Help identifying blown component in Dell PSU.

[roadrash]

I have just stripped down a PSU in a dead Dell Optiplex 200 and I found a component that has is front blown right off so I cant see what it is. It is mounted on a little piggyback board on top of the main PSU. No luck finding a Schematic either. Can someone recognise what this component is?

[Per Hansson]

Re: Help identifying blown component in Dell PSU.

Show the whole board, top and bottom, how is it connected to the PSU main PCB?

[roadrash]

Re: Help identifying blown component in Dell PSU.

Thanks and here are some more pics of the supply

[Per Hansson]

Re: Help identifying blown component in Dell PSU.

If my eagle eyes are right this is a Lite-On PS-5141-2D2 Rev

The board looks like a 5VSB board.
I would hazard a guess that the small Taicon cap is bad and has caused this failure.
But it could also have been a large power surge.
No idea what the original component (IC600) was.
But it looks easy enough to just wire in any 5VSB supply in it's place.
Is it wired up directly to the main rectified DC voltage in the main PSU?
And do you have that up? (Should be 155VDC with 110VAC)

[PeteS in CA]

Re: Help identifying blown component in Dell PSU.

roadrash is in the UK, so his line voltage is something like 240VAC. It has a 50/60 Hz passive PFC inductor.

The date codes on the PCB and magnetics indicate that this PSU was manufactured around early April, 2001. It's old enough that replacing it entirely - or re-capping it - should be considered, but looking at that Mini-Fit Jr. type connector, I think that might be a custom pin-out rather than standard ATX.

The Standby circuit is of the flyback topology, and the switch device is IC600. That means IC600 may have been a Power Integrations TOPSwitch, perhaps a TOP200. But, IIRC, STMicro had a competitive product. Fairchild Semiconductor may also have developed a competitive product.

[Per Hansson]

Re: Help identifying blown component in Dell PSU.

roadrash is in the UK, so his line voltage is something like 240VAC.

Ah, had a brainfart, same as here then.
So it will instead be: √2 X 230 = 325VDC

[roadrash]

Re: Help identifying blown component in Dell PSU.

Thanks for that info Per-Hanson you 100% right iy is a Lite-on PS-5141-2D2.
It sounds like you are quite familiar with these Dell/Lit-on PSU's. Ironically I have 2 old Dells that psu issues. This one I will need to fix as even a second hand one (if I can find one) are crazy prices so I will have to re-cap it or whatever I have to do to sort it. This other dell I have is working but is doing the Dell "orange light of death" (OLOD) which means it too has a psu problem and it refuses to boot up. I will discuss that one in a different thread though.

Your right as well PeteS I am on 240v mains here and in the U.K. By the Dell have there own proprietary type of ATX connection (see attached pic). Lots of people get caught out by this plugging in standard ATX psu's and they go POP. Luckily I noticed the wire colours were in different positions and some like the green [PS-on] wire were missing and I checked on-line and found Dells were different to normal ATX.

I did remember reading somewhere that some Dell psu's had problems with MOSFET's is this what has blown? I did try searching again for a Schematic or even a pictures of this psu somewhere just to see if I can find out what this blown component is but no luck.

[R_J]

Re: Help identifying blown component in Dell PSU.

You did'nt see the blown off part in the supply somewhere? It might still have part of the number on it

[roadrash]

Re: Help identifying blown component in Dell PSU.

I did have a good look round for it but didn't find anything maybe it was in lots of small fragments.

[R_J]

Re: Help identifying blown component in Dell PSU.

You might need to draw the primary circuit, It does look like one of those topswitch ic's and not just a fet. going by the 2 diodes across the primary etc.
Looks like it had bad solder connections and then maybe arced across 2 pins

[jiroy]

Re: Help identifying blown component in Dell PSU.

If Hansson is correct about this component is labeled IC600 , then it would be a variant of the kia431 series , but in a more powerful package .
In a Dell power supply PS-5251 , ic600 is a KIA 431A , which is a programmable shunt regulator diodes .The component could be also a XX7805 (+5v ) or a XX7905 (-5V) . But , it could be also a reference X regulator transistor to produce both voltages .

[stj]

Re: Help identifying blown component in Dell PSU.

it's a switching regulator,
looks like it probably was a topswitch.
they do blow when the startup cap fails.
https://ac-dc.power.com/products/pro.../topswitch-ii/

[roadrash]

Re: Help identifying blown component in Dell PSU.

Yes it is IC600. Thats brilliant work everyone working all this out from so little info. Getting close to finding out what it is now hopefully. If your right about it being one of the switching regulators on your list stj then surely its the TOP227YN which is TO220 case for 250v and 50w (original psu PS-5141-2D2 was 146w).
Can you point out the startup cap to me you say is suspect and I will remove it and test it. (sorry for my ignorance I'm still learning)

[roadrash]

Re: Help identifying blown component in Dell PSU.

I have removed the blown component (IC600) and taken some pictures of it in case it gives any more info.

[jiroy]

Re: Help identifying blown component in Dell PSU.

If this is a one of TOP221 to 227 series , its control pin ( c ) should be driven by the output transistor of a optocoupler . I don't see an optocoupler on the board , can you affirm ?

[stj]

Re: Help identifying blown component in Dell PSU.

that's just an example schematic, i'v seen loads of them just use an extra winding on the transformer.
i used to repair sattelite receivers full of them.
when the cap dries up they sit and pulse for a while creating a ticking sound - then BANG, your TOPswitch is toast!

RoadRash, check the brown Taicon to the left of it.
(and dont lose the ferrite bead on pin1)

[roadrash]

Re: Help identifying blown component in Dell PSU.

The Taicon 50v 47uf cap seems ok. I connected it to my component tester and it didn't say it was bad. Here are the results of its test.

tests as 47.26uf
Vloss=.8%
ESR .8 ohm

[stj]

Re: Help identifying blown component in Dell PSU.

well it could have just been age.
specially if the heatsink isnt all it could be.

[roadrash]

Re: Help identifying blown component in Dell PSU.

So what component do you recommend I use to replace this blown one and what is the ferrite bead for?

[stj]

Re: Help identifying blown component in Dell PSU.

ferrite bead is for stability.

no idea on the part number, but it's logical to take the one with the highest capability.
you may be able to salvage one from an old cable or sat box.