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stumped on no SW reception Philco 37-38
11/9/2007 9:49:37 PMBrian
I think its time to put it back together and on the shelf. With broadcast working good, I still can't get SW. I can inject a SW signal with a sig gen all along the band, but no stations at all. Adjusted for maximum output as per the instructions.
11/10/2007 12:02:31 AMRCWade
Right now the sun spots are at a minimum, most short wave bands are doing poorly, 75-80 meter ham band is doing well around 9PM local
RCW

:I think its time to put it back together and on the shelf. With broadcast working good, I still can't get SW. I can inject a SW signal with a sig gen all along the band, but no stations at all. Adjusted for maximum output as per the instructions.

11/10/2007 12:23:57 AMNorm Leal
Hi

Short wave does require an antenna while broadcast band may not.

The radio uses a 1C7 for oscillator. If filament is much less than 2 volts the tube may not operate on short wave.

Norm

:Right now the sun spots are at a minimum, most short wave bands are doing poorly, 75-80 meter ham band is doing well around 9PM local
:RCW
:
::I think its time to put it back together and on the shelf. With broadcast working good, I still can't get SW. I can inject a SW signal with a sig gen all along the band, but no stations at all. Adjusted for maximum output as per the instructions.

11/10/2007 10:27:35 AMBrian
Norm,

with this vintage radio would I be looking at a fair length of wire? I'm presently set up in my basement.

Brian

:Hi
:
: Short wave does require an antenna while broadcast band may not.
:
: The radio uses a 1C7 for oscillator. If filament is much less than 2 volts the tube may not operate on short wave.
:
: Norm
:
::Right now the sun spots are at a minimum, most short wave bands are doing poorly, 75-80 meter ham band is doing well around 9PM local
::RCW
::
:::I think its time to put it back together and on the shelf. With broadcast working good, I still can't get SW. I can inject a SW signal with a sig gen all along the band, but no stations at all. Adjusted for maximum output as per the instructions.

11/11/2007 12:07:23 PMNorm Leal
Brian

Usually 10 - 20 feet of wire is enough to pick up something. The best antenna is as high and long as possible. Try the wire attached to the ceiling especially since you are in a basement.

Norm

:Norm,
:
:with this vintage radio would I be looking at a fair length of wire? I'm presently set up in my basement.
:
:Brian
:
::Hi
::
:: Short wave does require an antenna while broadcast band may not.
::
:: The radio uses a 1C7 for oscillator. If filament is much less than 2 volts the tube may not operate on short wave.
::
:: Norm
::
:::Right now the sun spots are at a minimum, most short wave bands are doing poorly, 75-80 meter ham band is doing well around 9PM local
:::RCW
:::
::::I think its time to put it back together and on the shelf. With broadcast working good, I still can't get SW. I can inject a SW signal with a sig gen all along the band, but no stations at all. Adjusted for maximum output as per the instructions.

11/11/2007 10:55:47 PMBrian
I found a possible problem, no readable negative voltage on pin 4 of 1C7, which is the osc. grid. Would this indicate an open oscillator?


:Brian
:
: Usually 10 - 20 feet of wire is enough to pick up something. The best antenna is as high and long as possible. Try the wire attached to the ceiling especially since you are in a basement.
:
:Norm
:
::Norm,
::
::with this vintage radio would I be looking at a fair length of wire? I'm presently set up in my basement.
::
::Brian
::
:::Hi
:::
::: Short wave does require an antenna while broadcast band may not.
:::
::: The radio uses a 1C7 for oscillator. If filament is much less than 2 volts the tube may not operate on short wave.
:::
::: Norm
:::
::::Right now the sun spots are at a minimum, most short wave bands are doing poorly, 75-80 meter ham band is doing well around 9PM local
::::RCW
::::
:::::I think its time to put it back together and on the shelf. With broadcast working good, I still can't get SW. I can inject a SW signal with a sig gen all along the band, but no stations at all. Adjusted for maximum output as per the instructions.

