Jump to content


Photo

PowerMac G5 Quad PSU Repair?

G5 PSU Quad Repair

  • Please log in to reply
4 replies to this topic

#1 BadGoldEagle

BadGoldEagle
  • 68000

Posted 20 March 2017 - 09:53 AM

Hi folks.

Yesterday, I finished reassembling the PM G5. It is, as you probably know, a long and tedious process.

Plugged it to the outlet and immediately after that, 3 LEDs lit up: Processor A, Processor B and Trickle Power.

 

I thought the Processors weren't aligned properly but no. It seems the PSU isn't outputting anything on the processor side... I get 0 Volts at the power bus bar, and 0V at either CPU terminals. The logic board gets power though through the connector located near the plug. The other connector (towards the front of the unit) doesn't appear to be doing anything.

 

LED #3 "Power On" isn't on. (The air deflection sensor works: The Trickle power LED is off when the air deflector (aka plastic translucent door) is on and off when the door isn't there.)

So I definitely have a bad PSU.

 

So now, I have to tear it down again! Damn thing!

 

[Rant mode engaged] What were they doing? Why is it so complicated to remove the PSU? Why isn't there a door on the bottom of the Mac to take the PSU out? Grrr!!!

[Rant mode disengaged]

 

Rant aside, does anybody have an idea why it does not work?

I got this Mac for under $10 so I'd like to get a cheap fix. If not I'll probably have to get a replacement part (bit costly though!) What do you think of that reseller?

 

I did take it apart to clean it before even testing the PowerMac (I'm a dummie). So maybe there's something missing in there?

Will report back with pictures of the insides next Sunday.


COOL STUFF: Working original & nearly complete 1984 Macintosh w/ Picasso kit, still looking for a G440 mouse :p, NIB Newton MessagePad from 1993, iMac G3 400MHz DV Graphite

IN THE WORKS: The outstanding SE/30 (50MHz Powercache, Pivot Display Color Graphics) but also non-working 512K Hyperdrive w/ Manuals & Disks, Mac Portable M5126, SE Dual 800k, Classic II, HD40SC, Apple Djinn... I have a lot of restorations going on!


#2 BadGoldEagle

BadGoldEagle
  • 68000

Posted 20 March 2017 - 10:32 AM

Now that I think of it... I did lose a screw that was holding the PSU PCB. I'm starting to think that it might have been a conductive screw (like on the power bus bar?)


COOL STUFF: Working original & nearly complete 1984 Macintosh w/ Picasso kit, still looking for a G440 mouse :p, NIB Newton MessagePad from 1993, iMac G3 400MHz DV Graphite

IN THE WORKS: The outstanding SE/30 (50MHz Powercache, Pivot Display Color Graphics) but also non-working 512K Hyperdrive w/ Manuals & Disks, Mac Portable M5126, SE Dual 800k, Classic II, HD40SC, Apple Djinn... I have a lot of restorations going on!


#3 rsolberg

rsolberg
  • 6502
  • LocationVancouver Island, Canada

Posted 21 March 2017 - 01:04 AM

If you've done a major teardown and reassembly on the machine I wonder if there could be a loose connection to the front panel/power button PCB. The other thing that springs to mind is that almost any time I fully disassembled a G5, I had to do a CUDA/SMC (whatever name it went by at the time) reset with the button on the logic board for it to power on again.
68000: Mac SE Superdrive, 68040: Mac Colour Classic "Mystic" w/VGA mod

#4 BadGoldEagle

BadGoldEagle
  • 68000

Posted 21 March 2017 - 08:00 AM

The front panel board is ok. When I press the power button the fan spin up for a 1/8th of a second. PSU clicks as well.

I did reset the SMC. It did nothing.  :

 

Edit: Maybe I should remove the CMOS battery and then reset the SMC?


Edited by BadGoldEagle, 21 March 2017 - 08:01 AM.

COOL STUFF: Working original & nearly complete 1984 Macintosh w/ Picasso kit, still looking for a G440 mouse :p, NIB Newton MessagePad from 1993, iMac G3 400MHz DV Graphite

IN THE WORKS: The outstanding SE/30 (50MHz Powercache, Pivot Display Color Graphics) but also non-working 512K Hyperdrive w/ Manuals & Disks, Mac Portable M5126, SE Dual 800k, Classic II, HD40SC, Apple Djinn... I have a lot of restorations going on!


#5 BadGoldEagle

BadGoldEagle
  • 68000

Posted 27 March 2017 - 01:51 PM

Well, I just bought a replacement PSU for $60 shipped. It has already been cleaned and it's supposed to work. If it doesn't work I can return it and get my money back... we'll see.


COOL STUFF: Working original & nearly complete 1984 Macintosh w/ Picasso kit, still looking for a G440 mouse :p, NIB Newton MessagePad from 1993, iMac G3 400MHz DV Graphite

IN THE WORKS: The outstanding SE/30 (50MHz Powercache, Pivot Display Color Graphics) but also non-working 512K Hyperdrive w/ Manuals & Disks, Mac Portable M5126, SE Dual 800k, Classic II, HD40SC, Apple Djinn... I have a lot of restorations going on!






Also tagged with one or more of these keywords: G5, PSU, Quad, Repair

0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users