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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

 
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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
 

Rhysco

New member
Hi,
Do you know if I can buy one of these in Australia already to go?
I have an LC 630 DOS compatible that I really want to be able to use. I'm confused as to whether there is value in recapping the existing power supply given what I have read about it being prone to failure and operating on the limit.
 

Byrd

Well-known member
Hi also from Austeralia :). The adapters no aren't around - I'd give some time to the existing LC630 PSU, unless particularly fried. Mine resurrected itself but I know soon I'll need to crack the case and recap it.
 

Rhysco

New member
Mine almost looks burnt in the middle in the same area in one of the photos. I’m amazed it still works intermittently. The section of the lid over the power supply is also looking burnt. I love old macs but proprietary parts suck!
 

Trash80toHP_Mini

NIGHT STALKER
Not at all convinced the PSU bing worst component of that design, as mentioned the cooling system is inadequate/downright counterproductive. The first thing to do when acquiring any of these very cool cases would be removing the side panels ant removing the dust filters. I do not mean they have actual dust filters!

The offset cooling slots of case/chassis setup does the filtering all on its own. Collecting ludicrous amounts of dust in order to impede airflow for cooling would be an elegant solution were dust collection the goal, however the result is insanely counterproductive. Cannot imagine that feature and impeded airflow not being the root cause of overheating induced PSU failure in these machines.

IOW, I'd be hesitant to nick Astec's design for PSU failure in this particular case . . .
. . . system packaging design disaster . . . again Apple. :rolleyes:


edit: unintentional puns left intact
 
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pizzigri

Well-known member
Hi everyone, I have rebuilt the 6200 PSU with a SFX supply to be able to power a 6500 board. I had at one time not one but THREE 6500, one in pristine condition (which I sold) and the other two in disarray (got for 200 Euro from a local school). The cases are shot; one had a burned PSU. All lack hard drives. In any case, I got a couple 6200 from the same source (...another 100 Euro) in excellent condition, but again, both burned PSU.
So I had an idea to build a 6390... which doesn't exist :) ...
by placing the 6500 board in the 6200 case. First hurdle, find and adapt a SFX psu.
Done, and rewire the connector to add 3.3V from the psu.
No prob. Then, build the soft power adapter, as per instructions. Done.
So I assemble the whole thing, and power it up. Everything works!
Wow, fantastic. well not really, I hadn't noticed but, no "bong" though- actually, no sound at all.
Go back, and check everything, I realize I used the much simpler monitor out board of the 6200 rather than the much more complex double decker board of the 6500, which goes into the subwoofer and not the usual tinny loudspeaker used by most of these Macs.
OK, replace the simpler board with the 6500 one, connect it to the subwoofer, just 'cause, maybe, once all works, I can add an external pinjack connector to feed the now external subwoofer.
Nada, no sound, only some sort of growling at start.
If I connect a pair of headphones on the front jack, the sound is crystal clear, so it is simply not working with the original double decker video/audio out board.
Curiously, no sound is also coming out from the rear pinjack connector on the M/B.
On a hunch, I remove the 6500 board from the 6200 case, and lay the whole computer on cardboard boxes, using the original harness and power supply of the 6500 (which I kept in my parts bin).
Let there be sound, and There was sound! So, it MUST be the harness. I checked every cable and I realized that it's not the harness, per say.
It's actually the PSU: the IDC10 (of which only 6 are wired) connector for the soft power on that comes out of the PSU has all its six poles connected, while the 6200 only has four: 1,2,3 and 5.
I imagine that poles 4 and 6 are used... I dunno, for powering an on-board amp for the subwoofer? But, there's the same LM4861M, 1W class D amp on both monitor out boards, so I have no idea what's it for.

Does anyone have a pinout of the IDC10 connector of their 6500 that I can use to restore audio to my FrankenMAC?
 

pizzigri

Well-known member
So I fired up the 6500 board after I identified the two “nc” pins 4 and 6 on the IDC connects of the 6500 psu. I find 3.3v across these, with neg being pin 4. Power is fed only once the PSU is turned on by soft power

What I cannot figure out, at least without totally disassembling the PSU, would this 3.3V be connected to the sense pad (brown wire in ATX) in the modern SFX PSU I used? It does not seem to come from the "main" hi power 3.3V rail. And the Neg line also does not seem to be connected to the common ground. I'm a bit puzzled, can anyone help me out?
 

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pizzigri

Well-known member
OK... so i disassembled the whole 6500 original PSU again, and could not trace the 3.3V easily, however, my observations concluded that, yes, pin 4 is gnd, and is connected to common gnd, and pin 6 is in fact a standard 3.3v rail, that turns on as the machine is turned on (so no, I could not use the 3.3VSB line I have inside the SFX board).
for some reason a 6500 board needs 3.3V to enable sound again; I reworked the SFX PSU mod and connected pin 4 to the GND already coming on the perf board on which I built the soft power on circuit, and connected a wire coming from the standard 3.3V output of the SFX board.
Fired up the machine, and bam! got Audio. With the original 6200 harness, and reworked PSU.
So, whoever wants to use the info provided by the OP to power a 6500 board inside a 6200 case, this is a necessary addenda.

Now it begs the question; would the 6360 have a different PSU? yes, because it has a PCI connector inside. However, it would be nice to know if that PSU has pins 4 and 6 connected to 3.3v as well.
 

demik

Well-known member
IIRC the 6360 has a different PSU for the 3.3V. Can't remember where the 3.3V is coming from, but it goes through the harness. One of the ground is connected to 3.3V in a 6400/6500 case.

Check the wiring diagram over here: https://powercc.org/takky/

Edit: didn't see that you got it to work at first. Good job on that !
 
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