Indeed - the opto is the one with the green mark and I traced the signal to one output pin of the LM339. I know what the inputs are, I need to check what happens there.

Because it says 5ms before "loss of regulation". I'd be tempted to think that this signal comes from the secondary and not primary. The main switching IC might have a feedback signal that goes back to the main logic and tell "I am about to drop the voltage".

"simple" is a big word 🙂 Thanks for now!

there are some jumpers at the back, you see them closer to the optocouplers. I suspect they set how the logic works. I don't see anything programmable on that PCB.
Yes, Global AC Fail doesn't do anything to the secondary, it monitors (I guess) the 390V DC and sends a "Global AC Fail" signal when it goes below a certain level to instruct the device connected to the PSU to take action.

OR - it could be one of those DC modules sensing the DC voltage in and reporting it back to the logic.

So far I haven't been able to see where this logic is getting the signal...

It's a modular power supply, it can be configured from Digikey etc to whatever you want in terms of currents and voltages.

https://www.xppower.com/product/fleXPower-Series

I don't think the load is the issue here - but I can try, thanks. The idea with the AC Global signal is that if the PSU has a compromised primary, the standby electronics will sense it and won't even try to turn on the secondaries - and will also log/display the issue.

"Global DC" logic works. There is an LM339 where the logic happens which I understand is a voltage comparator....

Hi all

I've fixed a couple of FleXPower X7 power supplies. Since they have some logic outputs, I went to test them to make sure all was in order.
"Fan Fail" would work when the fan is manually stopped.
"Global DC" would change state when I manually adjusted one rail beyond 10%

"Global AC" doesn't seem to do anything. To test, I power up the PSU and then I remove power. The 5VSB and Aux rails remain active for quite a few seconds after power is removed. I see the rails collapsing but there is no change in the "Global AC"...

No need to apologise, thanks for keeping the forum running!

A post I added yesterday seems to have been lost in the Ethernet. Google shows it but it directs to a different one.

It was supposed to be here: https://www.badcaps.net/forum/genera...con-tmv-series
But now a different thread shows up. The post is not listed in my account anymore.