Phooey, my 53 Philco is on the fritz.

[Eric H]

Fired up the trusty 53 Philco last night to see if a modulator system was working and all I got was this shrunken up raster.

This set has worked perfectly since I rebuilt it about 8 or 10 years ago, it doesn't get used much but I turn it on now and then to keep it healthy.
It was working a month ago, now it seems to have developed a power supply problem as everything is malfunctioning, weak sound, picture and it fades to black when the brightness is turned up.

It looks like the yoke might have moved, possible since one of the cloth straps that hold it in place is broken, that doesn't explain the weak shrunken raster.

I think I left the original Seleniums in place, perhaps one has failed, no bad smells though.

[mbates14]

the original seleniums? yeap id say it failed.

[jr_tech]

But the neck shadow on the right-hand side, the tilt of the raster and the poor focus lend some credibility to the "broken strap" idea, as well.
jr

[jeyurkon]

Originally Posted by Eric H

Fired up the trusty 53 Philco last night to see if a modulator system was working and all I got was this shrunken up raster.

This set has worked perfectly since I rebuilt it about 8 or 10 years ago, it doesn't get used much but I turn it on now and then to keep it healthy.
It was working a month ago, now it seems to have developed a power supply problem as everything is malfunctioning, weak sound, picture and it fades to black when the brightness is turned up.

It looks like the yoke might have moved, possible since one of the cloth straps that hold it in place is broken, that doesn't explain the weak shrunken raster.

I think I left the original Seleniums in place, perhaps one has failed, no bad smells though.

The seleniums might be on the way to smelling bad though. They might be getting hot.

Depending on the quality of the electrolytics you used they might be going already too. Some have disappointed me as soon as I received them.

John

[jeyurkon]

Is that a hum bar or an effect of shutter speed?

John

[Dan Starnes]

Dont you hate when ole trusty fails, I always get a real down feeling when something I have complete faith in has problems. I get real anxious and have to fix it immediately. Probably some OCD on my part.

[Eric H]

I pulled the PS chassis out this evening, not only did I not replace the Seleniums I also didn't replace any of the Electrolytics, they held up well though so no regrets there.
One of the cans was replaced with a Sprague at some point, the date code on it is 1964 so I may leave that one alone, I suspect it's the four section that's causing the problem.

I'll replace the Lytics on this chassis and see if that fixes it, I'll probably leave the Seleniums in if they're OK, dealing with dropping resistors is a pain in neck.

I also need to clean the volume control which is a little flaky and replace the 1/4A Cathode resistor that I jumped with a very fine piece of wire back when I rebuilt it the first time.

[Eric H]

There's a couple small mystery's with this set.

First, it has a Tone control knob behind the Vol Control, the control panel isn't marked for a Tone control though.

Second, the model tag on the back has been blacked out and a new model # stamped on it, this is a factory mod.

The original model is legible under a bright light an was an A-T2288S
the new # is -22 B 4309, the B is written in by hand and is barely visible, maybe it means Blond though the set is more of a Maple.

Could it be they put the wrong chassis in at the factory or maybe just the wrong model tag, or perhaps a revision with a Tone control added and they just redid the tag by hand?

The chassis is a PWR J2.

[jeyurkon]

Originally Posted by Eric H

I pulled the PS chassis out this evening, not only did I not replace the Seleniums I also didn't replace any of the Electrolytics, they held up well though so no regrets there.
One of the cans was replaced with a Sprague at some point, the date code on it is 1964 so I may leave that one alone, I suspect it's the four section

I'll replace the Lytics on this chassis and see if that fixes it, I'll probably leave the Seleniums in if they're OK, dealing with dropping resistors is a pain in neck.

I also need to clean the volume control which is a little flaky and replace the 1/4A Cathode resistor that I jumped with a very fine piece of wire back when I rebuilt it the first time.

I thought I was the only one who keeps the old electrolytics.

[Don Lindsly]

The 120 at 150 input filter is the first suspect. Next is the first two filter sections before and after the choke. The seleniums may be bad, but they are not the primary cause.

Philco may have sone dumb things, but did not make factory mods/mistakes as described. It is more likely a dealer or used TV shop made two TVs from one. Manufacturing was the best functioning department of all.

[Eric H]

It's alive again!

First I tried replacing the 120@150, I had a NOS 1978 dated Twist Lok can that was 300@150, close enough for a filter, but the set still didn't work.

It needed to be changed anyhow because it had been leaking and there was corrosion evident on the bottom, sure to fail soon.

Next I tried jumping the Selenium's, one at a time but it made no real difference, one made the picture slightly larger but not enough to matter.

Well it turned out the problem was the "new" 1964 dated replacement Cap, I jumped it, plugged it in and I knew I had found the problem when I heard the high voltage come on with a strong crackle!
Junk cap, it only lasted 46 years.

I'll probably go ahead and replace all the Electrolytics since one was bad and another was leaking.

I may do the Selenium Rectifiers if the B+ isn't fully up to spec, I don't have a schematic for it though so I don't know what the spec is?

[miniman82]

Pfft, it doesn't even LOOK bad. My brothers old Tek 'scope had a bunch of low voltage FP style caps in it, one of which had swollen so much that some rubber was pushing it's way through the holes in the bottom along with some of the electrolyte. :p


You're lucky though, I picked an old Sparton 21" set out of the trash that had a shorted can not long ago. It was the first one in the power supply chain, so it shorted the rectifier long enough to melt the pins internally and crack the glass. Luckily that and a few black beauties was all that had gone wrong, it works fine now.

[jr_tech]

Originally Posted by Eric H

I may do the Selenium Rectifiers if the B+ isn't fully up to spec, I don't have a schematic for it though so I don't know what the spec is?

My schematic* for 53-T 1853, 2127, 2266, 2268, 2269, 2270, 2271, 2273 code 126 ch J-1,91 shows 245V and -21V, -20V at the power supply output. Both my 17" sets run slightly higher than that.

*Sams set 185, folder 10 (11/52).

jr

[Eric H]

I took the chassis to work today and replaced the bad cap, I don't know exactly what went bad in it, it wasn't dried out at all, in fact it was one of the wettest caps I've torn apart, probably because it's relatively new, probably the connector to the lug went bad is my guess.

I was going to put it back in tonight and try it but I forgot to bring the chassis home.

Maybe I'll go ahead and restuff the last can, if I can find a 475 volt capacitor in my stash, it's only 56 years old so it really shouldn't be bad.

[jeyurkon]

Originally Posted by Eric H

...Maybe I'll go ahead and restuff the last can, if I can find a 475 volt capacitor in my stash, it's only 56 years old so it really shouldn't be bad.

It must have been an infant mortality.