Closed 8501 7501 CPU substitute for C16 plus4 (85MC01)

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MCes

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If you have your old Commodore 16 or plus4 that doesn't work
you will know that the CPU is the first reason for failure on these machines,
pity that the CPU was produced directly by Commodore and therefore nowhere to be found except at prohibitive prices.

Various solutions have been devised to replace the functions of this CPU,
with different costs and features.

The project I propose represents an excellent compromise point between compatibility and cost,
thanks to the use of a CPLD and a NEW C-MOS CPU the absorption of the 85MC01 becomes about one third of the original
stressing less the power supply and lowering the internal temperature of the machine due to less thermal dissipation,
also for the benefit of the other old chips.

The most modern C-MOS versions have removed anomalous CPU behaviors (illegal opcodes)
that unfortunately some programmers have exploited in their software species of recent production,
this means that the programs of the time should run almost all, those of more recent production could sometimes be incompatible.
The stress tests of the 85MC01 were carried out with various games / cartridges / auto-loaders / tapes / disks / jiffydos, etc ... and it never crashed, but I honestly carry this compatibility limit.

For greater peace of mind 85MC01 can be bought, tried, and if it does not satisfy it can be returned
(within 2 weeks) with refund (not shipments).

More details:
https://www.amibay.com/showthread.php?106203-8501-replacement-for-C16-Plus4-work-in-progress

The cost:
29€+untracked shipping cost: PPal "FOR FRIENDS" (I can't be responsible for untracked shipping)
29€+tracked shipping cost + eventual PPal fees: PPal "COMMERCIAL"

This mod will be assembled on request, also on sale elsewhere.



85MC01: batch sold out!

Now the alternatives are:

CPU4C16 & CPU4PLUS4: N-Mos CPU replacement with high sw compatibility shaped for mounting respectively inside C16 & PLUS4,
it's on AmiBay at https://www.amibay.com/showthread.php...-C16-(CPU4C16)

 
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I'm interested in one unit, shipping to Spain.
Interested also in other item from you, please send me paypal details and total price, thanks.
 
Item received, all OK. Positive feedback left.

The CPU is working OK in my plus4. Just a question, when using DIAG264 I get an error on HIGH RAM (Also with a real 8501 CPU).
Loaded some games and all seems to be working, do you know if this could be a RAM failure?

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Item received, all OK. Positive feedback left.

The CPU is working OK in my plus4. Just a question, when using DIAG264 I get an error on HIGH RAM (Also with a real 8501 CPU).
Loaded some games and all seems to be working, do you know if this could be a RAM failure?

It seem a memory chip issue (it appear with both CPU), probably a RAM chip.
The $02 indicate the value of DATA that is not well read, so it appear to be D1 (U12).
My first tentative would be the U12 replacement....

http://www.inchocks.co.uk/commodore/Diag264/

http://plus4world.powweb.com/forum/39516
 
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Intrested in two.. tried to send PM but don't know if it reached you (don't see item in my outbox).
 
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I would like to buy two, either two universal ones, or one for the C16 and the other a universal one. If I understood correctly, the universal should also fit in a C-16 - is that correct?
 
Yes!

85MC01 can fit to both C16 and PLUS4, it don't heat but can't manage the sw that contain illegal opcode (read the starting post).

CPU4C16 can fit only the C16, it heat as the original CPU but can manage also the sw that contain illegal opcode.

My advice is for choosing 1x85MC01 + 1xCPU4C16.
 
Yes!

85MC01 can fit to both C16 and PLUS4, it don't heat but can't manage the sw that contain illegal opcode (read the starting post).

CPU4C16 can fit only the C16, it heat as the original CPU but can manage also the sw that contain illegal opcode.

My advice is for choosing 1x85MC01 + 1xCPU4C16.

Thanks for your reply!
Hmmmm..... why does the CPU4C16 get hot so much?
 
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