stores that (I guess) are really swizzle sticks, but they are very hard and strong, and can be made into probes, screwdrivers, etc. No metal around live circuits!!!!! Or am I now preaching to the choir???
Lewis

marv

:Marv, how right you are!
:
:Two weak arguments in my defense. The wiring on those post-war portables is very tight, and easy to make a mistake. Secondly, it was Paul who did the wiggling and the shorting. (Unfortuately, it was I who handed him the screwdriver, and told him to use it for wiggling connections.)
:
:The next time I encounter a swizzle stick, I will save it.
:
:Seriously, do you have any comment on our troubleshooting approach, other than the screwdriver mistake?
:Doug
:
:
::Hmmmm! This time of year, surprised you didn't use a "swizzle stik" instead of the screwdriver. I keep an ample supply of screwdriver swizzle stiks (plastic)on my bench at all times, but having switched to the red, only use them on special occassions for testing radios.
::
::
::marv
::
:::Paul G. and I got together today at my house to go through his completely dead Philco AC/DC portable - wood grill and very nice leather case.
:::
:::Two problems initially: one tube was burned out (with all the filaments in series); I had a spare. Secondly, the set originally had a selenium diode, that had been replaced in the past with a silicon diode and a dropping resistor, possibly 100 ohms. The added dropping resistor was in bad physical condition and wide open. We shunted the open dropping resistor. Still no joy, even though the tubes were lighted and the audio section was OK, with a hum.
:::
:::Then we checked the B+ at each tube. All were OK, except for the IF amp tube, which was way low. We went back to double-check that tube's B+, and in the process of touching probes to the plate and cathode pins, the radio came alive - sounded good, picking up distant broadcast stations. Must have been a loose connection, right?
:::
:::Then we went back to wiggle that tube's socket pins with a small screwdriver (mistake) to see what might be loose. In the process, we shorted either B+ or 120V AC (more likely, I think) to the filament string. Audible and visual spark. All five tubes' filaments were burned out. (Ouch, but they're not all that rare.)
:::
:::As luck would have it, Paul had a replacement set of tubes on order from RadioDaze, so soon he will be able to try to get this back in operation.
:::
:::He's understandably worried that maybe we damaged something in the radio. Time will tell, but I doubt it.
:::
:::Comments?
:::Doug

I wonder what the chances were of your I.F. tube having its 1st grid floating in that tube socket, thereby being unbiased and pulling
your
B+ voltage readings on that stage down somewhat, UNTIL you made tube socket connectivity, whereupon the radio blasted

to life again.




73's de Edd

:Doug,
:Well, upside down I suppose the tube socket is easy prey, but of course I would have wiggled the tubes individually to find the most likely culprit, then gone on from there. Keep a couple wood pencils on the bench, but purchase some of those slide on rubber erasers for the lead end, and don't sharpen it or stick the lead end into the electronics without the eraser in place. Graphite (read resistor) is conductive. Both ends can be used for plucking around and the big eraser is great for locating microphonic tubes.
:
:marv
:
::Marv, how right you are!
::
::Two weak arguments in my defense. The wiring on those post-war portables is very tight, and easy to make a mistake. Secondly, it was Paul who did the wiggling and the shorting. (Unfortuately, it was I who handed him the screwdriver, and told him to use it for wiggling connections.)
::
::The next time I encounter a swizzle stick, I will save it.
::
::Seriously, do you have any comment on our troubleshooting approach, other than the screwdriver mistake?
::Doug
::
::
:::Hmmmm! This time of year, surprised you didn't use a "swizzle stik" instead of the screwdriver. I keep an ample supply of screwdriver swizzle stiks (plastic)on my bench at all times, but having switched to the red, only use them on special occassions for testing radios.
:::
:::
:::marv
:::
::::Paul G. and I got together today at my house to go through his completely dead Philco AC/DC portable - wood grill and very nice leather case.
::::
::::Two problems initially: one tube was burned out (with all the filaments in series); I had a spare. Secondly, the set originally had a selenium diode, that had been replaced in the past with a silicon diode and a dropping resistor, possibly 100 ohms. The added dropping resistor was in bad physical condition and wide open. We shunted the open dropping resistor. Still no joy, even though the tubes were lighted and the audio section was OK, with a hum.
::::
::::Then we checked the B+ at each tube. All were OK, except for the IF amp tube, which was way low. We went back to double-check that tube's B+, and in the process of touching probes to the plate and cathode pins, the radio came alive - sounded good, picking up distant broadcast stations. Must have been a loose connection, right?
::::
::::Then we went back to wiggle that tube's socket pins with a small screwdriver (mistake) to see what might be loose. In the process, we shorted either B+ or 120V AC (more likely, I think) to the filament string. Audible and visual spark. All five tubes' filaments were burned out. (Ouch, but they're not all that rare.)
::::
::::As luck would have it, Paul had a replacement set of tubes on order from RadioDaze, so soon he will be able to try to get this back in operation.
::::
::::He's understandably worried that maybe we damaged something in the radio. Time will tell, but I doubt it.
::::
::::Comments?
::::Doug