11/12/2007 9:11:12 AMNorm Leal
Brian

No negative voltage on the the oscillator grid shows the tube isn't operating on short wave. Compare with broadcast band voltage reading to be sure.

Not likely the oscillator coil but you should check band switch contacts and coil anyway. Short wave coils use fewer turns, usually heavier wire and don't often open.

A 1C7 tube is not very good oscillating at higher frequencies. Increasing filament voltage or another tube may help? The tube can test good and still not oscillate on short wave frequencies.

Norm

:I found a possible problem, no readable negative voltage on pin 4 of 1C7, which is the osc. grid. Would this indicate an open oscillator?
:
:
::Brian
::
:: Usually 10 - 20 feet of wire is enough to pick up something. The best antenna is as high and long as possible. Try the wire attached to the ceiling especially since you are in a basement.
::
::Norm
::
:::Norm,
:::
:::with this vintage radio would I be looking at a fair length of wire? I'm presently set up in my basement.
:::
:::Brian
:::
::::Hi
::::
:::: Short wave does require an antenna while broadcast band may not.
::::
:::: The radio uses a 1C7 for oscillator. If filament is much less than 2 volts the tube may not operate on short wave.
::::
:::: Norm
::::
:::::Right now the sun spots are at a minimum, most short wave bands are doing poorly, 75-80 meter ham band is doing well around 9PM local
:::::RCW
:::::
::::::I think its time to put it back together and on the shelf. With broadcast working good, I still can't get SW. I can inject a SW signal with a sig gen all along the band, but no stations at all. Adjusted for maximum output as per the instructions.
:
:

11/12/2007 1:14:20 PMBrian
Upon closer examination I found that there is indeed a negative 2 or 3 volts on shortwave but none on the broadcast. I may may dislodged a wire on the coil. Are there continuity tests I can check?

:Brian
:
: No negative voltage on the the oscillator grid shows the tube isn't operating on short wave. Compare with broadcast band voltage reading to be sure.
:
: Not likely the oscillator coil but you should check band switch contacts and coil anyway. Short wave coils use fewer turns, usually heavier wire and don't often open.
:
: A 1C7 tube is not very good oscillating at higher frequencies. Increasing filament voltage or another tube may help? The tube can test good and still not oscillate on short wave frequencies.
:
:Norm
:
::I found a possible problem, no readable negative voltage on pin 4 of 1C7, which is the osc. grid. Would this indicate an open oscillator?
::
::
:::Brian
:::
::: Usually 10 - 20 feet of wire is enough to pick up something. The best antenna is as high and long as possible. Try the wire attached to the ceiling especially since you are in a basement.
:::
:::Norm
:::
::::Norm,
::::
::::with this vintage radio would I be looking at a fair length of wire? I'm presently set up in my basement.
::::
::::Brian
::::
:::::Hi
:::::
::::: Short wave does require an antenna while broadcast band may not.
:::::
::::: The radio uses a 1C7 for oscillator. If filament is much less than 2 volts the tube may not operate on short wave.
:::::
::::: Norm
:::::
::::::Right now the sun spots are at a minimum, most short wave bands are doing poorly, 75-80 meter ham band is doing well around 9PM local
::::::RCW
::::::
:::::::I think its time to put it back together and on the shelf. With broadcast working good, I still can't get SW. I can inject a SW signal with a sig gen all along the band, but no stations at all. Adjusted for maximum output as per the instructions.
::
::

11/12/2007 9:21:13 PMNorm Leal
Brian

You can check continuity of coils marked 11 & 13 in the schematic. Use your ohm meter. I expect one will be open? On some Philco coils you will find a green spot, corrosion.

