LiteOn PA-6601-1A (600w) blows its TOP

[godonr]

Re: LiteOn PA-6601-1A (600w) blows its TOP

just checked back (never give up hope) to see if anyone was still messing with this. In 2011 I purchased some 551-PS2561AL-1-A optocouplers from Mouser Electronics. they were the lead bending type (surface mount). Ideally you want the DIP type, but the leads on the AL can be modified to work. The complete NEC part # is PS2561B-1. Good luck

[wasureppoi]

Re: LiteOn PA-6601-1A (600w) blows its TOP

It would appear that most of the components mentioned in this thread are readily available but the OPTO851 which is clearly marked NEC2561 and WK435 is negative to all searches.
Would you know what an alternative chip would be? I have gotten the same ohm readings on all of them - one I removed and four in the board side by side.
Any help would be most appreciated.

[wasureppoi]

Re: LiteOn PA-6601-1A (600w) blows its TOP

Hi godonr, Q856 is on the underside of the board, it's a small SOT-23 surface mount transistor, my guess is that when the TOP blows, it can cause a surge of voltage to damage the Q856. Also in my case, the surge also damaged OPTO851. I couldn't get the exact repalcement, but it seems fairly standard in specification so I fitted one from my spare parts which had the same pinout.

So after replacing U801, Q856 and OPTO851, I have a fully working PSU.

Hope you have the same luck.

Cheers

Jon Fuge

Please forgive I found the Q856 but what is the OPTO851?

Hi,
Forgive my ignorance. I have spent ten minutes examining under the board and still cannot find Q856 but gather it is a 3 legged chip. Would you be able to point me in the general direction? I have replaced my U801 and the TOP and can see the OPTO851 4 legged chip but what is that components name or value to replace?
My R302 looks healthy ie no sign of heat or burning but would it be wise to replace it anyway if I can get the same value resistor?
Regards,

[wasureppoi]

Re: LiteOn PA-6601-1A (600w) blows its TOP

Hi godonr, Q856 is on the underside of the board, it's a small SOT-23 surface mount transistor, my guess is that when the TOP blows, it can cause a surge of voltage to damage the Q856. Also in my case, the surge also damaged OPTO851. I couldn't get the exact repalcement, but it seems fairly standard in specification so I fitted one from my spare parts which had the same pinout.

So after replacing U801, Q856 and OPTO851, I have a fully working PSU.

Hope you have the same luck.

Cheers

Jon Fuge

Hi,
Forgive my ignorance. I have spent ten minutes examining under the board and still cannot find Q856 but gather it is a 3 legged chip. Would you be able to point me in the general direction? I have replaced my U801 and the TOP and can see the OPTO851 4 legged chip but what is that components name or value to replace?
My R302 looks healthy ie no sign of heat or burning but would it be wise to replace it anyway if I can get the same value resistor?
Regards,

[godonr]

Re: LiteOn PA-6601-1A (600w) blows its TOP

sounds good. this thread is full of hints on this troublesome supply. Some hits, some misses. the optos are another thing to check. good luck

[jhs]

Re: LiteOn PA-6601-1A (600w) blows its TOP

My 600W LitOn has gone.

I found F1, R302, Q301 and Q352 are dead. C852 will be changed before test.

Is there typically something i should also test? Q302, C301, C302 and C303 seems to be OK.

Thanks for help :-)

Hope to get it running or Apple/IBM gets out and MS/Intel gets in that beautifull case ;-)

[godonr]

Re: LiteOn PA-6601-1A (600w) blows its TOP

A while back Toasty posted a diagram to load the supply in series with a light bulb which helps protect the supply while testing. Might be worth looking for it on this BB. Best of luck!

[e5frog]

Re: LiteOn PA-6601-1A (600w) blows its TOP

Thanks for helping me sorting out this broken PSU. We got another G5 the same day but it would be nice to fix the current one to have as backup.

