Refreshing a Quadra 605

[Nycturne]

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:

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]

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.

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.

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.

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.

 

[Nycturne]

Everything but the VRAM has shown up. So I followed up with a few more modifications to the system:

- Installed a full MC68040 and 50x50x15mm heat sink.
- Installed a Noctua A6x15 FLX fan to get a little more airflow in the case (rated at 14CFM vs 11CFM of the original).
- Installed an Apple IIe card.
- Upgraded the RAM SIMM to 32MB.
- Swapped the SD card I was using as the BlueSCSI doesn't seem to like the extra Sony card I had, unfortunately.

I also went ahead and configured Total Replay for the Apple IIe card, and played with overclocking. Because I've got the MC88920, I'm not expecting to be able to push the system as far as others have, but the goal for me is to just try to catch up with a Quadra 800 (a computer I had growing up). I still need to move the R96 resistor, but it looks like 33Mhz is stable, while above that is not (I was trying 36Mhz when I started getting disk-related hangs). So at some point soon, I'll need to pull out the logic board and do the resistor swap so I can eke out an extra 10% or so.

Played around with a 3D printed duct for the fan to more directly pull air across the heat sink that others have created. However, I noticed that air flow dropped noticeably when the duct was installed, meaning that the air is more directed, but there is much less of it. I decided to remove the duct and let the system run as it was designed: negative pressure pulling air across the CPU (and heatsink). It works.

It's been years since I've messed around with an Apple II, and it's been a bit of a blast rediscovering some of the old games I used to play. Some I had completely forgotten about, like Apple Cider Spider and The Caves of Frietag. I did have some initial trouble because I forgot that upper-case was the default for the Apple II, and so if you don't have caps lock on when playing games, it can seem like the input is broken. Even better, my current USB keyboard doesn't even have Caps Lock. Guess I'm adding that back to the keymap.

And since we just had Christmas, I broke out a copy of X-Mas Lemmings (1992). The difficulty jump at Level 3 is exactly like I remember.

Now if I could figure out why Ambrosia says EV: Override is playable on a 68040 (recommended but not required), when the game gets some really gnarly slowdowns on the 605...

I just want to call out @OneGeekArmy for Disk Jockey, as I was about to embark on a journey of compiling Total Replay using a custom blank ProDOS partition image, and using 'dd' to inject it into my System 7 drive image before I realized Disk Jockey can combine partition images into a drive image. So thanks for making this sort of thing simpler to accomplish.

Also thanks to @phipli for their work on the software OC tool for these machines, and Mustermann for their investigation into the clock generator chips. It's honestly great to be able to adjust the clock generator like this in a way that is easily reversible.

 

[Nycturne]

While I wait on the VRAM, I’ve been working on the upscaling side of my setup.

Right now I’m using an Amazon bought VGA adapter, feeding into a Retrotink 4K, outputting to a 4K OLED. Yes, the 4K is expensive, but it supports upscaling VGA and DVI/HDMI, and it’s been a great tool to have with my retro consoles as well.

Anyways, I’ve been spending a little time configuring custom input modes and a profile for the Quadra 605 using this VGA adapter. So far it handles 640x480 and 832x624 perfectly, and you can switch between them at will. Need to play with seeing which mode on the adapter covers the most ground of the different modes these older machines support. The idea is that I’d like to polish this profile enough to share it with the wider community, as it should work with most Apple machines that use the DB-15 video port, and make it possible to jump between different resolutions using the single profile.

I’ve also been doing the same with a Quicksilver G4 I picked up, but that’s a story for a different thread.

EDIT: Posted the profiles I've been building to http://retrotink.biticus.net

 

[Nycturne]

Been a while since the last update, but a few things have happened:

* Got the 1MB VRAM in from Europe.
* Ordered some OS-CON capacitors to replace the under-rated solid Tantalums that came in the kit I bought (20V Tantalums for 12V filter caps? That’s not great).
* Finally decided to move the SCSI clock jumper.

I had managed to corrupt the drive images on the BlueSCSI badly enough that the machine could no longer boot because I was playing with the overclock while the SCSI clock jumper hadn’t been moved yet. Had to restore the images from a backup from before installing the software overclock to get the machine booting again. Always keep a backup.

I’ll just say that while the SCSI clock jumper move went mostly smoothly, I absolutely hate the placement of the thing considering how much space there is on this board otherwise. I removed the speaker header to avoid damaging it. With a little patience I did get it done. Since I had the logic board out anyways, I replaced most of the Tantalum caps with OS-CON capacitors. The sound chip’s bypass capacitors (which form a cheap bi-polar capacitor) I left in place because 3 of the 4 leads were bodges. After replacing the 5V SCSI filter cap which required a bodge, I just decided against doing more of that for the moment.

Beeped everything out to check my work, and then booted everything up. Did some SCSI performance tests just to make sure the SCSI bus was stable at 12.5 Mhz, reinstalled the overclock, and did more performance tests. SCSI performance looks good, and things seem more stable. No hangs so far. Since I do have a 50mm square heatsink on the chip already, decided to see how high this 88920 would let me go. Looks like 38.5Mhz. Good enough. The goal was to get this machine in the ballpark of a Quadra 800, and I think I’ve done that. 40Mhz would be “great”, but not required for this machine.

One weird thing that I noticed with this machine, is that I get slightly better performance from the BlueSCSI attached to the external SCSI port than the internal one. Even tried a couple different brands of SD card on the internal BlueSCSI and made sure both had the same firmware (the latest). 4.2MB/sec read, 3.1MB/sec write on the internal (max). 5.0MB/sec read and 3.0MB/sec on the external. Not sure what that means, and it’s still plenty fast, so… not terribly interested in doing a deep dive here on my own time.