Refreshing a Quadra 605

Nycturne

New Tinkerer
Dec 18, 2024
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I lucked out and found a Quadra 605 in surprisingly good shape at a local PC recycler. The case has only minimal yellowing, and the plastics are in better shape than I was hoping for. Only visible damage is a bit of an indent in the top case from where someone probably scraped a monitor across the top. I‘ve been wanting an 040 machine that isn’t a laptop, and if I can grab an Apple IIe card, this will be a rather nice project. Both the floppy drive and sound work, and it still boots from the original SCSI drive.

Opening up the case, the logic board is in good shape. No obvious evidence of corrosion or leaky caps. The battery didn’t leak either. Good starting point, but I’ll want to swap the caps before they do damage to this board. So let’s get the board out and get started:

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Well, here’s the bad news. In the process of removing the caps, I managed to lift *3* solder pads. Both pads for C149 and the positive lead for C105. From the schematic, C105 is a filter cap for the SCSI power port as I suspected from the placement. Continuity testing the 5V line for the power port, it looks like the second filter cap is still connected properly. So I can bodge a wire to either the 5V pin on the port (easier), or the second capacitor (harder). But since I’m going with a BlueSCSI, I can probably get away with not repairing this immediately as I don’t need the 4-pin power connection, but I’d like to fix this while I am setup to do the work.

C149 I need to fix to keep sound working, but since it just needs to be connected to C150 and the correct pin on the sound chip, this should be a pretty simple repair. In terms of damage, it could have been much worse. Unfortunately, I don’t have any hookup wire fine enough to attach to the sound chip pin at the moment. So I’ll need to grab some to finish this work.

Sadly, the board won’t be quite as nice as how I got it, but I’m thankful the bodges will be straight-forward. While I’ve done some SMD work on similar era boards, this is the first Mac I’ve recapped.

My plans for upgrades are to upgrade the RAM to 36MB (it came with a 16MB SIMM), the VRAM to 1MB and CPU to a full 68040 and clock it at 33Mhz. See if I can get it within spitting distance of the Quadra 800 I had back in the 90s.
 

Nycturne

New Tinkerer
Dec 18, 2024
5
0
1
Picked up some 26AWG wire and installed the bodges. Not my best work, but all the replaced capacitors beeped out correctly based on the schematic, so time to start putting things back together.

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Put back together in the lower case. The battery is temporary as I’m still waiting on many parts to show up in the mail and so I don’t yet have a CR2032 adapter I can put in these machines. Holiday mail delays.

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And while I only have an ADB mouse at the moment, I can check that it boots and the sound chip is working fine. It’s not quite era-appropriate, but it looks quite good on an OLED monitor with a high quality upscaler.

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Without a keyboard, it is going to be hard to finish setting up the drives. So I’m going to have to wait for the ADB Wombat to show up for next steps. It’s been at the local distribution center since the 18th, so it should be out for delivery very soon. IIe card and the 32MB FPM SIMM are also at the local distribution center. CPU is somewhere between California and here. VRAM should be here in the next week or two.