I did notice that the electrolytic cap cans were soldered to the chassis although none of the individual electro caps are directly grounded (at least according to the schematic). The black wire out of each of the caps appears to connect to the filament string. Is there supposed to be a ground connection between the electrolytic caps and the chassis?
Thanks//Jeff
The B- line, where negative of electrolytics connect, should be isolated from chassis. Previous owner may have connected them together? This makes the chassis directly connected to one side of the AC line.
Follow the schematic:
http://www.nostalgiaair.org/PagesByModel/306/M0025306.pdf
Cap C2 connects between chassis and B-.
Norm
:I am working on a "bomber" T/O. When I got it, all the previous owner said was that it had a hum and didn't pick up any stations. I recapped the unit, and I can pick up stations but they are really distorted and there is a heavy hum in the speaker. I rechecked the caps, looked over the rubber covered wires for breaks, rechecked the tubes and I can find nothing out of whack.
:
:I did notice that the electrolytic cap cans were soldered to the chassis although none of the individual electro caps are directly grounded (at least according to the schematic). The black wire out of each of the caps appears to connect to the filament string. Is there supposed to be a ground connection between the electrolytic caps and the chassis?
:
:Thanks//Jeff
:
The solder connection on C2 on the ground side was a bit suspect. I also bathed the gang condenser in Deoxit which improved things dramatically. I'm going to spray it again tomorrow and then check the plates. At a certain point towards 700 on the dial it starts to make a scratching noise.
Jeff
:Jeff
:
: The B- line, where negative of electrolytics connect, should be isolated from chassis. Previous owner may have connected them together? This makes the chassis directly connected to one side of the AC line.
:
: Follow the schematic:
:
:http://www.nostalgiaair.org/PagesByModel/306/M0025306.pdf
:
: Cap C2 connects between chassis and B-.
:
:Norm
:
:
:
::I am working on a "bomber" T/O. When I got it, all the previous owner said was that it had a hum and didn't pick up any stations. I recapped the unit, and I can pick up stations but they are really distorted and there is a heavy hum in the speaker. I rechecked the caps, looked over the rubber covered wires for breaks, rechecked the tubes and I can find nothing out of whack.
::
::I did notice that the electrolytic cap cans were soldered to the chassis although none of the individual electro caps are directly grounded (at least according to the schematic). The black wire out of each of the caps appears to connect to the filament string. Is there supposed to be a ground connection between the electrolytic caps and the chassis?
::
::Thanks//Jeff
::
:
:
Any time the chassis is hot, I reverse the plug and there is either a lot less electricity flowing thru it, or none at all.
The chassis going hot on an intermittent basis has me stumped. Has anyone out there had a similar situation with this model T/O?
Thanks///Jeff
:Thanks Norm,
:
:The solder connection on C2 on the ground side was a bit suspect. I also bathed the gang condenser in Deoxit which improved things dramatically. I'm going to spray it again tomorrow and then check the plates. At a certain point towards 700 on the dial it starts to make a scratching noise.
:
:Jeff
:
::Jeff
::
:: The B- line, where negative of electrolytics connect, should be isolated from chassis. Previous owner may have connected them together? This makes the chassis directly connected to one side of the AC line.
::
:: Follow the schematic:
::
::http://www.nostalgiaair.org/PagesByModel/306/M0025306.pdf
::
:: Cap C2 connects between chassis and B-.
::
::Norm
::
::
::
:::I am working on a "bomber" T/O. When I got it, all the previous owner said was that it had a hum and didn't pick up any stations. I recapped the unit, and I can pick up stations but they are really distorted and there is a heavy hum in the speaker. I rechecked the caps, looked over the rubber covered wires for breaks, rechecked the tubes and I can find nothing out of whack.
:::
:::I did notice that the electrolytic cap cans were soldered to the chassis although none of the individual electro caps are directly grounded (at least according to the schematic). The black wire out of each of the caps appears to connect to the filament string. Is there supposed to be a ground connection between the electrolytic caps and the chassis?
