Fortron FSP300-60ATV repair

[everell]

My story starts out last October when a friend gave me a Fortron FSP200-60ATV which was "burned up". Yes it was. See attached photos.

The two transistor 5vsb circuit was dead. I made an attempt to fix it, but only succeeded in blowing out both transistors again, and the fuse. The culprit on this power supply seems to have been a zener diode which was supposed to have protected the 5vsb from going overvoltage. Instead, the zener went overcurrent, burned, shorted, then caused the rectifier in that circuit to burn. burning both the diode and the pc board. Other parts were also damaged. Due to the burn damage, I decided to use this board for spare parts.

[everell]

Re: Fortron FSP300-60ATV repair

Last week I got a Fortron FSP300-60ATV, same pc board but not burn damaged. Symptoms were same - 5vsb dead. The main switching transistor was shorted, and the other transistor was blown apart.

I found this power supply to be most interesting. The brand - Fortron - is the favorite of i4004. The 5vsb uses the two transistor circuit design, but does not have an aluminum "critical" capacitor in the usual location. So this circuit should not have gone overvoltage. Again, the main switching transistor was shorted, and the other transistor was blown apart.

I decided that since replacing the critical capacitor would not be a fix (it doesn't have one), and due to bad transistors and probably other parts bad, I installed my DM311 mod. On power up, the 5vsb still did not work. Troubleshooting found the problem to be a leaky diode D9 on the secondary side of the 5vsb transformer. Now the 5vsb was up and running.

Next, I removed the two capacitors which form the pi filter for the 5vsb. Both are 1000 uF/10V OST. I was going to replace them with new Nichicon PW 1000 uF/10V which measured esr = .06......but the two OST capacitors both measured esr = .02.......so I left the OST capacitors in the circuit.

Voltage measurements after repair:
12v = 12.16 volts
5V = 5.18 volts
3.3V = 3.35 volts
5vsb = 5.23 volts

Photos attached to show repaired board before putting it back in case. Also photo of back side of transistor blown apart.

[xchequer]

Re: Fortron FSP300-60ATV repair

That looks like a great mod! I had a burned up power supply just like that, that I gave to a friend.

[yanz]

Re: Fortron FSP300-60ATV repair

nice work, everell!

[everell]

Re: Fortron FSP300-60ATV repair

One more photo showing pc board back in the case. Modification can be clearly seen inside the case.

[everell]

Re: Fortron FSP300-60ATV repair

I have a second Fortron FSP200-60ATV, no 5vsb just like the first one, but not burn damaged. I checked ZD1 the zener diode across the 5vsb, and it was shorted. That makes two Fortrons, same model, same problem. ZD1 is located next to diode D9. I removed the diode, applied power, and everything works fine. In my opinion, this is sufficient proof that putting a zener across the 5vsb is NOT a good solution for 5vsb circuits that go overvoltage. It simply shorts zener diodes.

In the Fortron FSP300-60ATV there was no zener installed at the ZD1 location. The diode D9 was shorted and took out the two switching transistors. So looks like diodes D9 and ZD1 are a good place to start when troubleshooting these two models.

Two of the psu had shorted/blown switching transistors. I had email from pieti requesting information - his transistors were blow beyond recognition and he needed part numbers. They are:

FSP200-60ATV: Fairchild FPQF 3N60 and H945

FSP300-60ATV: ST P3NC60FP and H945

The 5vsb circuit looks the same for both models. I tried to repair the two transistor 5vsb circuit on the first psu I worked on, but only succeeded in blowing out the transistors again. Repairing this circuit is tricky! So I put the DM311 mod in it and have had no further problems.

[cagiva4ever]

Re: Fortron FSP300-60ATV repair

hi !

i have 2 broken FSP psu's: FSP200-60ATV(PF) and FSP350-60PN(PF)

the fsp200 i need to fix desperately as its in a Acer Desktop PC that i use at my mom's house (no other PC there).
Another problem is that i am not in a situation or at a location to buy new same model PSU or a used1 as they dont exists here where i live, so i have to fix what is broken to keep things going-rolling. ordering new1 would cost me nearly 100 euro's or even more.

problem with the fsp200 is that it wont power up PC, when Power button pressed ON ,the PSU will only "humm" for a second and then dead (Fan wont spin at all at any stage). to get same reaction i need to take the powercable of the wall and let the PSU be unplugged for a while to get even the 1 second humm at Power-Up.

i have also tryed the PSU separately, meaning all cables taken of the Motherboard, and problem is still exactly the same. Cooling Fan wont spin at all and PSU shows no life at all.

Prior this problem PC worked wonderfully and while it hasnt been used i have had it OFF the wall, so no Lightning or any voltage spike problem causing this on our house electricity. at 1 day i just went for the PC and was about to Power it up and start using it ,and Nothing happened. Previous use had been working perfectly and PC was powered of normally etc and power cord taken of the wall at the end (because the PC gets usage once~twice a week at mom's so better take of the PowerCard to avoid Voltage Spikes etc Lightning strikes).



the fsp-350 is a free carbage picking find that i took for spares, and THANKS to this topic im starting to realise how bad quality PSU's these are.

i strongly think i see 2 small swollen electrolyte capacitors on it (fsp-350). another is next to the D9 diode and the another swollen Capasitor is about 2cm aside. both swollen Capacitors are TEAPO 35v 100uf.

now a nooby guestion i have to ask, is there only1 D9-diode and only1 ZD1-diode on this pcb design ? i would assume yes based on what i have learned in past 5 minutes, as i havent ever worked with PSU's before.


