FSP400-60GLN worth fixing?

[Behemot]

Re: FSP400-60GLN worth fixing?

Pretty much all of those GLNs have the same problem. But good I finally know where exactly it is. I just thought the diode is overloaded and having huge losses - clearly the problem was connected with +5 V SB power as some PSUs I've seen were good, some not as some PSUs were loaded more, some less.

But anyway, the worst problem is the diode heats too much, this si what kills the caps. Usually all caps on +5 V SB are bloated, often other caps in the PSU are bad too. Crapxons mostly.

[everell]

Re: FSP400-60GLN worth fixing?

shit design.
dm311 can probably pull a lot of current given it has an integral fet.

and as you say 1n400x is too damned slow.
it should have been uf4007 or better.

Its not the design......its the parts being used. This is the same basic design I used to modify the Bestec ATX-250 12E mobo killer. The design with good parts works well.

[Stefan Payne]

Re: FSP400-60GLN worth fixing?

Stefan Payne: Pentium4 wrote a few posts down that it's normal, even brand new the coil has this color...
I think he is correct as I can see that the core in mine is not darkened...

Don't be sure about that.

I've heard that with some FSP PSUs around 2006 or 7 there were problems with the PFC coil due to manufacturing errors...

And those problems were mostly around 400W (-100W/+150W)...

[stj]

Re: FSP400-60GLN worth fixing?

shit design.
dm311 can probably pull a lot of current given it has an integral fet.

and as you say 1n400x is too damned slow.
it should have been uf4007 or better.

[everell]

Re: FSP400-60GLN worth fixing?

The burned area you see is under the feedback voltage diode D41 (1N4007). The filter capacitor for this feedback voltage is C15 the Teapo 47 uF/50 volt. If the diode was leaky due to general purpose diode being used at switching frequency, it could have killed the capacitor. The capacitor measured about 40 nF and esr beyond 99 on my blue esr meter. This feedback voltage provides the power to operate the DM311 chip. Whether the diode can't handle the frequency and killed the capacitor.....or the capacitor went bad and caused high current in the diode.....either way the power source to the DM311 was obviously causing problems. Thankfully I found and corrected this problem before applying power, and the 5vsb now works.

[Behemot]

Re: FSP400-60GLN worth fixing?

This is Fortron GLN, don't tell me you see it for the first time. There are multiple threads about this wonder.

This is no bug, it's a feature

[stj]

Re: FSP400-60GLN worth fixing?

that's got some nasty heat marks under one of the diodes.
is it over driven or was it faulty?

[everell]

Re: FSP400-60GLN worth fixing?

I have an Antec Basiq BP500U which appears to have the same pc board as the FSP in this post. In looking at the 5vsb circuit, this one has some interesting components. The snubber diode D42 was a 1N4007 1kv diode, but a low frequency general purpose diode. So I replaced it with a MUR2100EG 1kv high speed diode. The feedback voltage diode D41 was also a 1N4007 1kv low frequency general purpose diode. This circuit only produces 12volts to 18 volts. So 1kv seems like overkill, or perhaps they were just using 1N4007 everywhere. So I replaced it with a 1N4935 high speed switching diode. The feedback filter capacitor C15 Teapo 47 uF/50 volts was open. A leaking feedback diode could cause this capacitor to go bad. Perhaps you should check these components on the FSP power supply.

[Per Hansson]

Re: FSP400-60GLN worth fixing?

budm: Thank you very much!

Stefan Payne: Pentium4 wrote a few posts down that it's normal, even brand new the coil has this color...
I think he is correct as I can see that the core in mine is not darkened...

Behemot: Yea I used the wrong capitalization for "Mega"

Uniballer: I agree with you, I was not going to fix it as I wrote in my original post.
But more due to curiosity I changed my mind as I was ordering some stuff from Elfa anyway.
So felt I can get the main bulk capacitor and see how it goes.
If it wont work I can just take it out and use it in something else...

[budm]

Re: FSP400-60GLN worth fixing?

2 mΩ is miliohm here where I live. Mega is M.

He uses the wrong 'm' in his typing that why I said 2M (Mega) Ohms because I know the meter does not display 'm'. His meter will show 'M' not 'm'. 'm' is also milli here.

[Uniballer]

Re: FSP400-60GLN worth fixing?

I have a hard time committing to fix power supplies like that since you can get a "refurbed" (or working pull) Seasonic SS-350Ex on ebay for <$20 w/ "free" shipping. I know it is "greener" to fix what you have, but turd polishing gets frustrating.

[Behemot]

Re: FSP400-60GLN worth fixing?

"2mΩ" 2 Mega Ohm, that means it was already bad since it is very low Ohm resistor to start with.

2 mΩ is miliohm here where I live. Mega is M.

[Stefan Payne]

Re: FSP400-60GLN worth fixing?

I have 2 of them , with the same problem. The pfc coil is completely burned. The value of R44 is 2ohm marked 2R0

Interesting that that happened to other FSP PSUs as well...

Let me guess: around 400W they have, both?

[budm]

Re: FSP400-60GLN worth fixing?

"So the original fusible resistor has failed open "saving" the DM311." No it is for saving the power supply from more damages due to shorted out DM311, if the resistor was not there when the IC shorted, you can have fire and badly burnt board. We are talking about shunting the >160VDC to ground through the shorted MOSEFT inside that SMPS IC, you can get very nice sparks and fireworks. You should check the RCD snumber network.

"Then I put in a _regular_ 2Ω resistor: RK73H2BTTD2R00F
And it blows up more spectacularly since it's not a fusible resistor.
And the DM311 was already shorted but was now allown to explode since the resistor did not burn up fast enough." Correct.
I also see some bad solder joints, so you may want to inspect the board real well.

[Per Hansson]

Re: FSP400-60GLN worth fixing?

Ahh ok, now I understand.
So the original fusible resistor had already failed open "saving" the DM311.
Then I put in a _regular_ 2Ω resistor: RK73H2BTTD2R00F
And it blows up more spectacularly since it's not a fusible resistor.
And the DM311 was already shorted but was now allown to explode since the resistor did not burn up fast enough.
Thanks for setting me on the right track
Do you think anything else is damaged from this or it might be ok with just a new DM311 & fusible resistor?

[budm]

Re: FSP400-60GLN worth fixing?

Here is the spec of the SMPS IC and how it is used.

[budm]

Re: FSP400-60GLN worth fixing?

2R0 value is the correct value for that circuit, it is because the IC was already shorted and took out the first resistor, it is not bleeder resistor either.

[Per Hansson]

Re: FSP400-60GLN worth fixing?

Yea but I replaced it with a 2R0 resistor as that is what "cxg" wrote in the second post above that it was supposed to be.
I did not realize it was a fusible resistor though!

[budm]

Re: FSP400-60GLN worth fixing?

"2mΩ" 2 Mega Ohm, that means it was already bad since it is very low Ohm resistor to start with.

[Per Hansson]

Re: FSP400-60GLN worth fixing?

budm: I'm not sure, I measured 2mΩ but that was in circuit.
With it out of circuit now I can't measure anything.
I tried cleaning it but it's impossible to read what it is rated for, markings have been burned off...

Thanks for the annotated picture, you edited it in after my reply above