But here is why I think your theory may be correct: when we first measured the low voltage on the plate pin of the tube's socket, we also backed up and measured the B+ on the primary of the 2nd IF xfmr winding. It was way low, too. So it couldn't have been a bad connection at the plate pin's socket. I remember thinking that the problem must be upstream of the IF xfmr winding, but didn't think of voltage drag-down. Your theory may explain our observation.

When Paul touched, the second time, what was supposedly the plate-pin connection with the DMM probe and the radio came to life - maybe we were mistakenly on the grid pin or maybe the force on the plate pin somehow translated to the grid pin.

I didn't write down all the other tubes' plate voltages (they were reasonable), but I think they may have been a tad low, too, particularly in relation to the filament voltages, which were OK. Again, that would seem to be in favor of your theory.

As to your Philco tube socket theory, I just don't remember what the socketw were like. Paul has the set and can check.

Paul, you need to clean all the socket connections for the IF tube and, if necessary, use Edd's suggestion for improving pin tension.
Doug

:
:
:
:
:I wonder what the chances are of that Peel-Co chassis having using the two sheet wafer sockets?
:
:As per:
:
:
:
:The first generation of those used the contacts pin construction of folding the socket pins metal over into a triangle configuration
:
:so that contact was make only by the VERY small area of the two 180 deg opposing rectangular contacts….. pressing into the
:
:individual tube pin that protruded in between them. PLUS there was not a whole lot of tensioning that was provided, with time the pin
:
:could float between the opposing contacts.
:
:Later on, they changed and made a circular forming of the contacts so that they engaged more area of the tube pin , thus giving
:
:more surface contact area.
:
:
:I remember getting those old sockets running in a pinch, until replacement could be done later, by initially pulling the tube and using a std
:
:screwdriver (ooops…look out there ! ) to press opposing contacts together to make them touch, thus giving a one shot
:
:re tensioning of all of the pins and then plugging the tube back in.
:
:
:
:I wonder what the chances were of your I.F. tube having its 1st grid floating in that tube socket, thereby being unbiased and pulling
:your
: B+ voltage readings on that stage down somewhat, UNTIL you made tube socket connectivity, whereupon the radio blasted
:
:to life again.
:

:
:
:
:73's de Edd
:
:
:

I would have to agree. Doug, do you remember how I had remarked that some of the pins on the IF tube socket seemed loose? There are 3 in particular that are really dodgy....2,3, & 7. No other sockets have any play in the pins...those mentioned on the IF socket can be wiggled quite freely. I'll do a tensioning tomorrow, while I wait with bated breath for my tube line-up, which should arrive on Monday. Thanks to both of you!

Paul

:Edd, I like your idea of the IF amp tube's grid getting unbiased and dragging down the B+ on that stage. But when we first measured the plate voltage, it was only about 3.5V, as I recall, and we were expecting 80V; that a pretty big drag-down: http://www.nostalgiaair.org/PagesByModel/774/M0013774.pdf
:
:But here is why I think your theory may be correct: when we first measured the low voltage on the plate pin of the tube's socket, we also backed up and measured the B+ on the primary of the 2nd IF xfmr winding. It was way low, too. So it couldn't have been a bad connection at the plate pin's socket. I remember thinking that the problem must be upstream of the IF xfmr winding, but didn't think of voltage drag-down. Your theory may explain our observation.
:
:When Paul touched, the second time, what was supposedly the plate-pin connection with the DMM probe and the radio came to life - maybe we were mistakenly on the grid pin or maybe the force on the plate pin somehow translated to the grid pin.
:
:I didn't write down all the other tubes' plate voltages (they were reasonable), but I think they may have been a tad low, too, particularly in relation to the filament voltages, which were OK. Again, that would seem to be in favor of your theory.
:
:As to your Philco tube socket theory, I just don't remember what the socketw were like. Paul has the set and can check.
:
:Paul, you need to clean all the socket connections for the IF tube and, if necessary, use Edd's suggestion for improving pin tension.
:Doug
:
::
::
::
::
::I wonder what the chances are of that Peel-Co chassis having using the two sheet wafer sockets?
::
::As per:
::
::
::
::The first generation of those used the contacts pin construction of folding the socket pins metal over into a triangle configuration
::
::so that contact was make only by the VERY small area of the two 180 deg opposing rectangular contacts….. pressing into the
::
::individual tube pin that protruded in between them. PLUS there was not a whole lot of tensioning that was provided, with time the pin
::
::could float between the opposing contacts.
::
::Later on, they changed and made a circular forming of the contacts so that they engaged more area of the tube pin , thus giving
::
::more surface contact area.
::
::
::I remember getting those old sockets running in a pinch, until replacement could be done later, by initially pulling the tube and using a std
::
::screwdriver (ooops…look out there ! ) to press opposing contacts together to make them touch, thus giving a one shot
::
::re tensioning of all of the pins and then plugging the tube back in.
::
::
::
::I wonder what the chances were of your I.F. tube having its 1st grid floating in that tube socket, thereby being unbiased and pulling
::your
:: B+ voltage readings on that stage down somewhat, UNTIL you made tube socket connectivity, whereupon the radio blasted
::
::to life again.
::
:
:
::
::
::
::73's de Edd
::
::
::
:

