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Guide : SFX PSU Conversion for Quadra 630/Performa 6200

demik

Well-known member
Hello,

Introduction :

This is a quick guide on how I upgraded the PSU on my Performa 6200. This guide applies to all macs which share the same case (Quadra/LC/Performa 630, Performa/PowerMac 62XX/63XX)

PowerSupplys inside this case are an afterthought. They are badly designed and the first cause of dead of Quadra 630 / Performa 6200 and friends. The case cooling doesn't help, but this PSU model is especially bad. About 80% of causes on this models are a blown PSU. You can't even put any PSU that fits, because the PSU is also used as a guide for the logic board.

If it makes this sound : View attachment sound.m4a, It's about to blow up, mine died a few minutes after this (with a spectacular bang, as expected)

The caps evaporated/overheated into the case, which can result in stuff like this :

PSU_1.jpeg.f73d841338273905a2cf190ea11ec307.jpeg


There is also overheating marks around some parts :

PSU_4.jpeg.6f54f6093c02788bf47b25b7596b94b4.jpeg


Note : the diagram pictures comes from the following thread, thanks to @Floofies for his work.





Hardware needed

- 74HC04 in DIP Format

- DIP14 socket

- 10kΩ resistor

- 7kΩ resistor

- Heat shrink tubbing

- SFX Power Supply (NOT SFX-L those won't fit, just standard SFX)

Tools needed

- Set of screwdrivers

- Drill

- Metal Saw

The PSU I choose for this project was the Enermax Revolution SFX 550W (ERV550SWT) for the following reasons:

- It's decent quality enough, don't want to kill a collectible Mac with a cheap PSU

- It's passive until 165W (usefully in this case)

- I had it lying around

- It has a multitude of protections most of which the original PSU doesn't have :

  • short circuit protection
  • over voltage protection
  • under voltage protection (brownout)
  • over current protection
  • over temperature protection (yep !)
  • over power protection
  • surges and inrush current protection.



revolution_sfx.jpg.3c3e2bdaeb747cc945354546ed35d5ce.jpg


You can choose any SFX PSU you like, but I recommend at least over temperature protection in this case, and it has to provide at least :

- 80mA on +5VFSB (Standby Power)

- 8A on +5V

- 3A on +12V

- 200mA on -12V

Process :

First you need to open the patient, remove the Logic Board and unplug the following wires from the PSU :

PSU_2.jpeg.68fe146719ed109a00c0adc2e8d7aaff.jpeg


- Fan power (two wires, red and black)

- 6 Pins small grey cable near the Fan connector (used to boot the system + power the keyboard)

- PSU Connector (the big square one with blue/black/red wires)

Now you can usually remove the old PSU. Here it is against the SFX PSU

PSU_5.jpeg.42897297017624a62388e1a033f9c225.jpeg


You need three components from the old PSU :

PSU_6.jpeg.316bcb6b1a7f24025c21fefa77dc6a82.jpeg


- Logic board connector

- Fan connector

- Power Loom (cut as close as possible from the old PCB)

- Power Socket (same, cute as close as possible)

Remove the new PSU from its case :

PSU_7.jpeg.18e2005b6dbf9761608d2004ab47aa5b.jpeg


Cut the bottom of the case to it can fit inside the old PSU. You only need the plate on which the PCB is fixed. Secure it into the old PSU case. You need to drill a hole to reuse one or more of the old screws and use the rail which was previously used by the old PCB.

PSU_8.jpeg.aa14a3ae2ac90d2dfeaf9d4062a83cc8.jpeg


If your PSU has a power distribution board (like mine), remove it (cut the wires as close as possible from the PCB). I wanted to use it first, but it's really difficult inside this case.

Now the straightforward (and time consuming part):

- Weld the old power loom to the new PSU

- Remove unused power wires from the new PSU

- Weld the old power socket to the new PSU

The tricky part:

Build a boot signal concerter to convert the Mac Power Signal to the ATX one

pinout.gif.b1ec315fc12207308c8ad635f5b4c2d5.gif


You can use a PCB or make it redneck style. Please insulate the components with everything you can : electric tape, glue, heat shrink tubing, concrete, whatever.