i will take some good photos from the fsp-350 pcb soon in couple days and post them on this topic if its ok to topic starter ?

also i will have a 4th look on the fsp-200 psu and see where the D9 and ZD1 are on it and if it has also swollen tiny 35V 100uf capacitors, as i didnt notice anything such or anything odd in it at previous times.


i would very very much appriciate Tech support etc help on this issue from Topic starter or other people able to help me.

bye
m from Fi

[everell]

Re: Fortron FSP300-60ATV repair

Still waiting for pictures. I located my FSP200-60ATV and have it handy as a reference if you have any further questions. Yes, any capacitors that are bulging are bad and need to be replaced. Also look for glue on parts which is turning dark brown or black. This indicates that the glue is becoming conductive and causing shorts or resistive paths.

You can use this thread as a place to discuss repairing your power supplies, or you can start a new thread for your power supply problems. Your choice.

Welcome to the forum. Fixing a power supply can be both fun and interesting.

[Longbow]

Re: Fortron FSP300-60ATV repair

In my opinion, this is sufficient proof that putting a zener across the 5vsb is NOT a good solution for 5vsb circuits that go overvoltage. It simply shorts zener diodes.

My opinion is that your conclusion is a bit hasty. This particular circuit may have other design problems, but the faulty zener is there to protect everything that is downstream, which it apparently did.

[everell]

Re: Fortron FSP300-60ATV repair

More "opinions" please

[DSTACY]

Re: Fortron FSP300-60ATV repair

Does any one have a schematic for this power supply?(FSp300-60ATV0 I cant find D9
I am first timer to work on power supplys but work on other things eletronic.

[everell]

Re: Fortron FSP300-60ATV repair

I started drawing the schematic of this thing about two years ago, but this is as far as I got. Perhaps you can add to it!

[cagiva4ever]

Re: Fortron FSP300-60ATV repair

Still waiting for pictures. ....

hi !

sorry, i havent been here for a while as i thought my try to get help was blank useless.

but now i can see that your active and here.

i have dismantled PCB from Case at FSP200 and i have tryed to look faults by my eyes but cannot see anything odd on it at anywhere.

apparently the FSP needs a 5v signal voltage from Motherboard to fireup, so i put a jumber wire connection to PSU Green cable and Black at connector block (PSU taken of the PC and Bench testing PSU separately)

with this jumper cable the PSU and its cooling fan still only like Blink, like 1 Fan rotation and thats it. with this im trying to say that most likely Problem is In the PSU and not at the Motherboard.

i dont know what do do next with my FSP200. any ideas ?

i do not have replacement 35v Caps or equivaliment for my FSP350, so i cannot fix it yet. my friend who is more PC geek than i said to me that FSP350 400V (iirc) BIG Caps 2 of them looked Swollen (as they dont have the Split grooves on top its hard to say, as they have like a sticker Tap on top and it can naturally be a Dome'ish shape anyway (?)

bye
m

[everell]

Re: Fortron FSP300-60ATV repair

As a quick check, use ohmmeter to check resistance of the diodes....the big ones attached to the heat sink on the output side. Typically they measure a low resistance, but a shorted one will measure ZERO ohms. It should be quite noticeable if shorted.

A shorted output diode will give the symptom you are describing.

[cagiva4ever]

Re: Fortron FSP300-60ATV repair

hi !

ive been out of internet for many months now, as no internet connection at home, so im using Library's connections once again these days @ village Library.

i have now managed to get a replacement ( used) better wattage PSU and it works. Problem now is that there is no Monitor Signal and Monitor doesnt work hence that.

maybe my OEM broken PSU did some damage to Motherboard or something, or something else (as i have tryed another working monitor)

i will try and find a used working Graphics Card to "replace" the Motherboards integrated1, and see if that cures the Monitors "No Signal" notification.

if some1 has ideas what could be wrong, please let me know.

meanwhile , as promised, i will now start posting good photos to here from my broken FSP350-60PN(PF) PSU as a data to this great topic.

that fsp350 is just a individual item i have found separately as a broken from scrap container..

bye
m

[hctan]

Re: Fortron FSP300-60ATV repair

Hi. what is the color code for R31 and R68 (unable to see clearly burn damaged) near the jumper (J 31) / fuse. Your help in this regard will be highly appreciated. Thanks.

[everell]

Re: Fortron FSP300-60ATV repair

I found my FSP200-60ATV but could not locate the FSP300-60ATV which I had some time ago. I found the J31 jumper you were referring to, but could not locate R31 or R68. I would suggest that you post a picture of your power supply and draw a circle around the resistors you need information on.

My power supply had a LOT of burnt glue which needed to be removed. I suggest that you remove any dark brown glue before attempting repair.

I think you are describing resistors in the 5vsb circuit. Is that correct? These Fortrons use a two transistor circuit which I have found to be very difficult to repair.

[hctan]

Re: Fortron FSP300-60ATV repair

Hi. Before that, i wishing all the christianity members a merry christmas. i hope the attached photos below can help me to solved the problem regarding the 2 burn damaged resister color code for R31 dan R68. Any help appreciated. Thanks.

[hctan]

Re: Fortron FSP300-60ATV repair

h

[hctan]

Re: Fortron FSP300-60ATV repair

Hi all members. my power supply's resister had burn damaged. so anyone can help me to find the resister color code for R31 dan R68. any help appreciated. Thanks.