iMac 20" G5 AcBel PSU Question

[wonka1964]

Hi

I have a 20inch iMac G5, no iSite but it has an AcBel 180W psu with ambient light sensor. I was recapping the board and the solder iron accidentally touched a few surface mount resistors that now have fallen off (small 0402 size resistors). The Apple serial number on the PSU case is 614-0366, Rev B and the serial number on the pcb is AcBel AP14PC46-280 03L66-001 Rev A, and my question is: Since it seems impossible to find a schematic for this PSU, does anyone have this unit in hand and could you please read the component values for reference designators R101, R85 and R108? You will need magnification to read the number markings on these small packages.

Thanks and much appreciated,

Steve

[Toasty]

Re: iMac 20" G5 AcBel PSU Question

I do not have a 614-0366, but a 614-0326. The items are near the +5vsb / purple wire correct?

R101 - marked 103
R85 - marked 62b
R108 - marked 11b

Hope this helps!

Toast

[wonka1964]

Re: iMac 20" G5 AcBel PSU Question

Toasty,

Thanks. I have never seen that resistor code before. I believe that even the three digit EIA-96 marking method uses capital letters as multipliers but these resistors seem to have small letters. If you have time, could I ask you to measure the value for each one of the three resistors. Measured out of circuit would be best but if you do not want to remove the resistors, measuring in circuit will be ok.

Thanks,

Steve

[Toasty]

Re: iMac 20" G5 AcBel PSU Question

Measured in circuit:

R101 - marked 103 - 7.16kΩ -> by code = 10kΩ
R85 - marked 62b - 3.66kΩ -> by code = 4.32kΩ
R108 - marked 11b - 1.16kΩ -> by code = 1.27kΩ

Since all of the measurements are less than the code markings, I believe that the markings are correct by EIA-96, uppercase/lowercase letters not withstanding. It seems to make sense to mark a component with a lowercase "B" so as not be confused with the number "8". A lowercase "b" could be confused with the number "6", until you start to look around and notice other component markings that the 6 is definitely different.

If you notice in the picture, the 2 resistors to the left both use an uppercase "C", (36C & 40C) which can't be confused with any number.

Here's a handy tool if looking up charts is difficult or a pain:
http://www.hobby-hour.com/electronics/smdcalc.php

Another item of note - The Ambient Light Sensor is not, in any way, a part of the PSU. It can be removed from the PSU without opening the unit and placed on another "plain" PSU. Many folks seem to think that they have to get a PSU with the ALS, and they don't. Just unplug it and undo the clips holding it to the PSU grille.

Cheers!
Toast

[alvaroba]

Re: iMac 20" G5 AcBel PSU Question

Im searchin for the schematics for this psu: Acbel p/n 614-0366 (iMac G5 20")
At least I need a god picture of the underside, where I can read the components values since some of them burned out.
I hope wonka1964 have some pics or someone else have take pics of similar psu. And also if someone have the circuit diagram Ireally thanks him.
I know my english sucks , but I think theres is no other Uruguayan citizen in this forum then forgime me
Thanks
Alvaro

[Toasty]

Re: iMac 20" G5 AcBel PSU Question

There are no schematics for this or any other PSU unless someone took the time to tear one apart and draw it. Schematics are proprietary to the manufacturer and not made public. These are not -intended- to be repaired, but rather replaced for safety's sake.

If your unit is dead, then perhaps obtain another. The replacement does -not- have to be the same number, just -for- the same unit. In other words, all 17" iMac G5 PSU's fit all other iMac G5 17" systems and same goes for the 20" systems. ALS is _NOT_ part of the PSU, but rather a snap-on device that can be transferred.

There is a seller on U.S. eBay with 2 of these identical models available for $63 and $25 shipping to your country. However, that's a "Buy-It-Now" price and he also has "Make an Offer" of which there are currently 3 for the 2 PSU's he has. They are used, but these may help you if you're in a bind. I have dealt with this seller before with no problems.

http://cgi.ebay.com/ws/eBayISAPI.dll...m=380342367556

If -you- can post pictures of the damage, perhaps we can get you close enough in parts to get yours fixed.

Toast