I've got another question. The bottom left of the schematics shows the filament chain, all being connected to 1 & 7 of the sockets. In the main portion of the schematics, the filamnets connections are shown as 1-5 (for pin 1). Am I correct in assuming that either pin 1 or 5 is where the connection is made, as there is NO connection to pin 1 on the IF tube socket, but there is a connection to pin 5, and damn if I can trace the wire in the cramped chassis. The must be correct assumption, or else the radio wouldn't work at all, right?

:Edd, I like your idea of the IF amp tube's grid getting unbiased and dragging down the B+ on that stage. But when we first measured the plate voltage, it was only about 3.5V, as I recall, and we were expecting 80V; that a pretty big drag-down: http://www.nostalgiaair.org/PagesByModel/774/M0013774.pdf
:
:But here is why I think your theory may be correct: when we first measured the low voltage on the plate pin of the tube's socket, we also backed up and measured the B+ on the primary of the 2nd IF xfmr winding. It was way low, too. So it couldn't have been a bad connection at the plate pin's socket. I remember thinking that the problem must be upstream of the IF xfmr winding, but didn't think of voltage drag-down. Your theory may explain our observation.
:
:When Paul touched, the second time, what was supposedly the plate-pin connection with the DMM probe and the radio came to life - maybe we were mistakenly on the grid pin or maybe the force on the plate pin somehow translated to the grid pin.
:
:I didn't write down all the other tubes' plate voltages (they were reasonable), but I think they may have been a tad low, too, particularly in relation to the filament voltages, which were OK. Again, that would seem to be in favor of your theory.
:
:As to your Philco tube socket theory, I just don't remember what the socketw were like. Paul has the set and can check.
:
:Paul, you need to clean all the socket connections for the IF tube and, if necessary, use Edd's suggestion for improving pin tension.
:Doug
:
::
::
::
::
::I wonder what the chances are of that Peel-Co chassis having using the two sheet wafer sockets?
::
::As per:
::
::
::
::The first generation of those used the contacts pin construction of folding the socket pins metal over into a triangle configuration
::
::so that contact was make only by the VERY small area of the two 180 deg opposing rectangular contacts….. pressing into the
::
::individual tube pin that protruded in between them. PLUS there was not a whole lot of tensioning that was provided, with time the pin
::
::could float between the opposing contacts.
::
::Later on, they changed and made a circular forming of the contacts so that they engaged more area of the tube pin , thus giving
::
::more surface contact area.
::
::
::I remember getting those old sockets running in a pinch, until replacement could be done later, by initially pulling the tube and using a std
::
::screwdriver (ooops…look out there ! ) to press opposing contacts together to make them touch, thus giving a one shot
::
::re tensioning of all of the pins and then plugging the tube back in.
::
::
::
::I wonder what the chances were of your I.F. tube having its 1st grid floating in that tube socket, thereby being unbiased and pulling
::your
:: B+ voltage readings on that stage down somewhat, UNTIL you made tube socket connectivity, whereupon the radio blasted
::
::to life again.
::
:
:
::
::
::
::73's de Edd
::
::
::
:

The 1U4 tube has pins 1 and 5 connected together internally. Pin 1 or 5 can be used as the filament minus connection. Look up the 1U4 under TUBES on this site and you will see what I mean.

