Identifying mystery macintosh SE Accelerator/upgrade card

[lsi-aigisx86]

Hey ya'll

For context: About a day ago I had picked up a macintosh SE off of marketplace for about ~100$ with a keyboard and a few ADB mice, the computer was sold as for parts but was in otherwise in good condition, I got home and plugged it in on my bench and it didn't boot properly, showing the dreaded jail bars with no chime, I decided to take a crack at repairing it and took it apart. After sliding the logic board out, I noticed that the PDS slot contained a rather large card that has a 68030 CPU on it along with some ram and an FPGA, just for testing, I removed the card and plugged the board back in, and it seemed to boot fine with out the upgrade card, so that's mystery solved, the analog board, power supply, and motherboard's caps and battery all looked fine (although I will keep an eye on those).

After playing around with the SE, I turned my attention to the upgrade card and I couldn't find any markings on who made it or what it's specifications are, it also seemed to have a header for a vga output port, which was mounted to the back of the SE30, so I'm assuming that this might be able to do video out or something.

Either way, I've attached photos of the card and the failure it produces on startup.

Does anybody know what the card is or what's wrong with it, and how I might be able to go about repairing it? Thanks.

 

[GreenBar0n]

Looks like the Mobius 030 without the FPU - found halfway down this page:

68k Accelerators, FPUs and other CPUs – Steve's Blog

From the above link:

MU 1993.06 (photo) Pinouts

Mobius 030: SE, Classic (25, 33MHz, opt FPU, 16MB)​

by Mobius Technologies Inc., Emeryville CA (TIL04628)
Clip on, Extended Video

• Drivers: driver, GEMStart Universal 7.1, Connectix Compact Virtual
• Manuals: manual
• Reviews: MW 1991.07, Byte 1993.02, MW 1993.06
• News: CW 1991.04, CW 1991.08
• Ads: MW 1991.11 (photo), MU 1992.05 (photo), MU 1992.10 (photo), MU 1993.06 (photo) MW 1993.07 (photo)
• Discussion: uridium at 68kMLA.org (discussion of pinouts for video)

 

[GreenBar0n]

Regarding the Mobius not working: looks like you have the 25MHz version and according to Page 7 of the manual listed above, I'd guess you're having a memory issue. The manual says you need to have all the same size and type SIMM modules, it looks like you have two different types in there. Maybe try a matching quad set.

 

[Garrett]

That's the first time I've ever seen a 68EC030 in use on a Mac. Was the lack of MMU acceptable on a machine that shipped with a 68000 CPU? Unsure if that's the cause of any issues but interesting to see nonetheless.

 

[phipli]

Yeah, as others have said that looks like a Mobius.

You can either use their drivers, or the GemStart driver works just fine with it too.

That's the first time I've ever seen a 68EC030 in use on a Mac. Was the lack of MMU acceptable on a machine that shipped with a 68000 CPU? Unsure if that's the cause of any issues but interesting to see nonetheless.

Yeah, my Mobius came with a 68EC030 too. They don't need the MMU unless you're doing something that needs Virtual. I swapped a proper 030 into mine. I believe you can actually boot a later Mac with a 68EC040 in some PDS upgrades in a IIci or whatever, it just limits you to 8MB of RAM if I remember.

 

[phipli]

seemed to have a header for a vga output port, which was mounted to the back of the SE30, so I'm assuming that this might be able to do video out or something.

I'd be suprised if it was VGA - are you sure it doesn't have 9 pins?

It does do video out - depending on the option yours came with... pause... yours is a Full Page Display (portrait) version I think, with the 57MHz clock. Some did Two Page Display, but they have something around a 100MHz clock in the same location.

I've not bothered getting mine to do video - mine is also Full Page, it is a bit of a funny resolution and doesn't work very well on any of the monitors I own because it is taller than it is wide.

 

[phipli]

Does anybody know what the card is or what's wrong with it, and how I might be able to go about repairing it? Thanks.

I would assume the card has memory that worked at some point and is set up right. My assumptions would be that the contacts on the connector need cleaning, or that the PSU is a little bit weak and the voltage drops just too low with the card installed.

Install the card, power on and then use a multimeter to measure the voltage between one of the lugs and the 5th hole in from the top left on the foppy drive port on the back of the SE. Let us know what it is. You might need to... cough... stick a large paperclip in the hole on the floppy port. Take super care not to short it to anything, including any of the metal housing of the port, or things go bang.

 

[lsi-aigisx86]

Wow, good stuff everyone, I'll probably take phipli's suggestion and clean/reseat the accelerator card, or maybe swap the memory from my SE's motherboard onto it to see if it works, I don't know if the SE itself needs memory when it has an accelerator installed, the documentation suggests it doesn't, But I don't have any spare 30 pin memory, the guy I bought it from did mention that it used to work and just sat for a long time, so bad contacts/sagging voltage/failed memory is the likely culprit, As for the video out, I don't really care for it, I prefer this to just stay an all in one machine.

I won't have much time to tinker with this until tomorrow night, but in the near future I do plan to max this thing out, ideally I'd want to swap in 4 4mb SIMMs so I can have 16mb of ram, along with swapping in a 68882 FPU for moar floating point performance. But I'll update when I get off work and get time.


In the mean time, any suggestions for pimpin' out my SE?