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Old 12-13-2017, 10:10 PM   #141
Kansas Sparks
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Default Re: Suspect Bad PS Apple AcBel API 1PC36

CORRECTION: C7 Capacitor noted on the above MAP.jpg shows incorrect info. Should read : C7 - 220 µF /35V
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Old 12-13-2017, 10:48 PM   #142
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Talking Re: Suspect Bad PS Apple AcBel API 1PC36

While you're at it, would you change the Yellow dots to something that contrasts better? Orange, purple, polka-dot...
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Old 12-15-2017, 01:20 PM   #143
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Default Re: Suspect Bad PS Apple AcBel API 1PC36

Purple it is.
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File Type: jpg MapB.jpg (495.4 KB, 36 views)
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Old 12-15-2017, 03:24 PM   #144
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Old 09-02-2020, 08:50 PM   #145
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Default Re: Suspect Bad PS Apple AcBel API 1PC36

Thanks to folks on this forum (Toasty especially) for everything on this and related threads which enabled me to repair the ACI1PC32 unit in my G4 MDD. This is my experience for the record…

Initial symptoms: power light flashed but no boot. On removing the PSU, I measured good standby voltages but no 3.3/5/12 on grounding power-on. The fans twitched but that was all. I pulled the guts out and could measure good B+ (370v). There was no evidence of bulging caps or other distress.

First, I replaced 10 of the 12 shotgun caps using this fine list (https://www.badcaps.net/forum/showpo...&postcount=112) from Digikey. I was able test and eliminate C7 in circuit and C8 by removal. None of the others was bad but a couple were leaky. I used this excellent ESR meter: https://www.digikey.com/product-deta...004-ND/9687220 Sadly, this didn’t do the trick, so I ordered the 7 of the 10 “other” caps (the big guys C5/C4/C37 tested healthy in-circuit and certainly seemed to work well).

From various discussions, it seemed like C45, C32 and C30 might be the next suspects. So I pulled and tested those. C45 and C32 had a high ESR but they weren't completely fried .. and C30 was too small to check. I replaced these, retested and .. praise be! .. all outputs fired up. So I applied new silicone caulk, partially re-assembled and re-tested. Nothing. Back to standby only. Rats.

At this point, I could only guess that other caps were marginal. So I pulled C53/C55/C56/C57. I could only test the 4.7uF guys and they both checked good. But replacing all of them indeed got it working properly. So I can only conclude that one or both of the small 0.47uF caps were the culprit.

Note that the best way to deal with the original adhesive caulk for me was to cut between caps with a modeling knife so that each cap could be easily desoldered individually.

Also: after a test, to safely discharge and measure the high voltage on the primary caps, I’d hook a multimeter between B+ and R4, the PFC current sensing resistor, and used a 10K+ resistor to bleed between meter terminals. Otherwise, it would take at least 20 minutes to discharge adequately. This was after It’d been tickled once!
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Old 09-27-2020, 06:46 AM   #146
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Default Re: Suspect Bad PS Apple AcBel API 1PC36

Hi there. I have a Power Mac G4 with an Acbel APi1PC36 PSU. The fault symptoms sound similar to those reported here - pressing the power on button produces a twitch on the fans and a red LED (D518) on the motherboard flashes once then nothing else happens. I have removed the PSU and, using a 22R resistor to bridge pin 6 (3.3v sense) to ground and a jumper between pin 11 (green) and ground, it starts and runs delivering the expected voltages at the other pins. I have since replaced the following caps: C8, C7, C10, C16, C13, C21, C29, C59, C60, C35, C41, C57. I have an analog Ohm meter to test leakage and all of the removals seem to charge up and hold charge as expected. Only C60 was slightly domed at the top but still seemed to be OK. Obviously, I have left all of the new replacements in and the PSU still works on the bench, but not when connected to the Mac. Is there any point in my replacing any more caps, or should I be looking for a motherboard fault, in which case some help and advice is sorely needed!
P.S. I have just attempted another re-start and the Mac powered up with a start-up tone, ran for maybe 5 seconds, then powered off.
P.P.S. It now seems to keep running...... Advice please - change the rest of the electrolytics or no?

Last edited by useanavo; 09-27-2020 at 07:21 AM..
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Old 10-23-2020, 05:54 PM   #147
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Default Re: Suspect Bad PS Apple AcBel API 1PC36

I'd replace all "shotgun" and "other" caps before looking elsewhere.
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Old 11-19-2020, 11:08 PM   #148
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Default Re: Suspect Bad PS Apple AcBel API 1PC36

This is someone from the future... *ahem* Many thanks to all of you in this discussion.

I managed to fix my AcBel by replacing the bulging big ones (2x2200uF, 1x1000uF) and the small ones (C30 C32 C45, but not sure which one was the cause). Before it was fixed. it was turning on and off instantly and standing by with 25V and 5V.

I did notice that even they went to town with the glue, some parts managed to lift the traces and became loose. I had to put more solder on them so they could bridge to something next to them to stay in place.
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Old 11-21-2020, 11:45 AM   #149
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Default Re: Suspect Bad PS Apple AcBel API 1PC36

Lifting board traces is either to much heat or staying one the trace to long with to much heat
or not enough heat and you are having to stay to long on the trace

One solution is add fresh solder to the joint with the right amount of heat

To determine if you are using enough heat is to the iron on the joint and as long it is not a double sided board with large ground planes you should be able to melt the the soldering joint in less than 3 second if not increase the heat setting

Now with my soldering station I set it for 675*F but I get on a soldering joint and once the parts pin is loose either suck the solder off the joint or move the pin out of the hole

Now I also have a Desoldering Station I set it for 775*F so it quick to melt the solder and suck it out of the joint hole then take the tip off the board as soon as possible to keep from burning the board now on double sided board or ground planes you have to leave it a little bit longer for the solder to melt

I hope this helps you
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9 PC LCD Monitor
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30 Desk Top Switching Power Supply
10 Battery Charger Switching Power Supply for Power Tool
6 18v Lithium Battery Power Boards for Tool Battery Packs
1 XBox 360 Switching Power Supply and M Board
25 Servo Drives 220/460 3 Phase
6 De-soldering Station Switching Power Supply 1 Power Supply
1 Dell Mother Board
15 Computer Power Supply
1 HP Printer Supply & Control Board * lighting finished it *


These two repairs where found with a ESR meter...> Temp at 50*F then at 90*F the ESR reading more than 10%

1 Over Head Crane Current Sensing Board ( VFD Failure Five Years Later )
2 Hem Saw Computer Stack Board

All of these had CAPs POOF
All of the mosfet that are taken out by bad caps

Last edited by sam_sam_sam; 11-21-2020 at 11:48 AM..
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Old 11-21-2020, 01:40 PM   #150
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Default Re: Suspect Bad PS Apple AcBel API 1PC36

Thanks for all the soldering tips. I know how to solder pretty well. What I meant was the parts started lifting traces from the board on their own from the other side. That surprised me since they went nuts with the white stuff, everywhere, all over.
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Old 11-21-2020, 03:40 PM   #151
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Default Re: Suspect Bad PS Apple AcBel API 1PC36

What a crap-e board
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