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Restoring an Apple Workgroup Server 95 (Photos included)

keehn

Member
Hey everyone. I'm sorta new here, but have been messing with macintoshes since 1990. One of the latest fascinations of mine have been to acquire and repair/restore vintage macintoshes. I've already done recaps on over a dozen logic boards, bringing back those macs to life (or as preventative maintenance).

This machine in particular was purchased on flea bay for a little more than I would have liked, but, given its rarity, I decided to take a chance. This machine was not only old and in questionable operation condition, but also RUSTY!! Here's some pictures of the journey thus far.

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A quick look inside shows the corrosion and rust of everything.

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Pretty much all metal surfaces show corrosion.

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The funny thing about this machine is that the logic board says it's a Quadra 950, yet the front facia is labeled "Workgroup Server 95".
I imagine that the R&D department was charged with making a server-quality macintosh. They all looked at each other and said "let's just use the Quadra 950."
Everyone agreed, but zero "F"s were given.

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The top deck that the hard drive, floppy drive, and DAT drive mounts to.

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Before I pulled the gargantuan power supply, I was fearing that the pooled corrosion was from a blown battery. I was VERY surprised to find that the previous owner had pulled the battery (luckily), but that the corrosion was coming from the PDS(?). And, on this board, there are ZERO electrolytic caps! Clearly Apple designed this board to last!


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In all my time working on computers, I have NEVER come across a CPU that had the pins separate from the die casing!


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The CPU pins I extracted from the slot.


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After an ultrasonic cleaning with a couple tide pods, the board came out looking near brand-new! I use my ultrasonic cleaner after I remove caps, but before I solder new tantalums back to the board. It works great to remove corrosion from the board.


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After cracking the mammoth power supply apart, even more rust presents!

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I'm mulling the idea of simply adapting a modern ATX to the case and not even bother with the existing PSU boards. I saw that another person had the same idea, the link is here: https://www.geekdot.com/fix-quadra-power-supply/

Anyways, this is all I have for now. I went ahead and ordered a used 68040 processor as I don't want to attempt repair on the existing CPU die.

If anyone has any tips for working on these machines, I'm all ears. But I wanted to share this, as I don't see much of anything regarding the Workgroup Server 95 online.

Keehn
 

ktkm

Well-known member
Nicely documented! I’ll be watching this thread!

Have you read about @BadGoldEagle ’s project?
 

joshc

Well-known member
I'm going through basically the same journey here:


I need to update that thread because a few things have happend since my last post, but my machine was battery damaged and also needed a PSU replacement which I'm still working on.
 

keehn

Member
The first order for a replacement 68040RC33M CPU fell through. Apparently the seller's QA didn't pass the chip, so they canceled and refunded. I sourced another one from China, so this is going to take some time (the other seller was US-based)....

I also ordered a couple gallons of rust remover solution, which arrives Tuesday. I've had good luck with the solution in the past, so I'm expecting positive results here as well. I'm also going to retrobrite the case plastics, but that's a low-priority repair at this moment.

@ktkm, I'll have to check that link out. Thank you for sharing :)

Keehn
 

keehn

Member
It's been a minute, but family, holidays and life in general took priority over my WGS 95 project.

I went ahead on converting a standard PC ATX power supply over to support the logic board and, while it works, it is HIDEOUS!
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To that end, I chose to bite the bullet and ordered a Quadra 900 PS off eBay. It should be here by next week. I guess I agree with Steve Jobs: The computer should look good on the outside AND inside!

Side note: Yes, I am building the EagleMoss USS Enterprise D model. That's the binder they give you to store your monthly assembly instruction magazines in.

I did use the PS to power on the board (using the speaker for audio confirmation) but no joy. The LED lit up and the speaker clicked once, and that was it.

This board has no electrolytic capacitors, but that doesn't mean tantalum/solid-state caps don't go bad, so I went ahead and unsoldered one end of each cap so I could do a Fluke multimeter test. To my surprise, quite a few of them tested bad, with one 47uf cap going as high as 60uf! If you look carefully, I put a small white dab on each of the bad caps for identification.
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I was also able to source a good 68040RC33M CPU and tested it in my Mystic Color Classic during troubleshooting. There are two standard 3-lead transistor packages on the board, one being a 7805CT and the other a LM317. The 7805CT is a linear voltage regulator and the LM317 is a variable voltage regulator. I don't have equipment handy to test either one, so I'll just buy new ones simply to eliminate those from the equation.

Towards the bottom-right of the photo is a TDA7056 3W BTL Mono audio output amplifier (looks like a bunch of MOSFETS in a single package). I'm not going to worry about this, as it shouldn't have anything to do with general board operation. If it were bad, then the audio output wouldn't work. To that end, I hooked up a monitor during my second power-on test to remove the audio circuit from my diagnostics, and still, no joy, no video output appeared.

Thus, I put an order into Mouser Electronics for the desired components and am, again, playing the waiting game.

Keehn
 

Franklinstein

Well-known member
I didn't see any pictures of it, so did it come with the Workgroup Server PDS Card? Should've been a big card that slots into the slim black PDS and provides fast SCSI and a L2 cache. Without that you've basically just got a regular Quadra 950; the PDS card is what made it a "real" WGS 95.
 

keehn

Member
I didn't see any pictures of it, so did it come with the Workgroup Server PDS Card? Should've been a big card that slots into the slim black PDS and provides fast SCSI and a L2 cache. Without that you've basically just got a regular Quadra 950; the PDS card is what made it a "real" WGS 95.
Interesting.... My WGS didn't come with this card. I did a quick Google and saw the card in question. I'll have to keep my eyes out for anyone who has one for sale.
 

Unknown_K

Well-known member
The cards are very rare, only the wgs95 came with one and most people used the regular 950 as a server.
 

MacKilRoy

Well-known member
It’s probably worth saving the images for these somewhere, so here are pics of one that sold on eBay recently.

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keehn

Member
...Whelp! It looks like I need to put up some eBay search alerts :)

Also update: I got the Mouser components and replaced everything on the board, but still, no joy. I have the board sitting outside in the cold. In a little while, I'm going to bring it back in and run my FLIR-like camera on it to observe the hot spots.

What's a bit annoying about this project is there are no slam-dunk indicators (e.g. visibly burnt capacitor) telling me where to search. Plus, I don't have any schematics of this board, so there's a lot of tedious multimeter probe readings, AND...the board is multi-layer, thus the power connector traces aren't visible.

This board WILL live again, even if I have to replace every. single. component! LOL
 

slomacuser

Well-known member
Well I know for at least 3 WGS95 computers that didn’t had that card installed. Could be that Apple didn’t use that card on all WGS95 systems …
 
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