with 22,8V supply, found 3 boards no behaving as supposed
Any ideas what to look for next?
#1 Check Q3, correct type, BC556 or any other PNP. Base-eimtter = 0.65 V? J1 and J2 are shorted? DZ1, correct and the right polarity?
#2 Something is not connected, could be the opamp inputs? R9?
#3 Q3? DZ1?
Since you have working units also take a real good visual inspection of the faulty ones, parts, placement and soldering.
You have not by mistake connected DC with the wrong polarity? If yes, you will most likely destroy the Q3 and sometimes the opamp.
first problem solved.
#2: R12 not properly connected
just addes some more infos on SSR1 and 2 boards for trobleshooting
Where should I look next?
Just for my understanding, the faulty regulators have never worked?
#1-3 LM329 is OK that's good.
#4-5 LM329, check
#1-2 Q3 OK? Q1 and Q3 are they really a PNP transistors
You have never by accident reversed the power supply? => destroyed regulators
Base - emitter voltage of all transistors? Should be 0.6-0.7 V
Thanks a lot
Indeed , some of them had been accidentally shorted.
I replaced LM337 and the nearby100uF in #5, but still no joy.
Checking LM329 by replacement or is there an easier way?
All except #4 deviate in Q3 Vbe, see attachment.
If you have connected with reversed power supply then you will destroy the regulators. Have you ever had the correct output voltage? The SSR02 seems to be very dead.
Notice that pin 4 is the supply pin for the SSR02. Consult the schematics.
I think we'll have to concentrate on the SSR01.
Voltage across the DZ1?
these are the remaining few out of a bigger batch
They never made it to the correct voltage. One SSR 02 was acc shorted.
DZ1 voltages mostly drop during measuremet towards 0V. But I can measure both DZ sides vs GND , whrer they show 13v and 19,5v.
If you have mounted 6.8V zener then no current will flow through it so the opamp is fried. Did you mount it correctly or have you reversed the supply voltage? Wrong polarity => dead opamp.
I think you should concentrate to look at number 3 to 5.
Notice that LM329 is turned around in SSR02 (see schematics) so pin 3 is interesting to measure.
The opamp has supply connected to pin 4. (see schematics)
Do you have tin on J1-J2?