Quote:
Originally Posted by bandersen
Didn't say your B+ was OK, just explaining how the power supply works. That cap shouldn't be getting warm.
That is a 7.5 ohm fusible resistor. They were commonly used to protect the selenium rectifiers from a surge on power up as well as act as a fuse for the B+. The value isn;t critial but you may want to increase it a bit if you replaced the seleniums with silicon diodes. Silicon is more efficient and will raise the B+.
While the Sams doesn't state the B+ right at C2, they do list many other voltages. If they are close, I'd say your B+ is OK.
Those are ceramic caps and rarely go bad. Don't mess with them.
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I was just figuring B+ should be around where its supposed to be. With how the set operates. I think I will swap that cap...again. This will be the 3rd time.
After I check some values at the tubes, i'll decide on whether or not to change that resistor's value. I'll probably go up to a 10ohm on it. Would it be good to find another fuseable resistor?
I'll leave them caps alone for now.
Quote:
Originally Posted by mrjukebox160
I read that you had the diodes in backwards at first. If C1 and/or C2A are getting warm I would change out the diodes just in case one was damaged with the high current draw from being backwards. I would start over with fresh caps and diodes. I would also check the field coil on the speaker for any short to ground or low resistance. I don't think the sams had an ohm reading for it maybe the original one does. If it has a partial short to itself it won't filter the B+ correctly and cause "hum bars" in the picture. How is the sound? if you can't get much volume out of it that could be a sign of a bad field coil.
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No big deal to swap diodes, but they did test out good when I switched them the way they should be. hmm, I may have even changed them back then though...don't remember the best since that was about a year and a half ago.
Back when I blew the one cap, I changed out that other one that got warm. Ive also since, swapped some of the caps and simplified things, from how those previous pictures look.
The field coil is fine, no shorts in the speaker. Sound is great as long as the finetuning is set with the picture looking it's worst....
Well, I couldn't find my tube condition chart that I previously made when I started this. I knew I replaced a few tubes in the set, but what one's, I can not remember.
So, I went over all of them again and found some issues. First off, V5(3rd-vid-IF) had the wrong tube.
huh, don't know how I missed that. Could that cause one of my issues, particularly the sound issue? It had a 6AG5WA, when it should have another 6AU6. I also found V4 is shorted out on pins 5 and 7. I've got a bunch of 6AU6's on the way. Seems everything I come across that uses them, those tubes are usually weak.
Also found V9(AF.amp) is weak, so I got a 6J5GT on the way too.
Well, that's where I'm at so far. Haven't done too much with it the last few days. Been working on a number of other things.