I have read through the thread and found these parts at DigiKey, seems that's what's needed:


I finally found a blown U801 (TOP249y) and went through the vacuum cleaner bag trying to find the missing piece with the text on it - but it had fallen on the floor...
Also the Q856 was missing half the capsule so I'll try and swap those two and the capacitor C852 and see if it starts up. Buying double of all recommended parts so I'll have spares if it blows again while fixing.
Haven't found any other problems following the advice in this thread.

[godonr]

Re: LiteOn PA-6601-1A (600w) blows its TOP

forgot to add... I don't have any single CPU units. That might be why I wasn't seeing this possibility.

[godonr]

Re: LiteOn PA-6601-1A (600w) blows its TOP

You must have the patience of Job!. I may try it just to see if I can do it... but as you said (and, I said in my post) the days of the G5 are numbered. We are back to PCs. I'm looking at getting rid of several hundred between the iMacs and towers. Only holding on to the intel boxes. It has always bugged me that I couldn't get the TOP repair totally worked out on this supply. Need any parts, let me know and appreciate all the input.

[Toasty]

Re: LiteOn PA-6601-1A (600w) blows its TOP

That being said, the value of these systems is dropping fast. Unless it's really loaded with the bells and whistles, you can't get much for them anymore. The only thing I'm doing is 1 dual CPU unit for me. The rest (4) are getting parted out.

Perhaps I will devise a wiring harness, as I have with others, to allow them to be run on the bench. I have all the connectors & parts.

Don't hold your breath though...

I did see a mod where a modern PC mobo and drives was fitted to one of these cases. A very nice job that looked nice inside with a proper mobo tray and all. Just have to find the link again...

Toast

[Toasty]

Re: LiteOn PA-6601-1A (600w) blows its TOP

Yes. The aluminum "tank".

All you're doing is keeping the board from any contact with the case.

Pick a single CPU unit. Remove the front and rear CPU fan assemblies. You probably have these out already.

Remove the 2 fans from one of these PSUs cases. The PSU won't run without them.

Form cardboard into a "U" shape with 2 inch "uprights" to fit into the bottom/PSU area. Make it longer than the PSU board. Plug PSU into mobo and position mains connection so you can feed the cord thru the normal connection hole. If necessary, use wire ties to secure the board from moving. Hook up the PSU fans, the rear CPU fans and slide the front CPU fan assembly back in.

You're not doing anything here other than testing the PSU. Stick a small piece of paper in the bottom rear slot where the air shield tab normally goes so the fans calm down.

On the bench these usually go click-click-fans for a second-off.

Toast

[godonr]

Re: LiteOn PA-6601-1A (600w) blows its TOP

Would love to see a pix of that. We are talking about a G5 tower, right?

[Toasty]

Re: LiteOn PA-6601-1A (600w) blows its TOP

nope

[godonr]

Re: LiteOn PA-6601-1A (600w) blows its TOP

Motherboard is OUT of the chassis, right?

[Toasty]

Re: LiteOn PA-6601-1A (600w) blows its TOP

Cardboard & a zip-tie

[godonr]

Re: LiteOn PA-6601-1A (600w) blows its TOP

Toasty.. given the way it sits underneath everything, what did you do? Make a special harness to hook up without place the p/s in the case?

[Toasty]

Re: LiteOn PA-6601-1A (600w) blows its TOP

Needs to be hooked to system.

[godonr]

Re: LiteOn PA-6601-1A (600w) blows its TOP

fixing to get rid of a bunch of these supplies... did think you could just jumper 13 & 14 (power on) to get readings. hate to throw in the towel on these supplies since there are still a bunch of G5s using and losing them. But, we are going cheap with HP Compaq 6200s and elite books. olivere sounds like you have a combination of the blown TOP and R302 failure. you did look there didn't you.

[Toasty]

Re: LiteOn PA-6601-1A (600w) blows its TOP

Checked the output FETs?