Hello All,
I replaced the monster sized diode someone replaced the original selenium diode with, and replaced that with a 1N400x and a 100 ohm resistor in series with that. When I turn it on, there is a waft of smoke, but I cannot see where that's coming from because I shut off the set as soon as I see the smoke. The smoke stops almost instantly when the power is off. There is obviously no B+ due to a really heavy load somewhere. The filament string works fine though.
If anyone has suggestions what to look at, please let me know. Otherwise, I'll search until I find it. Someone "restored" this set before I received it. So there could be some wiring mistakes as well.

Thanks,

Dave

Hi Dave

Something shorted on the B+ line. Use a variac and set voltage lower so don't get smoke. Doesn't matter if tubes light for testing. Do you have any B+ voltage?

Most likely a cap on the B+ line is shorted.

Norm

:Hello All,
: I replaced the monster sized diode someone replaced the original selenium diode with, and replaced that with a 1N400x and a 100 ohm resistor in series with that. When I turn it on, there is a waft of smoke, but I cannot see where that's coming from because I shut off the set as soon as I see the smoke. The smoke stops almost instantly when the power is off. There is obviously no B+ due to a really heavy load somewhere. The filament string works fine though.
: If anyone has suggestions what to look at, please let me know. Otherwise, I'll search until I find it. Someone "restored" this set before I received it. So there could be some wiring mistakes as well.
:
:Thanks,
:
:Dave
:

Hello Norm,
I probably have B+ but it's loaded way down. The dropping resistor gets quite warm, but I don't think that's what's smoking. I replaced some of the capacitors but someone else, who worked on this set before, replaced the remainder of them. There are a couple of electrolytics that look like they're 70s or 80s vintage. The rest look newer. There's not very much current in this circuit to begin with so any little thing can load it down so far that there is no B+ to measure. I'll keep looking for trouble.
If I disconnect the filter choke, I will probably have full B++.
The problem is on the other side somewhere.

Thanks,

Dave

:Hi Dave
:
: Something shorted on the B+ line. Use a variac and set voltage lower so don't get smoke. Doesn't matter if tubes light for testing. Do you have any B+ voltage?
:
: Most likely a cap on the B+ line is shorted.
:
:Norm
:
::Hello All,
:: I replaced the monster sized diode someone replaced the original selenium diode with, and replaced that with a 1N400x and a 100 ohm resistor in series with that. When I turn it on, there is a waft of smoke, but I cannot see where that's coming from because I shut off the set as soon as I see the smoke. The smoke stops almost instantly when the power is off. There is obviously no B+ due to a really heavy load somewhere. The filament string works fine though.
:: If anyone has suggestions what to look at, please let me know. Otherwise, I'll search until I find it. Someone "restored" this set before I received it. So there could be some wiring mistakes as well.
::
::Thanks,
::
::Dave
::
:

Hello Again Norm,
It turns out it was the usual bent resistor lead touching where it shouldn't problem. I have corrected the mistake and started a new thread for insufficient vertical deflection.

Thanks,

Dave
:Hi Dave
:
: Something shorted on the B+ line. Use a variac and set voltage lower so don't get smoke. Doesn't matter if tubes light for testing. Do you have any B+ voltage?
:
: Most likely a cap on the B+ line is shorted.
:
:Norm
:
::Hello All,
:: I replaced the monster sized diode someone replaced the original selenium diode with, and replaced that with a 1N400x and a 100 ohm resistor in series with that. When I turn it on, there is a waft of smoke, but I cannot see where that's coming from because I shut off the set as soon as I see the smoke. The smoke stops almost instantly when the power is off. There is obviously no B+ due to a really heavy load somewhere. The filament string works fine though.
:: If anyone has suggestions what to look at, please let me know. Otherwise, I'll search until I find it. Someone "restored" this set before I received it. So there could be some wiring mistakes as well.
::
::Thanks,
::
::Dave
::
:

If you have access to a variac and an infared thermometer, you could locate the overheating component very easily.
:Hello All,
: I replaced the monster sized diode someone replaced the original selenium diode with, and replaced that with a 1N400x and a 100 ohm resistor in series with that. When I turn it on, there is a waft of smoke, but I cannot see where that's coming from because I shut off the set as soon as I see the smoke. The smoke stops almost instantly when the power is off. There is obviously no B+ due to a really heavy load somewhere. The filament string works fine though.
: If anyone has suggestions what to look at, please let me know. Otherwise, I'll search until I find it. Someone "restored" this set before I received it. So there could be some wiring mistakes as well.
:
:Thanks,
:
:Dave
:

With the negative lead of your ohm meter connected to the B- line, test for a short from that resistor on through the B+ path. The point of the least resistance is where the short, or leak is.

Hello Again All,
I have found the problem resistor lead touching one of the leads from a HV capacitor. I have removed the problem and I now have a raster. But I don't have quite enough vertical deflection. This will be a new thread.

Thanks,

Dave
:Hello All,
: I replaced the monster sized diode someone replaced the original selenium diode with, and replaced that with a 1N400x and a 100 ohm resistor in series with that. When I turn it on, there is a waft of smoke, but I cannot see where that's coming from because I shut off the set as soon as I see the smoke. The smoke stops almost instantly when the power is off. There is obviously no B+ due to a really heavy load somewhere. The filament string works fine though.
: If anyone has suggestions what to look at, please let me know. Otherwise, I'll search until I find it. Someone "restored" this set before I received it. So there could be some wiring mistakes as well.
:
:Thanks,
:
:Dave
: