Hello all,
Does anyone knows where to find an old Rockwell 6500/11 microcontroller? Recently I bought an old Emax sampler and it use an 6500/11 microcontroller as a scanner MPU/CPU for checking the interface i.e. controlling buttons, diskdrive and so forth. I suspect that the controller are broken because I can't use any buttons at all on the front panel, and the tech manual says that it's the failing part.
I would appreciate very much for any help I can get. Does there exist any substitute (newer version) of the microcontroller?

Thank you in advance

one may be able to build a replacement using 65c02, program rom and ram and glu logic to emulate. The trick is getting the original programming code out of the 6500 because it is locked in.

we can use on the ESQ-1 synthesizers

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Thanks for your answer Nightmaretony!
So it's not possible to use a PROM reader/writer to copy the original program code?

The R6500/11 is a mask programmable device, the code is physically fixed in the chip during manufacture. You can't read it out.

You will need to find a working chip with the same code (from a similar machine broken in a different way) or work out what the function of each pins was and emulate it with a different device, either small 6502 board or a different type of microcontroller (like a Microchip PIC)

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Andrew Jacobs
6502 & PIC Stuff - http://www.obelisk.me.uk/
Cross-Platform 6502/65C02/65816 Macro Assembler - http://www.obelisk.me.uk/dev65/
Open Source Projects - https://github.com/andrew-jacobs

Thank you BitWise!
I do have two other Emax instruments that works with no problem, so I guess I can check out the ROM code on those, but I have never done ROM reading and I don't have equippment for it (as for now). It would be interesting to make some kind of 'piggyback'-board to replace the IC, and the Microchip PIC sounds interesting to use for that. I guess I need to find some information about how to do the whole thing. It would be nice to be able to save old electronic instrument from the scrapyard!
Btw, I have the technical manual for Emax so I guess I have some help there.

The spectrograph on the 40" Nickel telescope at UCO Lick is still run by a 6500/11(piggyback version). There are threats about upgrading, but for now science is still being done by this 8-bit.

If the microcontroller really is defective then you have a serious problem, for the reasons Nightmaretony and Bitwise explained. You can't read out the code, so you need to duplicate its function somehow (!!) or else get another 6500/11 that contains the identical code. But is the microcontroller really defective? Certainly there's room for doubt.

I am not familiar with this exact equipment, but in general I know that malfunctions arise from many possible sources -- bad solder connections and faulty power supplies, to name just two, and the list goes on. Can you tell us more about your testing and observations with the unit, and your own level of troubleshooting experience? Also, was the unit broken when you acquired it? It might be helpful to know the circumstances when the failure first occurred.

How comprehensive is the tech manual? Many I've seen are quite simplistic, and I wouldn't put any faith in them! Even a well-written manual can hardly cover all the possibilities. Can we view the manual online?

What model is the sampler? Is this the sort of unit we're talking about? (Sorry for bombarding you with questions...!)

-- Jeff

pzachary: is your device something like this

Escobar: is your device a lidded ceramic, and could you desolder the lid and get a microscope into play? It's a long shot but not completely impossible to read out the ROM.

According to the datasheet (http://www.buchty.net/ensoniq/files/r6500.pdf) 6500/11 seems to be in the PDIP, not the CERDIP package...

Commodore's 6500/1 (used eg in the 1520 plotter) had some mysterious ROM readout mode, maybe Rockwell's 6500/11 had something similiar. Who knows...

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Practice safe HEX !

The ESQ-1 version is PDIP without the sockets, but as the picture shows, there are the external ROM versions...

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"My biggest dream in life? Building black plywood Habitrails"

Yeah... but they were rather for the development I suppose....
Anyway - I bought some of those 6500/1 (as on the picture above) on Ebay - I simply could not resist

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Practice safe HEX !