http://www.nostalgiaair.org/PagesByModel/204/M0013204.pdf

Norm

:Upon closer examination I found that there is indeed a negative 2 or 3 volts on shortwave but none on the broadcast. I may may dislodged a wire on the coil. Are there continuity tests I can check?
:
:
:
::Brian
::
:: No negative voltage on the the oscillator grid shows the tube isn't operating on short wave. Compare with broadcast band voltage reading to be sure.
::
:: Not likely the oscillator coil but you should check band switch contacts and coil anyway. Short wave coils use fewer turns, usually heavier wire and don't often open.
::
:: A 1C7 tube is not very good oscillating at higher frequencies. Increasing filament voltage or another tube may help? The tube can test good and still not oscillate on short wave frequencies.
::
::Norm
::
:::I found a possible problem, no readable negative voltage on pin 4 of 1C7, which is the osc. grid. Would this indicate an open oscillator?
:::
:::
::::Brian
::::
:::: Usually 10 - 20 feet of wire is enough to pick up something. The best antenna is as high and long as possible. Try the wire attached to the ceiling especially since you are in a basement.
::::
::::Norm
::::
:::::Norm,
:::::
:::::with this vintage radio would I be looking at a fair length of wire? I'm presently set up in my basement.
:::::
:::::Brian
:::::
::::::Hi
::::::
:::::: Short wave does require an antenna while broadcast band may not.
::::::
:::::: The radio uses a 1C7 for oscillator. If filament is much less than 2 volts the tube may not operate on short wave.
::::::
:::::: Norm
::::::
:::::::Right now the sun spots are at a minimum, most short wave bands are doing poorly, 75-80 meter ham band is doing well around 9PM local
:::::::RCW
:::::::
::::::::I think its time to put it back together and on the shelf. With broadcast working good, I still can't get SW. I can inject a SW signal with a sig gen all along the band, but no stations at all. Adjusted for maximum output as per the instructions.
:::
:::

12/29/2007 11:30:11 PMBrian
I seem to be inching closer to having SW reception on this radio. By holding my finger on the grid cap or touching tuning gang to the 1C7, and with volume all the way up, I can faintly receive a SW station. I'm still looking at a front end issue? (Audio section seems fine and loud with a sig gen.)
:Brian
:
: You can check continuity of coils marked 11 & 13 in the schematic. Use your ohm meter. I expect one will be open? On some Philco coils you will find a green spot, corrosion.
:
:http://www.nostalgiaair.org/PagesByModel/204/M0013204.pdf
:
:Norm
:
:
:
::Upon closer examination I found that there is indeed a negative 2 or 3 volts on shortwave but none on the broadcast. I may may dislodged a wire on the coil. Are there continuity tests I can check?
::
::
::
:::Brian
:::
::: No negative voltage on the the oscillator grid shows the tube isn't operating on short wave. Compare with broadcast band voltage reading to be sure.
:::
::: Not likely the oscillator coil but you should check band switch contacts and coil anyway. Short wave coils use fewer turns, usually heavier wire and don't often open.
:::
::: A 1C7 tube is not very good oscillating at higher frequencies. Increasing filament voltage or another tube may help? The tube can test good and still not oscillate on short wave frequencies.
:::
:::Norm
:::
::::I found a possible problem, no readable negative voltage on pin 4 of 1C7, which is the osc. grid. Would this indicate an open oscillator?
::::
::::
:::::Brian
:::::
::::: Usually 10 - 20 feet of wire is enough to pick up something. The best antenna is as high and long as possible. Try the wire attached to the ceiling especially since you are in a basement.
:::::
:::::Norm
:::::
::::::Norm,
::::::
::::::with this vintage radio would I be looking at a fair length of wire? I'm presently set up in my basement.
::::::
::::::Brian
::::::
:::::::Hi
:::::::
::::::: Short wave does require an antenna while broadcast band may not.
:::::::
::::::: The radio uses a 1C7 for oscillator. If filament is much less than 2 volts the tube may not operate on short wave.
:::::::
::::::: Norm
:::::::
::::::::Right now the sun spots are at a minimum, most short wave bands are doing poorly, 75-80 meter ham band is doing well around 9PM local
::::::::RCW
::::::::
:::::::::I think its time to put it back together and on the shelf. With broadcast working good, I still can't get SW. I can inject a SW signal with a sig gen all along the band, but no stations at all. Adjusted for maximum output as per the instructions.
::::
::::
12/29/2007 11:41:11 PMThomas Dermody
Did you check the coils as Norm said? Usually they are of thicker wire, but the highest short wave band in my Crosley 1117 was out, and was due to a rather thin broken wire in the oscillator coil. I repaired it and now the short wave works well.