Radiodoc
**********

::Guys
:
:I've got another question. The bottom left of the schematics shows the filament chain, all being connected to 1 & 7 of the sockets. In the main portion of the schematics, the filamnets connections are shown as 1-5 (for pin 1). Am I correct in assuming that either pin 1 or 5 is where the connection is made, as there is NO connection to pin 1 on the IF tube socket, but there is a connection to pin 5, and damn if I can trace the wire in the cramped chassis. The must be correct assumption, or else the radio wouldn't work at all, right?
:
:
:
::Edd, I like your idea of the IF amp tube's grid getting unbiased and dragging down the B+ on that stage. But when we first measured the plate voltage, it was only about 3.5V, as I recall, and we were expecting 80V; that a pretty big drag-down: http://www.nostalgiaair.org/PagesByModel/774/M0013774.pdf
::
::But here is why I think your theory may be correct: when we first measured the low voltage on the plate pin of the tube's socket, we also backed up and measured the B+ on the primary of the 2nd IF xfmr winding. It was way low, too. So it couldn't have been a bad connection at the plate pin's socket. I remember thinking that the problem must be upstream of the IF xfmr winding, but didn't think of voltage drag-down. Your theory may explain our observation.
::
::When Paul touched, the second time, what was supposedly the plate-pin connection with the DMM probe and the radio came to life - maybe we were mistakenly on the grid pin or maybe the force on the plate pin somehow translated to the grid pin.
::
::I didn't write down all the other tubes' plate voltages (they were reasonable), but I think they may have been a tad low, too, particularly in relation to the filament voltages, which were OK. Again, that would seem to be in favor of your theory.
::
::As to your Philco tube socket theory, I just don't remember what the socketw were like. Paul has the set and can check.
::
::Paul, you need to clean all the socket connections for the IF tube and, if necessary, use Edd's suggestion for improving pin tension.
::Doug
::
:::
:::
:::
:::
:::I wonder what the chances are of that Peel-Co chassis having using the two sheet wafer sockets?
:::
:::As per:
:::
:::
:::
:::The first generation of those used the contacts pin construction of folding the socket pins metal over into a triangle configuration
:::
:::so that contact was make only by the VERY small area of the two 180 deg opposing rectangular contacts….. pressing into the
:::
:::individual tube pin that protruded in between them. PLUS there was not a whole lot of tensioning that was provided, with time the pin
:::
:::could float between the opposing contacts.
:::
:::Later on, they changed and made a circular forming of the contacts so that they engaged more area of the tube pin , thus giving
:::
:::more surface contact area.
:::
:::
:::I remember getting those old sockets running in a pinch, until replacement could be done later, by initially pulling the tube and using a std
:::
:::screwdriver (ooops…look out there ! ) to press opposing contacts together to make them touch, thus giving a one shot
:::
:::re tensioning of all of the pins and then plugging the tube back in.
:::
:::
:::
:::I wonder what the chances were of your I.F. tube having its 1st grid floating in that tube socket, thereby being unbiased and pulling
:::your
::: B+ voltage readings on that stage down somewhat, UNTIL you made tube socket connectivity, whereupon the radio blasted
:::
:::to life again.
:::
::
::
:::
:::
:::
:::73's de Edd
:::
:::
:::
::

:Paul,
:
:The 1U4 tube has pins 1 and 5 connected together internally. Pin 1 or 5 can be used as the filament minus connection. Look up the 1U4 under TUBES on this site and you will see what I mean.
:
:Radiodoc
:**********
:
:
:::Guys
::
::I've got another question. The bottom left of the schematics shows the filament chain, all being connected to 1 & 7 of the sockets. In the main portion of the schematics, the filamnets connections are shown as 1-5 (for pin 1). Am I correct in assuming that either pin 1 or 5 is where the connection is made, as there is NO connection to pin 1 on the IF tube socket, but there is a connection to pin 5, and damn if I can trace the wire in the cramped chassis. The must be correct assumption, or else the radio wouldn't work at all, right?
::
::
::
:::Edd, I like your idea of the IF amp tube's grid getting unbiased and dragging down the B+ on that stage. But when we first measured the plate voltage, it was only about 3.5V, as I recall, and we were expecting 80V; that a pretty big drag-down: http://www.nostalgiaair.org/PagesByModel/774/M0013774.pdf
:::
:::But here is why I think your theory may be correct: when we first measured the low voltage on the plate pin of the tube's socket, we also backed up and measured the B+ on the primary of the 2nd IF xfmr winding. It was way low, too. So it couldn't have been a bad connection at the plate pin's socket. I remember thinking that the problem must be upstream of the IF xfmr winding, but didn't think of voltage drag-down. Your theory may explain our observation.
:::
:::When Paul touched, the second time, what was supposedly the plate-pin connection with the DMM probe and the radio came to life - maybe we were mistakenly on the grid pin or maybe the force on the plate pin somehow translated to the grid pin.
:::
:::I didn't write down all the other tubes' plate voltages (they were reasonable), but I think they may have been a tad low, too, particularly in relation to the filament voltages, which were OK. Again, that would seem to be in favor of your theory.
:::
:::As to your Philco tube socket theory, I just don't remember what the socketw were like. Paul has the set and can check.
:::
:::Paul, you need to clean all the socket connections for the IF tube and, if necessary, use Edd's suggestion for improving pin tension.
:::Doug
:::
::::
::::
::::
::::
::::I wonder what the chances are of that Peel-Co chassis having using the two sheet wafer sockets?
::::
::::As per:
::::
::::
::::
::::The first generation of those used the contacts pin construction of folding the socket pins metal over into a triangle configuration
::::
::::so that contact was make only by the VERY small area of the two 180 deg opposing rectangular contacts….. pressing into the
::::
::::individual tube pin that protruded in between them. PLUS there was not a whole lot of tensioning that was provided, with time the pin
::::
::::could float between the opposing contacts.
::::
::::Later on, they changed and made a circular forming of the contacts so that they engaged more area of the tube pin , thus giving
::::
::::more surface contact area.
::::
::::
::::I remember getting those old sockets running in a pinch, until replacement could be done later, by initially pulling the tube and using a std
::::
::::screwdriver (ooops…look out there ! ) to press opposing contacts together to make them touch, thus giving a one shot
::::
::::re tensioning of all of the pins and then plugging the tube back in.
::::
::::
::::
::::I wonder what the chances were of your I.F. tube having its 1st grid floating in that tube socket, thereby being unbiased and pulling
::::your
:::: B+ voltage readings on that stage down somewhat, UNTIL you made tube socket connectivity, whereupon the radio blasted
::::
::::to life again.
::::
:::
:::
::::
::::
::::
::::73's de Edd
::::
::::
::::
:::

