Samsung 931BW no power

[s_henya]

Hey guys, got this monitor for repair yesterday,

When plugged in there is no power, no led light, but if you
listen you could hear there is a problem whith the power suplly,

opend the case no caps are bulged, fuse ok, there is a shorted "big" diode
SR310.

what else should i look for, before ordering a replacment,

i will upload pics later today, and i'll check all the caps anyway.

anyone know this power suplly, how to check voltages when open and disconnected from logic board.

thanks,

[selldoor]

Re: Samsung 931BW no power

Have you read this post
https://www.badcaps.net/forum/showth...ighlight=931BW

[s_henya]

Re: Samsung 931BW no power

now i have, :-)

the problem is bit diffrent, all of my caps on power board seems fine,

but the diode is shorted,

never saw a doide that big shorted, that's why i asked....

[selldoor]

Re: Samsung 931BW no power

Ok - waiting for the pictures thought it might be useful for checking voltages.
You normally need the logic board connected.

[s_henya]

Re: Samsung 931BW no power

sorry for the delay, but here are the pics,
had to shrink them...
checked all caps esr and capacitance, all good,
ill search the diode, localy if i wont find it i'll have to order from ebay.

any suggestions...

[Rtech]

Re: Samsung 931BW no power

I find that these standard Diode types (DO-201),are used on quite a few different Psu/Inverter Boards, and tend to fail more than the one that is normally screwed to a heatsink.I suppose there are various reasons for this,but when i see them on a Board, they are always one of the main points of interest in the the fault finding procedure.

[s_henya]

Re: Samsung 931BW no power

couldn't find the diode SR310, but i could find ct pr3002 or 1n54004
the thing is that there are 2 diodes in parallel the shorted one, and another one just like it which is good, if i would replace the shorted one with a substitue will it still be ok?

[Rtech]

Re: Samsung 931BW no power

I always change both, as you do not know what caused the the failure, and the second one may well be weakened.But the choice is yours.The replacements need to be 'fast recovery' diodes, and if so and current etc is fine,(I have not checked your choice),then all should be fine.

[s_henya]

Re: Samsung 931BW no power

i decided to buy the originals from ebay, 10 diodes for 5 dollars.

i will update as soon as i'll get the shipment.

[s_henya]

Re: Samsung 931BW no power

hey, iv'e got good news,

recieved the diodes today,

replaced both as suggested, works as good as new!

thank you all for helping!!