Jan 5, 2017, 7:09 PM
Post #3 of 14
Re: [jts1957] Help me diagnose and fix a TV-like power supply..
[In reply to]
Thanks for your advice!
R5006 & R5007 are correct. I measured 180k on each (well, 183k and 181k) to be precise. I might have to revisit that, one of them (R5006) took a long time to settle down, whereas measuring it on another (working machine) gave 180k immediately. Does that suggest anything to you?
All the other resistors in the high voltage part of the circuit (feeding TS001) measure correctly, and match the working machine. But the input of TS001 is dead.
C5005 looks OK, no bulging or other unpleasantness visible. Someone (on another forum) suggested changing C5006. Does that make sense to you?
STK pins 11-14: 0.4 ohms.
STK pins 11-15: 0.4 ohms.
These measurements were taken with the STK removed from the circuit. I think it is blown. I fitted another one from a working machine and it didn't work either. Then, when I returned it to the working machine, the "working machine" became another "dead machine". So I guess the board in the first machine has something wrong with it that is killing the STKs. On the board, the readings for 11-14 and 11-15 are all over the place, in the 15 - 20 Meg Ohm range.
I'm confused by your statement that 315v is normal for pins 14/15. The schematic is showing 7.4v. Am I missing something?
This IC needs some voltages or resistances applied to "program" it, right? Do you know how it is setup for a specific output voltage?
(This post was edited by JonB on Jan 5, 2017, 7:17 PM)