Somehow, Pin 5 must be connected to Pin 1, possibly in the socket? Check for continuity between Pins 1 and 5.
Doug

::Guys
:
:I've got another question. The bottom left of the schematics shows the filament chain, all being connected to 1 & 7 of the sockets. In the main portion of the schematics, the filamnets connections are shown as 1-5 (for pin 1). Am I correct in assuming that either pin 1 or 5 is where the connection is made, as there is NO connection to pin 1 on the IF tube socket, but there is a connection to pin 5, and damn if I can trace the wire in the cramped chassis. The must be correct assumption, or else the radio wouldn't work at all, right?
:

:A 1U5 shows Pin 5 not connected inside the tube: http://www.nostalgiaair.org/tubes/1u5.htm
:
:Somehow, Pin 5 must be connected to Pin 1, possibly in the socket? Check for continuity between Pins 1 and 5.
:Doug
:
:::Guys
::
::I've got another question. The bottom left of the schematics shows the filament chain, all being connected to 1 & 7 of the sockets. In the main portion of the schematics, the filamnets connections are shown as 1-5 (for pin 1). Am I correct in assuming that either pin 1 or 5 is where the connection is made, as there is NO connection to pin 1 on the IF tube socket, but there is a connection to pin 5, and damn if I can trace the wire in the cramped chassis. The must be correct assumption, or else the radio wouldn't work at all, right?
::
:

I've double-checked the sockets on the chassis, but unfortunately I don't believe the 2 wafer type are installed. The sockets on the chassis are completely circular, as far as I can tell...not the "eye" shape exhibited in the photo. They also seem to be much thicker. Still, I think that we are on the right track. Something is up with the pins on the IF socket.

