problem with MicroMac accelerator in SE

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KennyPowers

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I just finished cleaning, recapping, and reassembling an SE. It had a MicroMac MultiSpeed accelerator in it when I got it. The machine boots to the '?' disk without the accelerator installed. With the accelerator installed, I get this:

PXL_20220627_001558110.jpg

So I'm guessing one of the SIMMs is bad (I think there are four 1MB SIMMs installed on the accelerator), or there's another fault somewhere. I did replace all 13 surface-mount capacitors on the accelerator, so maybe one of the replacements isn't making a good connection or is bridged, but I doubt it. A couple of the old caps did look like they leaked a little bit, but nothing catastrophic or visible until after they were removed, and none of the nearby traces looked broken. Anyone have any idea where to start with troubleshooting this? I could start removing SIMMs, but I *think* that jumper block above the ROM chip may be for configuring the amount of installed RAM, and I can't find the manual for this thing anywhere.

PXL_20220627_004907051.jpg

PXL_20220627_004918331.jpg
 
retr01

retr01

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Hi! You have an awesome treasure! Wow! :D

KennyPowers said:
A couple of the old caps did look like they leaked a little bit, but nothing catastrophic or visible until after they were removed, and none of the nearby traces looked broken. Anyone have any idea where to start with troubleshooting this?
Click to expand...
Looking at the pic of the board, I can see dried up leaking. Since this is about 30 years old, I'd play it safe and recap. If you would like assistance with recapping, @AmigaOfRochester, @Mac84, or @Branchus would be happy to help you out.
 
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KennyPowers

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retr01 said:
Hi! You have an awesome treasure! Wow! :D


Looking at the pic of the board, I can see dried up leaking. Since this is about 30 years old, I'd play it safe and recap. If you would like assistance with recapping, @AmigaOfRochester, @Mac84, or @Branchus would be happy to help you out.
Click to expand...

KennyPowers said:
I did replace all 13 surface-mount capacitors on the accelerator...
Click to expand...

I did recap it. Those are the new caps. I cleaned off all of the dried up electrolyte that I could. The solder pads were clean and shiny before installing the new caps, but I didn't want to get as "aggressive" with cleaning the traces. That whole board has been cleaned with 99.9% anhydrous alcohol and swabs several times. Some of what you see may be flux residue as well from installing the new caps, though I cleaned it up as best I could.
 
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KennyPowers said:
I did recap it. Those are the new caps. I cleaned off all of the dried up electrolyte that I could. The solder pads were clean and shiny before installing the new caps, but I didn't want to get as "aggressive" with cleaning the traces. That whole board has been cleaned with 99% alcohol and swabs several times.
Click to expand...
Okay. Then, try running with one RAM SIMM at a time until you find it working. It is possible one of those SIMMs are bad. And, sometimes as I am sure you know needs reseating.
 
retr01

retr01

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So, it looks like only two RAM SIMMs? You are right, it should accept up to four RAM SIMMs.

According to MicroMac on their website for this accelerator:

The MultiSpeed adds four SIMM slots to your existing compact Macintosh and provides a high-speed 32-bit wide data path for super fast performance. You are required to install at least four ultra-fast (60ns) 1MB SIMMs onto the MultiSpeed accelerator; however, you can install up to 16MB of system memory on your Plus, SE or Classic so you can run a significantly larger System file and/or more programs simultaneously.​
​
Looks like you should already have at least four RAM SIMMs, 1 MB each on the board. You may have larger SIMMs depending on whoever before you installed.
 
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KennyPowers

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retr01 said:
By the way, it looks like MicroMac's site is still run and running. This page is for the MultiSpeed SE accelerator card you have.
Click to expand...

Ya, I saw that, but unfortunately none of their product manuals are hosted there :(

retr01 said:
Okay. Then, try running with one RAM SIMM at a time until you find it working. It is possible one of those SIMMs are bad. And, sometimes as I am sure you know needs reseating.
Click to expand...

That was my plan, but I didn't know if those jumpers had to be configured a certain way for running fewer than four SIMMs (similar to the RAM jumper on the SE's main logic board), and I'd hate to still get an error simply because I don't have some jumper set right, and not be able to tell if I've removed a bad SIMM or not. Also, it's a pain to pull this thing and reinstall it :)

I did already try reseating all of the SIMMs.
 
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KennyPowers

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retr01 said:
So, it looks like only two RAM SIMMs? You are right, it should accept up to four RAM SIMMs.

