FSP400-60GLN worth fixing?

[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.

[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?

[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.

[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.

[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.

[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...

[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.

[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?

[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

[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.

[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.

[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)...

[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.

[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?

After a recap of those Capxon output capacitors, the power supply refused to turn on. My power supply tester with LEDs indicated that 12 volts and 5 volts was trying, but the 3.3 volt rail was not doing anything. Output diodes measured OK. So I drew a schematic of the 3.3 volt circuit with which to do some serious troubleshooting. To my surprise, Diode D35 had never been installed. Don't know how it ever managed to work, but I bet someone had lots of squirrely memory issues.

So here is the schematic....to help others troubleshoot the 3.3 volt circuit on this power supply. Also a picture of the location of the missing D35 diode.

[cxg]

Re: FSP400-60GLN worth fixing?

Dear Per Hansson
Im sorry for what happened to your power supply board but the value of the resistor is right. Im posting you a picture of that part of the circut and you can see yourself.

[Behemot]

Re: FSP400-60GLN worth fixing?

Yeah I ca confirm 2 ohm, got a 350W version right here with all caps (but primary) bloated.

[Per Hansson]

Re: FSP400-60GLN worth fixing?

cxg: It's all ok, I just did not understand that it needs to be a fusible resistor, and not a standard resistor...
The DM311 was most likely as deduced by others shorted before I started.
So when I replaced the fusible resistor with a normal resistor it was pretty much like bypassing a fuse in your house.
Lots of fireworks
Of course if the DM311 had been fine it would have worked with the normal 2ohm resistor I put in...

[Per Hansson]

Re: FSP400-60GLN worth fixing?

What's the voltage drop of a 1MΩ resistor connected to the ~330VDC line?
Because I thought the 1MΩ resistor connected to Vstr on the DM311 was bad.
But when I desoldered it measured fine on one multimeter, but no reading on another...

If I remember right I think I saw ~70VDC on Vstr before desoldering the resistor.
5VSB was not live...

[Behemot]

Re: FSP400-60GLN worth fixing?

Depends on what else is there. If nothing, than it has drop of 330 V. If something else, than <330 V.