Paul

:
:
:
:
:I wonder what the chances are of that Peel-Co chassis having using the two sheet wafer sockets?
:
:As per:
:
:
:
:The first generation of those used the contacts pin construction of folding the socket pins metal over into a triangle configuration
:
:so that contact was make only by the VERY small area of the two 180 deg opposing rectangular contacts….. pressing into the
:
:individual tube pin that protruded in between them. PLUS there was not a whole lot of tensioning that was provided, with time the pin
:
:could float between the opposing contacts.
:
:Later on, they changed and made a circular forming of the contacts so that they engaged more area of the tube pin , thus giving
:
:more surface contact area.
:
:
:I remember getting those old sockets running in a pinch, until replacement could be done later, by initially pulling the tube and using a std
:
:screwdriver (ooops…look out there ! ) to press opposing contacts together to make them touch, thus giving a one shot
:
:re tensioning of all of the pins and then plugging the tube back in.
:
:
:
:I wonder what the chances were of your I.F. tube having its 1st grid floating in that tube socket, thereby being unbiased and pulling
:your
: B+ voltage readings on that stage down somewhat, UNTIL you made tube socket connectivity, whereupon the radio blasted
:
:to life again.
:
:
:
:
:73's de Edd
:
:
:
:
:
:
:
::Doug,
::Well, upside down I suppose the tube socket is easy prey, but of course I would have wiggled the tubes individually to find the most likely culprit, then gone on from there. Keep a couple wood pencils on the bench, but purchase some of those slide on rubber erasers for the lead end, and don't sharpen it or stick the lead end into the electronics without the eraser in place. Graphite (read resistor) is conductive. Both ends can be used for plucking around and the big eraser is great for locating microphonic tubes.
::
::marv
::
:::Marv, how right you are!
:::
:::Two weak arguments in my defense. The wiring on those post-war portables is very tight, and easy to make a mistake. Secondly, it was Paul who did the wiggling and the shorting. (Unfortuately, it was I who handed him the screwdriver, and told him to use it for wiggling connections.)
:::
:::The next time I encounter a swizzle stick, I will save it.
:::
:::Seriously, do you have any comment on our troubleshooting approach, other than the screwdriver mistake?
:::Doug
:::
:::
::::Hmmmm! This time of year, surprised you didn't use a "swizzle stik" instead of the screwdriver. I keep an ample supply of screwdriver swizzle stiks (plastic)on my bench at all times, but having switched to the red, only use them on special occassions for testing radios.
::::
::::
::::marv
::::
:::::Paul G. and I got together today at my house to go through his completely dead Philco AC/DC portable - wood grill and very nice leather case.
:::::
:::::Two problems initially: one tube was burned out (with all the filaments in series); I had a spare. Secondly, the set originally had a selenium diode, that had been replaced in the past with a silicon diode and a dropping resistor, possibly 100 ohms. The added dropping resistor was in bad physical condition and wide open. We shunted the open dropping resistor. Still no joy, even though the tubes were lighted and the audio section was OK, with a hum.
:::::
:::::Then we checked the B+ at each tube. All were OK, except for the IF amp tube, which was way low. We went back to double-check that tube's B+, and in the process of touching probes to the plate and cathode pins, the radio came alive - sounded good, picking up distant broadcast stations. Must have been a loose connection, right?
:::::
:::::Then we went back to wiggle that tube's socket pins with a small screwdriver (mistake) to see what might be loose. In the process, we shorted either B+ or 120V AC (more likely, I think) to the filament string. Audible and visual spark. All five tubes' filaments were burned out. (Ouch, but they're not all that rare.)
:::::
:::::As luck would have it, Paul had a replacement set of tubes on order from RadioDaze, so soon he will be able to try to get this back in operation.
:::::
:::::He's understandably worried that maybe we damaged something in the radio. Time will tell, but I doubt it.
:::::
:::::Comments?
:::::Doug

(I like Edd's theory a lot, but maybe Edd himself is kind of a strange guy?)
Doug

Will do. I should know something one way or another by tomorrow afternoon. I'll keep you posted. Have you done any reading-up on Constantine yet?

Paul

:Paul, when you get your new set of tubes - and if the set still doesn't work - check the plate voltage (plate to filament) from the bottom of the chassis. If it's way low, then pull the tube, and recheck the same voltage. If it's then up where it should be, then the tube itself must be dragging down the B+, per Edd's theory.
:
:(I like Edd's theory a lot, but maybe Edd himself is kind of a strange guy?)
:Doug

Doug:
Do you know of any radio techs that are not a little bit strange in the eyes of their neighbors??
Lewis
PS Myself included.

By the way, how was your trip to the beer city?

::: Doug

Do you remember the wattage of the 100 ohm resistor array that we used in lieu of the exploded sand type?

Paul

:::Doug
::
::Will do. I should know something one way or another by tomorrow afternoon. I'll keep you posted. Have you done any reading-up on Constantine yet?
::
::Paul
::
:::Paul, when you get your new set of tubes - and if the set still doesn't work - check the plate voltage (plate to filament) from the bottom of the chassis. If it's way low, then pull the tube, and recheck the same voltage. If it's then up where it should be, then the tube itself must be dragging down the B+, per Edd's theory.
:::
:::(I like Edd's theory a lot, but maybe Edd himself is kind of a strange guy?)
:::Doug
:
:Doug:
:Do you know of any radio techs that are not a little bit strange in the eyes of their neighbors??
:Lewis
:PS Myself included.