:::
:::Thanks//Jeff
:::
::
::
:
:
This is an AC/DC Battery radio. It doesn't have isolation from the AC line. Chassis will be hot depending on polarity of the AC line cord.
Once your radio is in a cabinet shouldn't be a problem as chassis will be insulated from outside.
Norm
:After I finished doing some additional work on the set, I found that the chassis was hot (electrically), but not all the time. I changed out two of the C2 caps, and it actually worked surprisingly well for awhile (no shocks from the chassis - at least for awhile). When I leave it alone for several days and then turn it on, the chassis goes hot again. When I turned it on today, it was not hot at all (it had been on last night).
:
:Any time the chassis is hot, I reverse the plug and there is either a lot less electricity flowing thru it, or none at all.
:
:The chassis going hot on an intermittent basis has me stumped. Has anyone out there had a similar situation with this model T/O?
:
:Thanks///Jeff
:
:
:
::Thanks Norm,
::
::The solder connection on C2 on the ground side was a bit suspect. I also bathed the gang condenser in Deoxit which improved things dramatically. I'm going to spray it again tomorrow and then check the plates. At a certain point towards 700 on the dial it starts to make a scratching noise.
::
::Jeff
::
:::Jeff
:::
::: The B- line, where negative of electrolytics connect, should be isolated from chassis. Previous owner may have connected them together? This makes the chassis directly connected to one side of the AC line.
:::
::: Follow the schematic:
:::
:::http://www.nostalgiaair.org/PagesByModel/306/M0025306.pdf
:::
::: Cap C2 connects between chassis and B-.
:::
:::Norm
:::
:::
:::
::::I am working on a "bomber" T/O. When I got it, all the previous owner said was that it had a hum and didn't pick up any stations. I recapped the unit, and I can pick up stations but they are really distorted and there is a heavy hum in the speaker. I rechecked the caps, looked over the rubber covered wires for breaks, rechecked the tubes and I can find nothing out of whack.
::::
::::I did notice that the electrolytic cap cans were soldered to the chassis although none of the individual electro caps are directly grounded (at least according to the schematic). The black wire out of each of the caps appears to connect to the filament string. Is there supposed to be a ground connection between the electrolytic caps and the chassis?
::::
::::Thanks//Jeff
::::
:::
:::
::
::
:
:
Thanks///Jeff
:Jeff
:
: This is an AC/DC Battery radio. It doesn't have isolation from the AC line. Chassis will be hot depending on polarity of the AC line cord.
:
: Once your radio is in a cabinet shouldn't be a problem as chassis will be insulated from outside.
:
:Norm
:
::After I finished doing some additional work on the set, I found that the chassis was hot (electrically), but not all the time. I changed out two of the C2 caps, and it actually worked surprisingly well for awhile (no shocks from the chassis - at least for awhile). When I leave it alone for several days and then turn it on, the chassis goes hot again. When I turned it on today, it was not hot at all (it had been on last night).
::
::Any time the chassis is hot, I reverse the plug and there is either a lot less electricity flowing thru it, or none at all.
::
::The chassis going hot on an intermittent basis has me stumped. Has anyone out there had a similar situation with this model T/O?
::
::Thanks///Jeff
::
::
::
:::Thanks Norm,
:::
:::The solder connection on C2 on the ground side was a bit suspect. I also bathed the gang condenser in Deoxit which improved things dramatically. I'm going to spray it again tomorrow and then check the plates. At a certain point towards 700 on the dial it starts to make a scratching noise.
:::
:::Jeff
:::
::::Jeff
::::
:::: The B- line, where negative of electrolytics connect, should be isolated from chassis. Previous owner may have connected them together? This makes the chassis directly connected to one side of the AC line.
