Motorola TS-4J - Videokarma.org TV - Video

Zsuttle · #1 07-11-2018, 06:41 PM

We can only guess. The spare had numerous evident repairs. It blew both the diodes when I installed it in the main chassis, but hopefully all of the caps are still within tolerance.

timmy · #2 07-12-2018, 06:37 AM

Quote:

Originally Posted by Zsuttle

We can only guess. The spare had numerous evident repairs. It blew both the diodes when I installed it in the main chassis, but hopefully all of the caps are still within tolerance.

If the caps you mention you hope are still good, then if they are original they won't be.

Electronic M · #3 07-12-2018, 11:21 AM

Quote:

Originally Posted by timmy

If the caps you mention you hope are still good, then if they are original they won't be.

Even if those caps are new if the wiring errors put reverse polarity or AC across any of those caps the ones that got it are done for.

kvflyer · #4 07-12-2018, 05:26 PM

Quote:

Originally Posted by Electronic M

Even if those caps are new if the wiring errors put reverse polarity or AC across any of those caps the ones that got it are done for.

And if you don't take that into consideration, you may have headaches in the future. I realise it is difficult to throw away a "new" capacitor. But they are really not that expensive and there is security in knowing that they are new, and not stressed.

Zsuttle · #5 07-12-2018, 08:43 PM

Yeah, today I purchased new electrolytics for all but one of the caps.(The only two that tested good were either before the diodes, or not in the power circuit.) Since I elected to restuff, it should be fairly easy to replace them without unsoldering the whole can, just cutting and resoldering the leads. My parts store didn't have some of the values, so I'll have to make do with a few caps that are higher value (eg a 150uF instead of a 120uF) but it should be alright until I get permanent replacements.

Zsuttle · #6 07-12-2018, 10:48 PM

Well this is intresting, the tubes failed to light, but then I found out that the grounds on the caps weren't connecting properly. After a quick fix, still no high voltage, but all of the tubes were once again lighting properly. When I test the Caps after a quick power on they test alright, but after sitting for some time they test way out of specs. What keeps blowing my caps? How do I troubleshoot this? Both of the diodes appear to have shorted once again as well.

timmy · #7 07-13-2018, 09:36 AM

Start from scratch with the schematic. There are 2 diodes, maybe one was put in backwards. The grounds go to different places so they cannot be tied together. IIRC one cathode end of one diode goes to the ballast, pin5 , and the other to pin 4 of the ballast provided you are using the correct ballast . The cathode end of the diode going to pin 5 now continues to the positive end of the second diode. Check that schematic it's all there as it could be a simple mistake or a wire in the wrong place. I have 7 of these sets and had my share of stupid mistakes.