Never made it to MKE, caught a nonstop to Madison (MSN)
rented a car, and spent Christmas in the land of funny white stuff that falls out of the sky and piles up on the ground. Ate and drank to excess, had a nice Christmas.
Lewis

You can estimate the total DC current through the diode by observing from the schematic that R24 (which is 120 ohms) drops 5 volts. 5/120 = 0.04A. Thus the power disipated by a 100-ohm dropping resistor = 0.04^2 x 100 = 0.16W. Double that for safety - so even a 1/2-W resistor should be fine.
Doug

: Doug
:Do you remember the wattage of the 100 ohm resistor array that we used in lieu of the exploded sand type?
:
:Paul

Paul

:Paul, we had two 1/2-W, 220-ohm resistors in parallel. This is equal to 1-W, 110-ohm.
:
:You can estimate the total DC current through the diode by observing from the schematic that R24 (which is 120 ohms) drops 5 volts. 5/120 = 0.04A. Thus the power disipated by a 100-ohm dropping resistor = 0.04^2 x 100 = 0.16W. Double that for safety - so even a 1/2-W resistor should be fine.
:Doug
:
:: Doug
::Do you remember the wattage of the 100 ohm resistor array that we used in lieu of the exploded sand type?
::
::Paul
:

:::(I like Edd's theory a lot, but maybe Edd himself is kind of a strange guy?)
:::Doug
:
:Doug:
:Do you know of any radio techs that are not a little bit strange in the eyes of their neighbors??
:Lewis
:PS Myself included.

marv

:Paul, when you get your new set of tubes - and if the set still doesn't work - check the plate voltage (plate to filament) from the bottom of the chassis. If it's way low, then pull the tube, and recheck the same voltage. If it's then up where it should be, then the tube itself must be dragging down the B+, per Edd's theory.
:
:(I like Edd's theory a lot, but maybe Edd himself is kind of a strange guy?)
:Doug

Hey, Marv, I think that is a very good idea no matter what Doug thinks of it (;>). Those little 1 Volt filaments go faster than a light bulb when over Volted.
Also, a toothpick wetted with contact cleaner GENTLY inserted into the tube socket pins might remove some corrosion causing the problem.
Lewis
:

:Doug,
:May I respectfully suggest (with your concurrence) that Paul remove all the tubes previously destroyed in probing, make all voltage measurements (empty sockets), wiggle sockets/soldering for any inconsistencies/required repair, insert tubes one at a time and repeat measurements until all tubes are in place successfully.
:
:marv
:

marv

:Marv: Good idea. Of course, with just one tube installed, there won't be any filament voltage to measure, since they are in series. And the plate voltage will be high.
:Doug
:
:
::Doug,
::May I respectfully suggest (with your concurrence) that Paul remove all the tubes previously destroyed in probing, make all voltage measurements (empty sockets), wiggle sockets/soldering for any inconsistencies/required repair, insert tubes one at a time and repeat measurements until all tubes are in place successfully.
::
::marv
::
:

Glad to repeat that the Philco portable is working and sounds absolutely fantastic! So much so that I had to phone Doug for a listen...the tuning is incredibly sensitive, and the volume is unbeatable!!! I never did find any loose connections, further low voltages, or pin problems with the IF socket, however in the process of moving the chassis to resolder the resistor array used to replace the resistor that once replaced the selenium rectifier, a half-inch long single strand of wire fell out. I have a sneaky suspicion that it was bridging something or another inside the chassis and went undetected in Doug's basement...the lighting wasn't all that great in there. Thanks again for all of your help; you guys are out of sight!!! Now onto the next one!!! This is darn fun y'all!!!

Paul

:Paul G. and I got together today at my house to go through his completely dead Philco AC/DC portable - wood grill and very nice leather case.
:
:Two problems initially: one tube was burned out (with all the filaments in series); I had a spare. Secondly, the set originally had a selenium diode, that had been replaced in the past with a silicon diode and a dropping resistor, possibly 100 ohms. The added dropping resistor was in bad physical condition and wide open. We shunted the open dropping resistor. Still no joy, even though the tubes were lighted and the audio section was OK, with a hum.
:
:Then we checked the B+ at each tube. All were OK, except for the IF amp tube, which was way low. We went back to double-check that tube's B+, and in the process of touching probes to the plate and cathode pins, the radio came alive - sounded good, picking up distant broadcast stations. Must have been a loose connection, right?
:
:Then we went back to wiggle that tube's socket pins with a small screwdriver (mistake) to see what might be loose. In the process, we shorted either B+ or 120V AC (more likely, I think) to the filament string. Audible and visual spark. All five tubes' filaments were burned out. (Ouch, but they're not all that rare.)
:
:As luck would have it, Paul had a replacement set of tubes on order from RadioDaze, so soon he will be able to try to get this back in operation.
:
:He's understandably worried that maybe we damaged something in the radio. Time will tell, but I doubt it.
:
:Comments?
:Doug

With work and patience comes just rewards….and it looks like you were aptly rewarded !

Glad to hear that the unit is operational again….. after its one looooong extended hiatus.

