Power supply from dot matrix Fujitsu printer

[microcont]

Hello guys, here i have an PS , from Fujitsu old printer. It's seems good, all caps are fine , and there is zero damage, on board , and it must work , but it dosen't.
I can't find anything for this PS, so lets try here, i measured voltage on primary side and its all fine, but secondary i don't know 0 volts at everything heheh.
I tried something jump as "PS ON", tried to put load on output terminals, try guess nothing! ,It seems to have some "Photothyristor Coupler"

http://pdf1.alldatasheet.com/datasheet-pdf/view/43502/SHARP/S22MD1V.html

, and some pic.
Thanks hehe

[stj]

Re: Power supply from dot matrix Fujitsu printer

get a datasheet for that str series regulator,
see if it uses a startup voltage or pulse.
most old crappy switching regulator chips either use a small startup cap - 4.7-47uf or a resistor to the rectified mains to kickstart the chip.
find them and destroy them.
i mean test or replace them!

[budm]

Re: Power supply from dot matrix Fujitsu printer

There are two start up lytics caps, one is close to the heat sink, and another one is to the right of it. This is an always on power supply, no PS_ON CONTROL.

[microcont]

Re: Power supply from dot matrix Fujitsu printer

So, I need to change startup lytics caps?

[budm]

Re: Power supply from dot matrix Fujitsu printer

Do you have cap meter that can check the capacitance and ESR? if not, then you can try changing the caps.