::::
:::: Follow the schematic:
::::
::::http://www.nostalgiaair.org/PagesByModel/306/M0025306.pdf
::::
:::: Cap C2 connects between chassis and B-.
::::
::::Norm
::::
::::
::::
:::::I am working on a "bomber" T/O. When I got it, all the previous owner said was that it had a hum and didn't pick up any stations. I recapped the unit, and I can pick up stations but they are really distorted and there is a heavy hum in the speaker. I rechecked the caps, looked over the rubber covered wires for breaks, rechecked the tubes and I can find nothing out of whack.
:::::
:::::I did notice that the electrolytic cap cans were soldered to the chassis although none of the individual electro caps are directly grounded (at least according to the schematic). The black wire out of each of the caps appears to connect to the filament string. Is there supposed to be a ground connection between the electrolytic caps and the chassis?
:::::
:::::Thanks//Jeff
:::::
::::
::::
:::
:::
::
::
:
:
Could your hand be wet when getting a shock? Are you touching something grounded at the time? Do you unplug it and reverse plug when reconnecting the radio?
This type radio has a cap from chassis to one side of the AC line. It passes AC but is limited in current by value of the cap. The chassis will be hot depending on plug polarity. This will cause a shock if you are grounded.
You could eliminate the shock by adding an isolation transformer.
Norm
I get a nasty shock from the metal plate behind the tuning and off/on/volume knobs, and from the exterior chassis screw on the left side. But not all of the time. It's working well right this minute. I have to believe something is grounding intermittently to the chassis. Time to look somemore...
:
:Thanks///Jeff
:
::Jeff
::
:: This is an AC/DC Battery radio. It doesn't have isolation from the AC line. Chassis will be hot depending on polarity of the AC line cord.
::
:: Once your radio is in a cabinet shouldn't be a problem as chassis will be insulated from outside.
::
::Norm
::
:::After I finished doing some additional work on the set, I found that the chassis was hot (electrically), but not all the time. I changed out two of the C2 caps, and it actually worked surprisingly well for awhile (no shocks from the chassis - at least for awhile). When I leave it alone for several days and then turn it on, the chassis goes hot again. When I turned it on today, it was not hot at all (it had been on last night).
:::
:::Any time the chassis is hot, I reverse the plug and there is either a lot less electricity flowing thru it, or none at all.
:::
:::The chassis going hot on an intermittent basis has me stumped. Has anyone out there had a similar situation with this model T/O?
:::
:::Thanks///Jeff
:::
:::
:::
::::Thanks Norm,
::::
::::The solder connection on C2 on the ground side was a bit suspect. I also bathed the gang condenser in Deoxit which improved things dramatically. I'm going to spray it again tomorrow and then check the plates. At a certain point towards 700 on the dial it starts to make a scratching noise.
::::
::::Jeff
::::
:::::Jeff
:::::
::::: The B- line, where negative of electrolytics connect, should be isolated from chassis. Previous owner may have connected them together? This makes the chassis directly connected to one side of the AC line.
:::::
::::: Follow the schematic:
:::::
:::::http://www.nostalgiaair.org/PagesByModel/306/M0025306.pdf
:::::
::::: Cap C2 connects between chassis and B-.
:::::
:::::Norm
:::::
:::::
:::::
::::::I am working on a "bomber" T/O. When I got it, all the previous owner said was that it had a hum and didn't pick up any stations. I recapped the unit, and I can pick up stations but they are really distorted and there is a heavy hum in the speaker. I rechecked the caps, looked over the rubber covered wires for breaks, rechecked the tubes and I can find nothing out of whack.
::::::
::::::I did notice that the electrolytic cap cans were soldered to the chassis although none of the individual electro caps are directly grounded (at least according to the schematic). The black wire out of each of the caps appears to connect to the filament string. Is there supposed to be a ground connection between the electrolytic caps and the chassis?
::::::
::::::Thanks//Jeff
::::::
:::::
:::::
::::
::::
:::
:::
::
::
:
: