If the three LEDs didn't light up during your last attempt yes. To not light up either one or more of those are broken, or there is a connection missing in their chain, or that K170 does not bias them. Do you have a 40W incandescent bulb to wire in series with the primary for current limiting like a dim bulb tester to save reworking on parts in case something is still wrong?
Your DMM has enough voltage in diode test mode to light up a red Led? If yes you can check them out on board one by one. It's a good opportunity now that the board is turned over.
I'll check the 40W bulb (60 too much?), no they didn't light up and I've just found a link missing between two of them, fixed it and now I have 1.85v across both Rset.
Still have 9.98v on one side and -23.4v on the other so switched off immediately.
Still have 9.98v on one side and -23.4v on the other so switched off immediately.
Mosfets are double inspected for correct type numbers in their places, yes?
Yes
Your DMM has enough voltage in diode test mode to light up a red Led? If yes you can check them out on board one by one. It's a good opportunity now that the board is turned over.
It does but I found the LED issue.
Once again thanks for being so patient and spending your time helping.
Yes
Your DMM has enough voltage in diode test mode to light up a red Led? If yes you can check them out on board one by one. It's a good opportunity now that the board is turned over.
It does but I found the LED issue.
Once again thanks for being so patient and spending your time helping.
60W bulb maybe not as fast in protecting just a preamp but still offering that useful glow sign and enough current limiting.
Anyways, you now solved the positive rail side over current. Congratulations, that one was the most eventful issue.
The negative side obviously is not regulating to -10V spec. Rset drop in the negative is healthy. No over current there too. Negative side's Mosfets Vgs check first. About 4V between pins 1&3 is healthy. Then the negative side's BJT transistor's Vbe (pins 2&3). Around 0.6V is healthy. Lastly when powered down, check all negative PSU side's K170 BL RDS. Pins 1&3. 30-40 Ω is normal. Inspect the relative PCB area for missing links or missing eyelets. Visually first and when in doubt with the DMM's continuity buzzer. Rework if necessary. Replace any semiconductor from the above list that still does not test right.
Didn't get anything like 0.6v on the bc560, nearer 3.4v, the drop on the Rset on that channel is 0.4v
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