ATX Hiper type R 480W postfixing problem

[harp]

The psu has initialy shorted 5vsb and few rounded caps...
I find short, there was big sb540 diode and one red small in glass no marking, from 5vsb rail to ground.
After replaced sb540 with sb560, I supose that this glass diode was zenner 5v1, so I put it there. Also replace mentioned caps. I was so confident that I put all in box...

All double checked, nowhere short is remaining, it has 5vsb and 5v ps-on now, but when power on, it briefly run (fan and voltage) and shutdown. This behaveour is repetable if again switch on. I do not use any bulb or toaster this time, nor any load.

I conserned about these glass diode, if I miss point...
Is it some changed in "modern" atx supply, say they need connection to mb or so? All before, they run naturaly when pson applied.
Any idea?

[CapLeaker]

Re: ATX Hiper type R 480W postfixing problem

Sounds familiar to me. Look at my PowerMan IP PSU repair, it’s a similar problem, probably not the same, but it will give you an idea. Check out the feedback optocouplers. Find the one that goes to the supervisor IC shutdown. If the pin is high in voltage, it’s in protection mode. Force a ground to this pin and the supervisor IC is disabled…
https://www.badcaps.net/forum/showthread.php?t=106011

[harp]

Re: ATX Hiper type R 480W postfixing problem

Thank you very much, I use your example for schortcut.
Two main caps are ok, bridge is ok, but found one (of three) optocoupler who on one side no reading at all in diode mode. After desoldering, one side is stay still open... so I now must find something simmilar.
https://www.tme.eu/en/details/ltv-81...output/liteon/

Before I plugin to mains, is there anything else to check?

[stj]

Re: ATX Hiper type R 480W postfixing problem

817 is a very common part

[CapLeaker]

Re: ATX Hiper type R 480W postfixing problem

check the voltage on each pin of the optocoupler on the secondary side to secondary GND. Then look up the spec sheet of the opto. Also clearer pics would be nice. 817's are pretty common as stj already said.

[harp]

Re: ATX Hiper type R 480W postfixing problem

Is sfh690b situable replacement?
https://cdn.badcaps-static.com/pdfs/...fe342584b2.pdf
I have a couple of it, or must find harder 817...

[stj]

Re: ATX Hiper type R 480W postfixing problem

cny17 may also match

the 690 looks good on paper, but the package is very small.

[harp]

Re: ATX Hiper type R 480W postfixing problem

check the voltage on each pin of the optocoupler on the secondary side to secondary GND. Then look up the spec sheet of the opto.

That supose to do after conecting the main... if not blow up.
But, what you mean with that, what I looking for?

I visualy traced place with burned opto, burn side is on primary side, and it is not for 5vsb. Shall I dig to try find why it die?

[CapLeaker]

Re: ATX Hiper type R 480W postfixing problem

See if the supervisor shuts the PSU down. The opto needs a certain voltage to turn on. Upload a picture of the secondary side with the supervisor IC. Let’s see what this thing is.

[harp]

Re: ATX Hiper type R 480W postfixing problem

I have a good news and a "good" news... which one first?
A good news is that I found pc817 from sharp, and a "good" news is that this opto has the same reading in diode mode as original, compared to original... I mean no reading on one side.

I connect on a dot side transistor tester, and with dmm monitoring other side... both do a brief reading, so it was both good.
I will return original opto on pcb.

Uh, I love working with device pluged in the main, I mean what can go wrong... right?

So, what next I lookin for?

EDIT
TL3842, LM339, L6561, NONAME 18 pin for fan

Previous repair on 5vsb
D7, ZD2, C18, C19
check all on secondary heatsink ok, and C20

[harp]

Re: ATX Hiper type R 480W postfixing problem

See if the supervisor shuts the PSU down.

Little help how to do that

[Per Hansson]

Re: ATX Hiper type R 480W postfixing problem

it has 5vsb and 5v ps-on now, but when power on, it briefly run (fan and voltage) and shutdown. This behaveour is repetable if again switch on. I do not use any bulb or toaster this time, nor any load.

Most ATX power supplies require a load to operate.
Please connect a few old hard drives or a PC mainboard and try again.

[harp]

Re: ATX Hiper type R 480W postfixing problem

Most ATX power supplies require a load to operate.
Please connect a few old hard drives or a PC mainboard and try again.

In my case, that "most" is my first atx who work like that...
Thank you, it work with mb connected, so this thread was false alarm to "most" people
I learn a lesson, and I will using it in future.
Thanks a lot

[CapLeaker]

Re: ATX Hiper type R 480W postfixing problem

That brown goo, I’d remove on sight. It goes conductive after a while causing corrosion and spells trouble. I guess I am late, but yes this PSU has no loading resistors ( like two 100 Ohms resistors in parallel) on the output that I can see. Per already mentioned that there has to be a load on it and this would have been the next suggestion. That’s why good pictures are always important!