I admit not being proud of this part

PSU_9.jpeg.41f4562f87e9b482dc99eb74afea6d40.jpeg


Secure everything and put back the old PSU cover plate :

PSU_10.jpeg.c78647582406daae1c31769e74253aa7.jpeg


Back in the case

PSU_11.jpeg.a5ce635291ff3cb55d5b4f67bae31c8c.jpeg


And voilà ! Booted first try :)  

Hope this will be useful for somebody. Took me 4-5 hours to to the whole thing

Good hacking !

 
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Floofies

Maker of Logos
Spectacular work on this conversion! That's a real top-notch job you did, stuffing it into the original case. Also, soldering right onto a DIP socket is so cheesy but I like it anyways, and I wish I'd thought of it!  :p  I'm really happy that my earlier work is useful for other Quadra 630-series owners!!! I am actually surprised it booted on the first try, too; I had to build 3 different prototypes of that "boot signal converter" before I could get it to be stable, so I wasn't sure if the resistors in my diagram were going to work for everyone.

 

Byrd

Well-known member
Funnily enough, I just came online looking for Quadra 630 PSU issues and here is your thread from this week!  Thanks so much @demik for the instructions, they are great.

I hadn't fired up my LC630 for six months, and was met with a similar squealing sound when I attempted to power it up.  Once it fired up and chimed for ten seconds, but now no more - squealing galore.  Is it worth recapping the '630 PSU in your opinion or should I just bite the bullet and perform this modification.  I presume Astec PSUs probably shouldn't be given too much love.

JB

 
Last edited by a moderator:

demik

Well-known member
Spectacular work on this conversion! That's a real top-notch job you did, stuffing it into the original case. Also, soldering right onto a DIP socket is so cheesy but I like it anyways, and I wish I'd thought of it!  :p  I'm really happy that my earlier work is useful for other Quadra 630-series owners!!! I am actually surprised it booted on the first try, too; I had to build 3 different prototypes of that "boot signal converter" before I could get it to be stable, so I wasn't sure if the resistors in my diagram were going to work for everyone.
Well thank you ! The DIP socket is cheesy but I didn't want to weld the wires again in case something went bad.

Funny enough, I didn't have a 7kΩ resistor around and used two 10kΩ, if that helps. Thanks again for your job, saved me a ton of time. I will use your work on my 6400 to ATX conversion to get its soft power working.

Funnily enough, I just came online looking for Quadra 630 PSU issues and here is your thread from this week!  Thanks so much @demik for the instructions, they are great.

I hadn't fired up my LC630 for six months, and was met with a similar squealing sound when I attempted to power it up.  Once it fired up and chimed for ten seconds, but now no more - squealing galore.  Is it worth recapping the '630 PSU in your opinion or should I just bite the bullet and perform this modification.  I presume Astec PSUs probably shouldn't be given too much love.

JB
Thanks again. This isn't my first conversion (did a Quicksilver and PowerMac 6400 to ATX before). Having a tendency to butcher things, this is one of my cleanest conversions. The good old axle grinder was too much involved in previous conversions  :/  

Regarding your PSU, I wouldn't bother with it. Caps on this PSU are one thing, but they are diodes, resistors and maybe some IC that are undersized. A new PSU will have more efficiency, which result in less heat inside the case. (And a somewhat lesser electricicty bill) Astec did some good PSUs but this model is none of them.

I will happily help you if you do a similar SFX based conversion.

 

demik

Well-known member
Ha yes, sure, here they are. Same order as the original post.

Evaporated caps:

PSU_1.jpeg


Overheating marks:

PSU_4.jpeg


Old PSU (remove wires) from top:

PSU_2.jpeg


Old PSU and donor PSU:

PSU_5.jpeg


Connectors to harvest:

PSU_6.jpeg


New PSU opened:

PSU_7.jpeg


Cur new PSU plate into old PSU:

PSU_8.jpeg


Pinout for Power Circuit:

pinout.gif


Not that proud part:

PSU_9.jpeg


Everything secures:

PSU_10.jpeg


Back into the case:

PSU_11.jpeg
 
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