Sync Problem

[vts1134]

Originally Posted by old_coot88

Since you've replaced all the electrolytics (and verified they're all in correct polarity), i would tend to suspect wiring error at this point. Does the schematic show any of the electrolytics "floating" (ie., not connected directly to chassis ground)?
Is this set the RCA 630ts that was having the low B+ issue?

There are a number of good oscilloscope tutorials on Google. But the problem at hand should be easy enuff to resolve without a scope.

I tend to think wiring error also, nobody's prefect least of all me . There are four floating electrolytics and two which are at ground.
This is the 630 with the low B+. I went through section by section and found where it was bogging down and fixed that problem.
I did find some nice tutorials on youtube about scopes. I think I'll keep this set out of the cabinet for a bit after I'm through with her and get some practical experience.

[Geist]

Hi All;
What did you find that was bogging down the power supply ?? You said that you found it, but didn't say what it was..
I would also suggest (If you do not have it already) that you get the Riders/RCA Manual for the 630.. Phil Nelson has a link from his site.. The Riders show where and the path of each of the wires, (Sometimes its hard to follow) but it all seems to be there.. and by following that you can find where each end is connected to.. Check with an ohm meter and mark it on a seperate piece of paper, as done and as wired correctly.. That seperate piece of paper should be a schematic.. Please let us know of your progress and what you did and what you found that was wrong.. It may help the rest of us when we have to go and do the same kind of thing in our sets..
THANK YOU Marty

[old_coot88]

Originally Posted by vts1134

...There are four floating electrolytics and two which are at ground.

Um.. if they are at ground, they wouldn't be floating.

This is the 630 with the low B+. I went through section by section and found where it was bogging down and fixed that problem.

Just curious, what wuzzit?

I did find some nice tutorials on youtube about scopes. I think I'll keep this set out of the cabinet for a bit after I'm through with her and get some practical experience.

Excellent idea. Become reasonably proficient with the scope first, then it can be a useful tool in troubleshooting (such as looking at the waveform of ripple on a B+ line and measuring its amplitude).

[Geist]

Hi All;
Old Coot, I think what He is trying to say, since I have the same set and the same schematics, is that out of the Six Electrolytics, Four are Floating and two are grounded.. Not that two are floating and grounded at the same time..
THANK YOU Marty

[old_coot88]

Aha! Makes perfect sense now.

[vts1134]

This capacitor was the problem. I thought I had gotten all of the caps the first shot around but this one snuck past me.



It was C169 in the schematic below. The picture is rock solid now. Time to move up the chain and improve the picture and sound.

[old_coot88]

Originally Posted by vts1134

This capacitor was the problem. I thought I had gotten all of the caps the first shot around but this one snuck past me.

Well sunnuvugun. Was it shorted? Leaky? Congrads on nailing it.
I'm tryin' to figure the mechanism by which it caused the symptom in your vid.

[vts1134]

Originally Posted by old_coot88

Well sunnuvugun. Was it shorted? Leaky? Congrads on nailing it.
I'm tryin' to figure the mechanism by which it caused the symptom in your vid.

It was not shorted, I don't have a capacitor tester so I don't know if it's leaky. If you figure out how a failure in that part would cause the symptom I had please let me know, I would really like to understand it more.

[vts1134]

Originally Posted by old_coot88

Just curious, what wuzzit?

I think it must have been a tin whisker. I went though the set section by section removing B+ to one area at a time until I found where it bogged down. The problem area was in the lead to the tuner, however when I re-soldered the lead back in the problem disappeared.