Philco Power Supply Problem

[dave1138]

I have a Philco 51-T1834 set that appears to have a short somewhere in the B+. Here's what has been done: ALL of the capacitors have been replaced including the micas, the filter caps all have voltage ratings as specified in the Sams (148-13) BOM. All resistors have been checked and any out of tolerance ones replaced with ones having appropriate wattage ratings. The set played quite well after the parts replacement, logging around 20 hours of use. The vertical output transformer failed, and I installed a NOS replacement. After another 4-5 hours of use, I started getting arc-over in the rectifier tubes. I put the set aside to start on other projects about a year ago. I am ready to look at it again and I have a couple of theories to test. One is that the transformer windings may have developed a short, the other that surge voltage exceeding the electrolytics' ratings have caused them to fail. I have another Philco chassis for parts in case the transformer has failed and if the filter caps have failed I want to find caps with a higher voltage rating and add inrush current limiters. My question is, if the caps have failed, where is the best place to add the ICLs? Does limiting surges on the primary side of the power transformer affect the B+ surges or is it better to add them to the B+ line?

[Don Lindsly]

I suggest:

1. Remove the rectifiers and turn on the TV. The other tubes should light up, but nothing more. No smoke or loud hum. Let operate that way for a couple of hours to make sure the transformer is OK to that point.
2. Disconnect and check resistance to ground from rectifier filaments. Should be very high. Disconnect B+ connection from rectifier filaments. Read filaments to ground. Should be very, very high, megs or more.
3. With B+ still disconnected, put rectifiers back and turn on. That will test transformer and rectifiers under no load. There should be no electrolytics connected at this point so the no-load condition will not hurt anything.
4. If it operates in that mode, the transformer is probably fine and the trouble is in the operating circuits. With power off, trace out shorts with an ohm meter.

At this stage, basic troubleshooting will benefit more that guess work. With more information, the forum will be more help.

[47'Plymouth]

I would like to have a F2 sweep chassis for my 1952'Philco console
Cause it's screwed up from a technician from old,that didnt know what he was doing!
So if you got one please let know...just PM me thanks Jody