You should be able to pick up short wave signals with a fairly short wire. A long wire will greatly improve reception, but reasonable reception of a few strong signals should be possible with a short wire. They should be of good volume, too.

...Seems to be a problem with Philcos and corrosion, though otherwise Philco radios are quite nice. It might be a good measure for all of us to dip our coils in hot parafin, if we have the time to remove them. Another method might be to drip parafin onto the coils. Perhaps place 'drop cloths' of paper under the coils (where coils aren't placed in cans) to allow the dripping of wax.

T.

12/29/2007 11:46:06 PMfrank
:I seem to be inching closer to having SW reception on this radio. By holding my finger on the grid cap or touching tuning gang to the 1C7, and with volume all the way up, I can faintly receive a SW station. I'm still looking at a front end issue? (Audio section seems fine and loud with a sig gen.)
::Brian
::
:: You can check continuity of coils marked 11 & 13 in the schematic. Use your ohm meter. I expect one will be open? On some Philco coils you will find a green spot, corrosion.
::
::http://www.nostalgiaair.org/PagesByModel/204/M0013204.pdf
::
::Norm
::
::
::
:::Upon closer examination I found that there is indeed a negative 2 or 3 volts on shortwave but none on the broadcast. I may may dislodged a wire on the coil. Are there continuity tests I can check?
:::
:::
:::
::::Brian
::::
:::: No negative voltage on the the oscillator grid shows the tube isn't operating on short wave. Compare with broadcast band voltage reading to be sure.
::::
:::: Not likely the oscillator coil but you should check band switch contacts and coil anyway. Short wave coils use fewer turns, usually heavier wire and don't often open.
::::
:::: A 1C7 tube is not very good oscillating at higher frequencies. Increasing filament voltage or another tube may help? The tube can test good and still not oscillate on short wave frequencies.
::::
::::Norm
::::
:::::I found a possible problem, no readable negative voltage on pin 4 of 1C7, which is the osc. grid. Would this indicate an open oscillator?
:::::
:::::
::::::Brian
::::::
:::::: Usually 10 - 20 feet of wire is enough to pick up something. The best antenna is as high and long as possible. Try the wire attached to the ceiling especially since you are in a basement.
::::::
::::::Norm
::::::
:::::::Norm,
:::::::
:::::::with this vintage radio would I be looking at a fair length of wire? I'm presently set up in my basement.
:::::::
:::::::Brian
:::::::
::::::::Hi
::::::::
:::::::: Short wave does require an antenna while broadcast band may not.
::::::::
:::::::: The radio uses a 1C7 for oscillator. If filament is much less than 2 volts the tube may not operate on short wave.
::::::::
:::::::: Norm
::::::::
:::::::::Right now the sun spots are at a minimum, most short wave bands are doing poorly, 75-80 meter ham band is doing well around 9PM local
:::::::::RCW
:::::::::
::::::::::I think its time to put it back together and on the shelf. With broadcast working good, I still can't get SW. I can inject a SW signal with a sig gen all along the band, but no stations at all. Adjusted for maximum output as per the instructions.
:::::i'm getting awsome shortwave reception here on the coast with a trucker style mobile c.b. antenna grouded to a fire escape rail thru rg58 cable. maybe your unit isn't grounded enough? how about your lead from ant. terminal to circuit? frank
:::::


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