MicroMac ThunderCache Pro find

[KennyPowers]

Do you have pictures of your two FPUs?

Here's mine

 

[mg.man]

At least MicroMac gave you a 40Mhz CPU...look what they gave me!

Ouch!

Still...maybe I should try to find a better CPU...

You mentioned you've replaced the oscillator - maybe try a 40Mhz one? Might be cheaper than finding a faster CPU - and would be useful to know if that makes any difference?

 

[zigzagjoe]

I just pulled it out to take a picture of the FPU for @zigzagjoe and decided to peel back the CPU sticker too. At least MicroMac gave you a 40Mhz CPU...look what they gave me!

View attachment 70053

I wonder if that has anything to do with my stability problems? Still, it runs fine until I do something obviously FPU related (math benchmark, etc). I've had zero crashes in games and other apps I've tried. Still...maybe I should try to find a better CPU...

I would say that CPU is 50/50 if it would operate at 50mhz or not. Certain masks like F91C are a shoe-in, they will do 50 regardless of rating. That is a 1.0um shrink - it's certainly better than earlier ones, but I'm not sure if motorola officially certified them for 50.

This is a good source for CPUs: https://www.ebay.com/itm/383977080850
Eric sells legit chips, not remarked and I've had no issues with the 7 or 8 I've gotten from him so far.

Your FPU should have no issues at 50mhz - it's a good mask and rated for it.

 

[KennyPowers]

I would say that CPU is 50/50 if it would operate at 50mhz or not. Certain masks like F91C are a shoe-in, they will do 50 regardless of rating. That is a 1.0um shrink - it's certainly better than earlier ones, but I'm not sure if motorola officially certified them for 50.

This is a good source for CPUs: https://www.ebay.com/itm/383977080850
Eric sells legit chips, not remarked and I've had no issues with the 7 or 8 I've gotten from him so far.

Your FPU should have no issues at 50mhz - it's a good mask and rated for it.

Thanks! I ordered one from him...we'll see how it goes.

 

[KennyPowers]

Thanks! I ordered one from him...we'll see how it goes.

I got the 50Mhz 030 today and installed it onto the ThunderCachePro...the stability problems are gone. Thanks MicroMac

 

[zigzagjoe]

Here's the V1.7 ROM off a ThunderCachePro. Note the string of the actual designer.... Apogee Designs, Inc.

Haven't done any further disassembly. I've got a dud one of these on the bench and figured I'd take a dump while I had the chip off the board. It had 40mhz rated parts for both CPU and FPU, and neither are masks that will reliably do 50mhz...

 

[KennyPowers]

Here's the V1.7 ROM off a ThunderCachePro. Note the string of the actual designer.... Apogee Designs, Inc.

iiiiinteresting...that's the same vendor mentioned in the DeclROM of my mystery LC accelerator

 

[zigzagjoe]

iiiiinteresting...that's the same vendor mentioned in the DeclROM of my mystery LC accelerator

Yep, i noticed that too. Perhaps you should dump the contents of the ROM via slot rom and find out what model it is that way. The ROM had several strings identifying it as a thundercachepro.

 

[KennyPowers]

iiiiinteresting...that's the same vendor mentioned in the DeclROM of my mystery LC accelerator

I now notice some similarities between the two board layouts after knowing they were designed by the same people...the 4 bus transceivers have the same location designators, as do some of the AMD CPLDs and the crystal. I did try the ThunderCachePro driver with the mystery accelerator to see if it would combine the LB and accelerator RAM like with an actual ThunderCachePro, but the driver didn't recognize the board and the system only saw the accelerator's onboard RAM.