Imac late 2006 psu 614-0380

[Sylvester]

Imac 17" late 2006 cd MA710xx/A, psu 614-0380.

Mac won't power up, nothing, as some of you will know its not easy to strip down, anyway,got to the psu,no obvious signs of bulging although the 120uF 450v had some goo on one leg, I'm not sure of the value of the other 3 caps.

What is the best way to test this psu, I'm not sure if the logic board has leds on it, bearing in mind the front of the case comes off unlike the earlier ones that the rear came off?

[cheapie]

Re: Imac late 2006 psu 614-0380

I don't know if those are ATX PSUs or not... If they are, the best way to test is by shorting PS_ON to ground and checking all of the voltages.

[PeteS in CA]

Re: Imac late 2006 psu 614-0380

Desktop Mac P/Ss ca. 2002 were basically ATX, with the -5v pin of the 20-pin connector being +3.3V instead. Also, the O/P harness was much longer.

[Sylvester]

Re: Imac late 2006 psu 614-0380

Apple can be confusing, its not the desktop but the flat panel all in one mac, the output side has a 5 pin plug,

AcBel AP150T61 psu 614-0380

[Toasty]

Re: Imac late 2006 psu 614-0380

Hook it up to power and see if you're getting 12vdc. If not, try a small load across it such as an automotive marker lamp. These react when a load is presented, but should at least be giving you 12v when measured. (Voltage may "wobble" a bit because of no load.)

T

BTW - show a pic of the "goo" on the mains cap. Also, aren't there 5 caps plus the mains one?

EDIT: FYI - It's API5OT61 - api5ot61

.

[Sylvester]

Re: Imac late 2006 psu 614-0380

The goo was on the leg that was insulated as it went into the cap, I did think it resembled flux but there's no reason for it to be there, no obvious signs of swelling, prob better to check for 12v but not sure how to check on this one.

Got me on that typo!

[Toasty]

Re: Imac late 2006 psu 614-0380

Stick the probes in the connector until you get a reading...

Black should be ground(-)

Still no pics to go by....

T

[Sylvester]

Re: Imac late 2006 psu 614-0380

Used a 12v test lamp on the leads, nothing, using a meter on the leads basically nothing .02v.

There are only 3 caps 1 is 1000uF 16v, I can't read the other 2 ( they appear ok), 1 small cap at the side 68uF 25v, and the mains cap 420v 120uF.

[Toasty]

Re: Imac late 2006 psu 614-0380

I'd say the mains cap is bad. It appears to be electrolyte leakage at that leg.

Check voltage input at bridge rectifier - AC
Check voltage output at bridge rectifier - DC
Check voltage across mains cap - DC
Report findings please.

Check fuse(s) - brown square device at mains input area.

Thanks for the pics!

T

[Sylvester]

Re: Imac late 2006 psu 614-0380

Sorry for the delay in posting voltages but there seems to be differing voltages between meters.

Fuse is ok.

Bridge ac 230v
Bridge dc 335v on dmm and 600v on analog meter
Mains cap dc 335v on dmm and 600v on analog meter

do they make sense?

[Toasty]

Re: Imac late 2006 psu 614-0380

Sounds like the analog has a problem.

230v x 1.414 = 325v which is close enough as your AC reading or DC reading is probably off a bit either way. The voltage across the cap would be correct until the unit was actually under load, at which time I would be looking for upwards of 390v. PFC boost voltage.

Where are you located? Would you update your profile? From the 230v, I'm guessing it's not the US.

My next step would be to replace the small cap. The mains cap "leakage" has me concerned, but without the ability to test it, leave it for now. The fuse intact and no obvious burned components would also lead me to believe the boost section is okay.

T

[Sylvester]

Re: Imac late 2006 psu 614-0380

Updated profile, replace the 68uF 25v?

[Toasty]

Re: Imac late 2006 psu 614-0380

Yes.

[Sylvester]

Re: Imac late 2006 psu 614-0380

May have one, failing that, tuesday.

Maybe even a new dmm

[Toasty]

Re: Imac late 2006 psu 614-0380

Something close? Higher voltage is okay @ 47/56/82/100 uF.

Two lower voltage in series (capacitance divides) - e.g., (2) 100uF @ 16v in series = 50uF@32v.

T

[Sylvester]

Re: Imac late 2006 psu 614-0380

68uF 25v cap replaced

[Toasty]

Re: Imac late 2006 psu 614-0380

And...?

[Sylvester]

Re: Imac late 2006 psu 614-0380

Plugged it back into mobo but nothing, I'll try it with the test lamp and see if there's any change

[Sylvester]

Re: Imac late 2006 psu 614-0380

No change from the original, bridge dc is 325v, 335v was probably a mistake on my part with the reading

[Toasty]

Re: Imac late 2006 psu 614-0380

Okay. Hmmm...?

Try removing that shield from the foil side as it hides 50% of the components. Another pic like #14 above with good lighting & no glare, please. Nice and sharp.

Start looking for torched resistors or transistors.

What are the 2 components mounted to the heatsink next to (1) the mains cap, and (2) on the other side under the lip next to the 2 blue caps? Report markings please.


Inspect and verify the value of the large (2 watt?) green resistor next to the mains cap.

T