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philco 40-135 Static problem - Eric - 04-05-2015

Good morning,
 I have a Philco 40-135    http://www.nostalgiaair.org/PagesByModel/328/M0013328.pdf 
That I have recapped, replaced the output transformer replaced the deteriorated wiring checked and replaced out of spec resistors , tubes check good and have even replaced them one a a time to no improvement, looked for bad solder joints and things touching that shouldn't and cleaned and lubed the switch.
   I get a lot of static between the stronger stations, they come in great but the more distant ones have some static. It doesn't seem to matter how long I leave it on I also have a 40-140 that plays great. Should I start looking at the Mica Caps? Not sure where to go at this point. Thanks

Eric

RE: philco 40-135 Static problem - Radioroslyn - 04-05-2015

Do both sets have large loop anttenas? Are both table or floor models???
Terry

RE: philco 40-135 Static problem - Eric - 04-05-2015

(04-05-2015, 11:28 AM)Radioroslyn Wrote:  Do both sets have large loop anttenas? Are both table or floor models???
Terry

Both are table sets and both have loop ant's

RE: philco 40-135 Static problem - Eric - 04-05-2015

Went back over the print and chassis and found 3 resistors 2 of which looked like small caps they were #20, 29,and 30 all were over 40% seems to be much better. I'm going to put it back in the cabinet and give a go.

Thanks Eric

RE: philco 40-135 Static problem - Eric - 04-05-2015

No go, the static seems to come and go to varying degrees, I have looked for bad solder joints and what ever I can think of just when I think I have it and put it in the cabinet it starts again. The static reminds me of what you get on AM when thunder storms are in the area ( there aren't any today here). 

RE: philco 40-135 Static problem - Radioroslyn - 04-05-2015

I think your best bet is to use a signal tracer going from control grid (input of stage) to plate (output of stage). This will help you determine where the noise coming form. If it was 20yrs newer I'd say it's a bad cap in the Ktran IF transformer.
Terry

RE: philco 40-135 Static problem - David - 04-05-2015

Have you cleaned the tube sockets? Take a real close look at the tuner for dirt or dust balls down deep, I like to use a flashlight and a hand lens. Good luck David 

RE: philco 40-135 Static problem - Chuck Schwark - 04-06-2015

..and I would not totally rule out "silver-mica disease" either in the IF cans.

And related to that, although a long shot, might be dirty micas sheets in the tuning gang trimmers too.



Chuck

RE: philco 40-135 Static problem - Eric - 04-06-2015

(04-05-2015, 08:13 PM)David Wrote:  Have you cleaned the tube sockets? Take a real close look at the tuner for dirt or dust balls down deep, I like to use a flashlight and a hand lens. Good luck David 

I have cleaned the tube pins knowing that locktals can have a problem with corrosion but you can usually hear the difference when you wiggle each tube with the set on. On the Tuner I have cleaned and checked the plates and at the shaft making sure there is no trash bridging the segments, As a side note I have one of those magnifier visor, best thing I ever bought leaves your hands free!

May have found the problem it is the trimmer on the tuner will run it for a few days to see it that is what it is.