FSP250-60GTV circuit diagram?

[Barf]

Hi,

I have an FSP250-60GTV ATX PSU that has failed. It doesnt respond to the PSU ON signal.

Internally, there is a very obviously burnt up high wattage resistor (which i believe from another thread about this model to be a 5v load), however, resistors dont often fail on their own, so im suspecting a semiconductor somewhere may also have failed.

Does anyone have a circuit diagram for this model? I dont have the value of this resistor and i have no previous experience working on ATX supplies, so will need the diagram to go on


Cheers

Martin

[everell]

Re: FSP250-60GTV circuit diagram?

Welcome to the forum. I looked to see if I had any power supply same model as yours, but do not. If you will post some pictures of the inside of your psu, then perhaps I might have something similiar. I do have a FSP-250 GTW, but it may be a totally different animal.

Where are you from? It is always nice to know where folks on this forum are from.....it is an international forum.

[Scenic]

Re: FSP250-60GTV circuit diagram?



i bet he's talking about this one.. (located in the bottom right corner in the above pic)

[Barf]

Re: FSP250-60GTV circuit diagram?

Hi Chaps,

Scenic, yes that does indeed look the beast! The unit i have has a smaller PCB attached to that heatsink top but otherwise looks the same. Yes, that is indeed the resistor to which i refered.

I would very much appreciate any advice on fixing this unit. Ive been a communications engineer for over 10years, but computers and especially their PS's are not my field at all (i can knock a linear supply up for anything you like, but SMPS's i have no idea!). From what i can gather this resistor provides a base load for the regulators to function?

So far my method of testing the supply has been to pull it from the PC and onto the bench, short the PS ON line to GND, and measure for output, of which there is none. The PS ON line is at aprox +4.8v. All lines read a sensible resistance to ground except the 5v rail which reads 7ohm (ive seen that mentioned before but sadly on a polish forum which didnt translate well)

The PC itself came from a local universities charity computer recycling project. I can take it back but not for a couple of weeks, and if i can fix it it will save me the drive. They are good guys who will swap it, but its the 'LN' version, very low electrical noise, which is excellent for my location (it will work beside a weak signal HF radio station), and they might not have another of this type (one thing i dont like about it though is the unshrouded conenctions to the IEC sockets, i might have to sort that. Manufacturer saving a couple of pennies per hundred units on heatshrink!)


Everell - sorry, not had time to edit profile yet, im near the city of York in NE England

Martin

[everell]

Re: FSP250-60GTV circuit diagram?

I fixed one similar to that a couple of years ago. That resistor you are referring to would "wiggle" very easily. The circuit trace on the other side of the pc board was very narrow, and had broken. As you moved the resistor back and forth, you could see the break in the circuit trace. The resistor is so big and has no mechanical support....the trace is so small and just couldn't take the movement of the resistor. I soldered some wire along the trace to add strength to the trace, and that fixed the power supply. So look for broken trace where that resistor feeds thru the pc board.

[Barf]

Re: FSP250-60GTV circuit diagram?

Everell, what were your symptoms on that one? I can see that the trace could break very easily. If the regulator for 5v cant see its load resistor, would that cause the whole unit to fail? I understand theres a 'power good' circuit, but no idea how it works!

[everell]

Re: FSP250-60GTV circuit diagram?

Symptom: dead

It was one of the first power supplies I ever fixed....just a beginner's luck fix because I spotted the broken trace.

If this opens the 5v rail, then the power good signal would be bad and shut down the power supply.

I don't know of any good source for diagrams. When I get really serious about fixing one, I draw out the schematic of the circuit I am working on. So I have several schematics of things I have fixed, but not "complete" schematics of anything. Most of my work has been done on Bestec psu, but I have done some work on Fortron/Sparkle (FSP) and other brands.

[Barf]

Re: FSP250-60GTV circuit diagram?

cheers, that sounds like the same symptoms!

I'll open her up again shortly and see what i can find.

Do you know if theres a 'primer' anywhere on how these supplies work? I could do with at least learning the basics of their operation

[Barf]

Re: FSP250-60GTV circuit diagram?

well, with it open on the bench, after a bit of wiggling of that resistor its started running. So im going to link out the PC tracks from that resistor to ensure that the connections good. It might not be the fault, but its a start

[Barf]

Re: FSP250-60GTV circuit diagram?

ok, so were having a bit of 'fun' here at Chez Barf with this PC!

A visit to the uni workshop resulted in a swap of PSU, for one of the same model, which worked in the lab during a brief check, but the machine died again later! It looks like the mobo was the cause.

The chaps at the uni are posting me a replacement mobo out (thats been thoroughly soak tested), along with a spare and its CPU to use as a reference to fault find the dead one.

Now, im worried that we could be getting into a 'fault loop' with each device taking out the replacement! I want to avoid that (cos i dont want to kill the new mobo!) so need a rough and ready way to load the PSU to prove its not that killing everything, or dying itself under load.

Im thinking of simply using a string of automotive bulbs, ie headlamps. The ones i have (for my car) are rated 55W. What would be a sensible load to put the 12v line of the PSU under to check its not failing when loaded?


Martin