expenriencing psu common mode latch up...I presume

[flaheu]

Need your help with one.

Background of my problem:
http://www.groupdiy.com/index.php?topic=52472.msg669098#msg669098

Is there any way of implementing an anti latch up on my dual psu ?

 

[moamps]

Hi,
did you check your -24V PS alone using a dummy load?
Milan

 

[flaheu]

Hi,

Yes it tests good alone.
I have changed for a new one and it's still not ok.
I should maybe make the current limiter a little slower (AMEK mod) by putting a 2200uf between pin 2 and 3 of the ua723 regulator.
When I use my dual lab 0-30V (2A) it works like a charm, but of course this one is current limited.

Any suggestions welcome, I'm a bit desesperate here, that thing is making me nut 

 

[moamps]

Hi,
IMO, there is no overcurrent or overvoltage latch installed (do you have the schematic for the PS?), so I would first measure voltage on the current sense resistor (the biggest one, R2 maybe) and calculate the output current.

At the end, if you are sure that all your wireing is Ok, you can baypass the current limit by placing a 3A fuse (slowblow) over the current sense resistor and see what will be happen.

Regards,
Milan

 

[JohnRoberts]

When supply is latched up what voltage do you read on -24?

can you turn on just the -24 supply?

JR