Thinking of its vintage being circa 53ish and the state of development of battery powered sets at that time tends to suggest of it being amongst the very last of the battery operated portables, with the onset of the solid state vintage to come within but a few years.(54-55)


That set had just about all of the circuitry refinements that could be in a set, with its full 3 section tuning condenser providing an extra tune stage for the frontal RF tube and its circuitry. The utilization of 265khz in the IF strip so that a bit of extra gain could be acquired, as compared to a set using 455khz units.

And correct me….since I am blind and can’t see the set…..isn’t that one loooong ferrite rod antenna at the top center above chassis, running across almost all of the top insides of the cabinet ? If so….that units Q factor should additionally enhance performance.


BTW…If you are feeling up to it, might not be a bad idea to take B+, screen and plate voltages thru the set and log down and save for future troubleshooting referencing, from a now operational set, in case such info is needed in the future.

Aside: HEYYYY…. here I was away for the weekend and ….did I detect/ interpret a state of Edd bashing going on there ? … OR was it all merely a confirmation that we Electroniques aficionados tend to be attuned in to the beat of a different drum……. in both our actions and logic.

73's de Edd

:::: TO ALL
:
:Glad to repeat that the Philco portable is working and sounds absolutely fantastic! So much so that I had to phone Doug for a listen...the tuning is incredibly sensitive, and the volume is unbeatable!!! I never did find any loose connections, further low voltages, or pin problems with the IF socket, however in the process of moving the chassis to resolder the resistor array used to replace the resistor that once replaced the selenium rectifier, a half-inch long single strand of wire fell out. I have a sneaky suspicion that it was bridging something or another inside the chassis and went undetected in Doug's basement...the lighting wasn't all that great in there. Thanks again for all of your help; you guys are out of sight!!! Now onto the next one!!! This is darn fun y'all!!!
:
:Paul
:
:
::Paul G. and I got together today at my house to go through his completely dead Philco AC/DC portable - wood grill and very nice leather case.
::
::Two problems initially: one tube was burned out (with all the filaments in series); I had a spare. Secondly, the set originally had a selenium diode, that had been replaced in the past with a silicon diode and a dropping resistor, possibly 100 ohms. The added dropping resistor was in bad physical condition and wide open. We shunted the open dropping resistor. Still no joy, even though the tubes were lighted and the audio section was OK, with a hum.
::
::Then we checked the B+ at each tube. All were OK, except for the IF amp tube, which was way low. We went back to double-check that tube's B+, and in the process of touching probes to the plate and cathode pins, the radio came alive - sounded good, picking up distant broadcast stations. Must have been a loose connection, right?
::
::Then we went back to wiggle that tube's socket pins with a small screwdriver (mistake) to see what might be loose. In the process, we shorted either B+ or 120V AC (more likely, I think) to the filament string. Audible and visual spark. All five tubes' filaments were burned out. (Ouch, but they're not all that rare.)
::
::As luck would have it, Paul had a replacement set of tubes on order from RadioDaze, so soon he will be able to try to get this back in operation.
::
::He's understandably worried that maybe we damaged something in the radio. Time will tell, but I doubt it.
::
::Comments?
::Doug

By the way, that ferrite antenna (I assume that's what it is made of) was very large. During the few minutes the set was working in my presence, it was sucking in lots of BC stations. It also has shortwave, so it probably works well on that band, too.

Some of the last tube-type sets from the '50s used printed ckt boards. This one is all point2point wiring. But the chassis is cramped, and I wouldn't like to be the one to recap it. Since it's working well with no hum, I suspect Paul will leave well enough alone.

Edd, please help me - why does the lower IF freq allow higher gain?
Doug

Paul

:Edd bashing? Who, me?
:
:By the way, that ferrite antenna (I assume that's what it is made of) was very large. During the few minutes the set was working in my presence, it was sucking in lots of BC stations. It also has shortwave, so it probably works well on that band, too.
:
:Some of the last tube-type sets from the '50s used printed ckt boards. This one is all point2point wiring. But the chassis is cramped, and I wouldn't like to be the one to recap it. Since it's working well with no hum, I suspect Paul will leave well enough alone.
:
:Edd, please help me - why does the lower IF freq allow higher gain?
:Doug

:Edd bashing? Who, me?
:
:By the way, that ferrite antenna (I assume that's what it is made of) was very large. During the few minutes the set was working in my presence, it was sucking in lots of BC stations. It also has shortwave, so it probably works well on that band, too.
:
:Some of the last tube-type sets from the '50s used printed ckt boards. This one is all point2point wiring. But the chassis is cramped, and I wouldn't like to be the one to recap it. Since it's working well with no hum, I suspect Paul will leave well enough alone.
:
:Edd, please help me - why does the lower IF freq allow higher gain?
:Doug