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Color Classic w/ Sonnet Presto '040 25mhz accelerator

JC8080

Well-known member
A couple months ago I was browsing Offer Up and ran across a Color Classic. I had never been a huge fan and did not intend to add one to my collection of compact Macs, but I figured what the hell and went ahead and bought it. The case was in good condition with mild yellowing, no damage. The seller didn't know anything about the machine and did not have a power cable or keyboard to power it up, which was fine with me. I did ask them to check and see if the battery had leaked and it had not. I paid $200 for it which wasn't a steal, but not awful.

My plan was to recap the logic board and analog board before I even tried to fire it up. When I got it home, I pulled the LB out to take a look at the condition and found there was a Sonnet Presto '040 25mhz accelerator installed. The LB was in pretty good condition with mild cap leakage. I cleaned it thoroughly and installed new caps, same with the AB. The time came to fire it up, and... nothing. Long story short, I suspect the CUDA chip is bad and started looking for a replacement but ended up buying a recapped LB from @defor. I put that board in and it fired right up to a grey screen with a cursor, so my AB recap had been successful.

Unfortunately the internal HD had failed - it would spin up for about 10 seconds, spin down, and repeat this over and over. The heads never moved. I loaded 7.1 onto my BlueSCSI with the correct enabler and it loaded the OS fine. Once I was convinced the system was working properly, I downloaded the Sonnet Presto driver from MG, installed the driver and card, crossed my fingers and powered it up... It powered up fine but was a bit unstable. It would freeze randomly, and when I tried running diagnostic apps it would often crash. This wasn't good. I was using the v2.0.1 drivers, that was all that I saw with my first search on MG. I was definitely worried something was wrong with the card. Then I ran across another thread where it was mentioned that MG had newer versions of the drivers. I downloaded versions 3.1 and 3.2 and tried both. Long story short again, 3.2 froze on boot every time, with both 7.1 and 7.5.5. 3.1 worked but would crash when I tried to use Snooper or APD to run diagnostics. Eventually I figured out that 3.1 actually seems to be working fine, and I think Snooper 2.0 and APD 1.1.1 just don't like the accelerator. Norton System Info works fine, as do Speedometer 3 & 4, and MacBench 2 & 3. Tattle Tech also correctly identifies the card. The system seems completely stable other than with Snooper and APD. I'm calling that a win.

I ran some benchmarks with MacBench 2.0 with and without the accelerator and compared them to the included LC575 (Mystic) and IIfx. Not surprisingly it is much faster than the stock Color Classic, and much slower than the Mystic. The 16 bit data bus really hurts performance. It does however make the machine plenty fast for regular use, it definitely does not feel slow.

Though I had never gone out actively looking for a Color Classic, I'm glad I ran across this one and picked it up.

Color Classic.jpg
Benchmark 1.jpg
Benchmark 2.jpg
 

pizzigri

Well-known member
Congratulation, that accelerator is basically unobtanium, and worth a pretty penny!
Some nice moneyshots of the LB and the Presto card would be very welcome!
 

JC8080

Well-known member
Congratulation, that accelerator is basically unobtanium, and worth a pretty penny!
Some nice moneyshots of the LB and the Presto card would be very welcome!
Sure I can take some pics. The card is a Presto and not a Presto Plus, so I am not sure if it carries the same value. Without onboard RAM on the Presto the machine is still limited to 10mb. It is a full 68040 and not the sans-FPU 68LC040, so that's nice. Not that I will ever be working with large Excel datasets on my CC, but I suppose it's nice to know I could. :)
 

JC8080

Well-known member
The LEM article I sneakily linked to above talks about using this card in an LC, LC II, and CC. It specifically mentions being able to address 12mb in an LC II, and while it doesn't directly say this is not the case in the LC or CC, it does imply so with the language: "access to 12 MB of memory in an LC II with two 4 MB SIMMs installed, overcoming the normal 10 MB limit. (The LC II has this configuration.)" I have not tried yet, I can pull some 4mb SIMMs out of another machine and check. Currently I have 8mb installed (4mb LB + 2x 2mb SIMMs) since I had some 2mb SIMMs laying around, and I figured that's close enough to the 10mb limit it wasn't worth sourcing 2x 4mb SIMMs just to pick up a total of 2mb RAM.

It would be nice to have a "Colour Classic" badge instead of the "Color Classic" badge just for the fun of it. :)
 

ArbysTPossum

Active member
Necropost, I too have one of these, but it had a 68LC040 on it. I took the time to remove it, installed a full 68040, and it took just fine, FPU works and everything. I thought about adding a socket to the board, but there is absolutely no room in there. It's neat to see one with a full 68040 from the factory.
 

JC8080

Well-known member
Necropost, I too have one of these, but it had a 68LC040 on it. I took the time to remove it, installed a full 68040, and it took just fine, FPU works and everything. I thought about adding a socket to the board, but there is absolutely no room in there. It's neat to see one with a full 68040 from the factory.
Nice, I'm glad you were able to do that swap. Even though I will never do anything with that machine requiring a FPU, it's nice to know it's there.

How hard was it to remove the CPU from the board? The only through-hole CPU I tried to remove was a '030, I gave up because there were some pins that must have gone into the ground plane that I could not get. I'm sure I could have done it with a good desoldering station, but I was worried about putting too much into the CPU and board with just my iron, and combination iron/solder sucker.
 

ArbysTPossum

Active member
The combination of using an iron and one of those handheld solder suckers worked well, and some flux, and a LOT of patience. I kinda want to swap out the clock crystal and see what it will do, maybe bump it up to 33Mhz, but it's still on a 16Mhz bus so I doubt it'll be worth it if it works.
 

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JC8080

Well-known member
I built a couple Performer '030 accelerator clones for a Plus/SE. The math benchmark was actually higher without the crystal (FPU running at the same 16mhz as the CPU) than it was with a 25mhz crystal. If you get around to doing that please post some benchmarks, I'm curious if it would make a difference.
 
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