iMac iSight PITA.

[smason]

Wow, talk about difficult to work on.
Nice design Apple.

So I've managed to disassemble this thing, and I'm looking at a power supply problem. Even without a load, it just goes tick tick tick.

This thing looks difficult to service. The startup cap is visible, but really hard to get to.

One thing I know without even measuring, the big cap is getting voltage.
How do I know? I disconnected the supply, had let it sit for a while.
When I picked it up, I lit up. Wow. Been a while since I had a good zap.
This is the first SMPS I've seen that didn't discharge within a few seconds.

[Toasty]

Re: iMac iSight PITA.

Pics please. Never had the pleasure of seeing ones guts.

[smason]

Re: iMac iSight PITA.

Pics please. Never had the pleasure of seeing ones guts.

Will get some this evening

[smason]

Re: iMac iSight PITA.

OK here's some mediocre pics

[Toasty]

Re: iMac iSight PITA.

Celetronix! RUN AWAY! RUN AWAY!


Is there a standby voltage?

What are the output transistor numbers?

Measure across output on each rail to ground. If low or shorted, it's the same deal as the G5 Celetronix PSU, and you've found your problem.


Toast

[smason]

Re: iMac iSight PITA.

Yeah I had a shiver run up my spine whan I saw the label. Haven't done any measurement yet. Will get to it some time next wee, betweenk monitor repairs.

[Toasty]

Re: iMac iSight PITA.

@smason - *BUMP*

If you have a chance, could you look at this thread and give your input?:

https://www.badcaps.net/forum/showthread.php?p=153202

Toast

[alvaroba]

Re: iMac iSight PITA.

Hey guys, finally I found someone tath can helpme, I have an imac celetronix PSU tath randomly shut off, I need a good picture of the underside because it shows signs of broken and burning pathways and i want to rebuid them. If you can take a good picture and sendme or upload here I really thankyou.
Best regards
Alvaro
Sorry about my english, Im from Uruguay

[smason]

Re: iMac iSight PITA.

OK, time to finally take a close look at this Celetronix supply.
Initial disconnected tests, nothing shorted, outputs are all pretty high resistance to ground, and each other. Caps in-circuit test very low esr (probably in parallel) and capacitance is up around 1500uf.

Will apply AC and a load and measure outputs after dinner.

Not sure about the copper plate on the solder side, heatsink or rf shield? Either way seems to be glued on. Will need it off to test/replace the startup cap.

A few photos till I get some measurements:

[Toasty]

Re: iMac iSight PITA.

lol
Same outputs as the G5 PSU. PHD101NQ03LT

Please make sure the load is applied before power up. I think that's one of the causes of failures in the G5's after output replacements.

Toast

[smason]

Re: iMac iSight PITA.

Ok, wired a 1157 across the output, and connected power.
Ticking sound, no voltage on the grey wires (where load is connected) pulsing 12ish volts on the brown wire.
Guess it's time to peel that plate off and see what's under there that could be shorted.

[TheLaw]

Re: iMac iSight PITA.

Hmmph. If you want to be lazy, I think they sell these on eBay for cheap, but...

[TheLaw]

Re: iMac iSight PITA.

Sorry to interrupt this conversation but why does the iSight (camera I presume?) have it's own PSU board seperate from the main supply? And why does it have to be so beefy? Last time I checked Webcams could be run off a few mA @ 5V.

[alvaroba]

Re: iMac iSight PITA.

Smason youre the f**** master, Im trying to find the patway and the component burned on my power supply on every way trough google, and nothing. But your pics giveme what I need, y gonna try to repair the powersupply and let you if works (if not, I will play soccer with it). Beliveme I write much better in spanish

[smason]

Re: iMac iSight PITA.

Sorry to interrupt this conversation but why does the iSight (camera I presume?) have it's own PSU board seperate from the main supply? And why does it have to be so beefy? Last time I checked Webcams could be run off a few mA @ 5V.

The iSight is a model, it does have a webcam, but this is the main power supply we're talking about.

[smason]

Re: iMac iSight PITA.

Hmmph. If you want to be lazy, I think they sell these on eBay for cheap, but...

True, but I want to fix it, and I don't have high hopes that the iMac will actually work, so don't think it's worth spening money on.

[TheLaw]

Re: iMac iSight PITA.

The iSight is a model, it does have a webcam, but this is the main power supply we're talking about.

Oh...really? Maybe it's iMac w/ iSight. http://www.apple.com/support/isight/.

Regardless,

That's the whole PSU board. Make's sense now. I Was wondering why such a huge board with big components was dedicated to the webcam, of all things.

[smason]

Re: iMac iSight PITA.

Smason youre the f**** master, Im trying to find the patway and the component burned on my power supply on every way trough google, and nothing. But your pics giveme what I need, y gonna try to repair the powersupply and let you if works (if not, I will play soccer with it). Beliveme I write much better in spanish

Glad I could help. If you need any other info, just ask.

[smason]

Re: iMac iSight PITA.

For fun I put my semiconductor tester on the FETs. It said they were shorted D to S but I don't think so. Pulled 2 of them (man they're a bitch to desolder) and they test fine.

[TheLaw]

Re: iMac iSight PITA.

For fun I put my semiconductor tester on the FETs. It said they were shorted D to S but I don't think so. Pulled 2 of them (man they're a bitch to desolder) and they test fine.

I'd rather shoot myself in the foot than desolder a couple TO-220 or variants.