According to MicroMac on their website for this accelerator:

The MultiSpeed adds four SIMM slots to your existing compact Macintosh and provides a high-speed 32-bit wide data path for super fast performance. You are required to install at least four ultra-fast (60ns) 1MB SIMMs onto the MultiSpeed accelerator; however, you can install up to 16MB of system memory on your Plus, SE or Classic so you can run a significantly larger System file and/or more programs simultaneously.​
​
Looks like you should already have at least four RAM SIMMs, 1 MB each on the board. You may have larger SIMMs depending on whoever before you installed.
Click to expand...

There are four identical SIMMs installed, two on the front, and two on the back. Identifying the chips on the SIMMS, each SIMM looks to be 1MB.
 
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KennyPowers said:
That was my plan, but I didn't know if those jumpers had to be configured a certain way for running fewer than four SIMMs (similar to the RAM jumper on the SE's main logic board), and I'd hate to still get an error simply because I don't have some jumper set right, and not be able to tell if I've removed a bad SIMM or not. Also, it's a pain to pull this thing and reinstall it :)
Click to expand...
I am sure! :p

Yeah, it looks like it requires four SIMMs of at least 1 MB each. So, it might not work to run the card less than that. I am going to try finding more information.
 
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KennyPowers

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Went looking through this large haul of stuff I got from my dad to see if the box for that accelerator was in there. Got excited when I saw a MicroMac box, but "unfortunately" it was a different accelerator...unused and still sealed in the antistatic bag :p

PXL_20220627_024631385.jpg

There is a IIci in this lot it would work with, but I think there's already an accelerator in the IIci too :D The Mac Classic I restored before this SE also has an 030 accelerator in it...
 
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Wow! :D

According to the MicroMac site:

The award winning MicroMac DiiMO 030 accellerator upgrade speeds up the Mac II family of Macintosh computers with a 50MHz 68030 CPU and an optional 68882 FPU (floating point unit or math coprocessor). The speed-up includes a fast 64KB Level2 or L2 cache to enhance performance.​
​
Available for:​
Macintosh II, Macintosh IIci, Macintosh IIvx, Macintosh IIvi, Macitosh IIsi, Macintosh IIcx, Macintosh IIx,​
Macintosh SE/30,​
Macintosh LCIII,​
Performa 450, Performa 600​
Performa 520, LC 520​

Count how many pins on the PDS connector on the bottom of your specific DiiMO 030 accelerator. That should help you determine which of those Macs will work with.
 
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KennyPowers

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retr01 said:
Wow! :D

According to the MicroMac site:

The award winning MicroMac DiiMO 030 accellerator upgrade speeds up the Mac II family of Macintosh computers with a 50MHz 68030 CPU and an optional 68882 FPU (floating point unit or math coprocessor). The speed-up includes a fast 64KB Level2 or L2 cache to enhance performance.​
​
Available for:​
Macintosh II, Macintosh IIci, Macintosh IIvx, Macintosh IIvi, Macitosh IIsi, Macintosh IIcx, Macintosh IIx,​
Macintosh SE/30,​
Macintosh LCIII,​
Performa 450, Performa 600​
Performa 520, LC 520​

Count how many pins on the PDS connector on the bottom of your specific DiiMO 030 accelerator. That should help you determine which of those Macs will work with.
Click to expand...

It's the DOCI50-FPU, so the MicroMac site says it's for the IIci.

Now if I can just get this MultiSpeed accelerator in the SE working...
 
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Trash80toG4

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Working from blurred, caffeine deprived memory this AM:

DiiMO 030 is installed in the IIci Cache Slot. In the remainder of the the Macintosh II family it would work in an adapter and might in the SE/30 as well. ISTR saving a pic of its low rise SE/30 adapter, though it might be from another mfr?

There's a "full height" passthru equipped SE/30 adapter, that's the one @Bolle cloned and has been producing.

There may have been a DiiMO made in the SE/30 form factor with onboard adaptation? Dunno, too sleepy to research or ransack the files ATM. If so guessing it was an earlier/discontinued product by 1993 or upon release of this one that year?
___________________________________________________________

As for the SE, that's not an Apple error code, such would be a specific bomb chime code upon memory check failure. So the accelerator would appear to be working up to the point of its own memory check? Look up the capacity of the DRAM ICs on the accelerator's SIMMs. WAG is that they are 1MB and at least one is bad. If they are the standard, minimum requirement 1MB SIMMS, swap them onto the SE board and fire it up without the accelerator installed. Methinks you'll get that nasty bomb error code for memory check failure. At that point, it would be SIMM hunting time. :sleep:
 
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