Motorola TS-4J

[Zsuttle]

Originally Posted by bandersen

Also I'm wondering about the values of the caps you're using. There should be a 140, 120 and 100 uF cap in the B++ supply circuit - nothing in the 10-20 range.

Yes, I recognise that the B++ power supply doesn't use any, however upstream in the audio circuit, the electrolytics are getting blown because they connect to the B++

Originally Posted by EdKozk2

I noticed that C-45 in the Sams schematic you posted does not match the Motorola factory issued schematic for a TS-4J late model. The ground end of C-45 should be connected to the floating B- line, not chassis ground. Also if you are using an original metal can ballast, make sure that it does not have any internal shorts. Remove the ballast if you have to, and check the pins for proper continuity and resistance. Your set is supposed to use the latter ballast, as shown in the schematic you posted. A ballast with internal shorts will cause all kinds of problems.
Ed

I'm using a glass ballast resistor that came with the spare chassis. It matches the pinouts of what I need. Which schematic would be the correct? I saw there was one on the ETF website that I think is more correct.

I can't check it today, (Adding a new rack to the workbench) but I'm almost positive I connected the output of the capacitors directly to the chassis. This whole floating chassis thing is a real pain in the neck.

[bandersen]

Definitely do not connect anything to the chassis.

Originally Posted by Zsuttle

Yes, I recognise that the B++ power supply doesn't use any, however upstream in the audio circuit, the electrolytics are getting blown because they connect to the B++

Ah, that's weird. What caps do you mean exactly? There are two electrolytics in the audio circuit and neither goes to B++.

If you mean the 20uF cathode bypass on the audio output tube, it should only have about 9 volts across it. Perhaps that 25L6 has a short or is miss wired ?

The other is a 10uF in the FM ratio detector that should only have a few volts across it as well.