I'd like to replace my currently MOS 6502 in my Apple 1. Anyone have any idea where I can source one? Willing to pay a decent penny or trade a date code 3675 MOS 6502 for it (plus I'll add some cash).

Thanks!

Neal

Any particular reason you're looking to source a Synertek CPU? Over the years, I've replaced most of the MOS 6502 chips in the Vic-20s and Commodore disk drives (1541 and 1581) with Rockwell R65C02 and everything works fine, albeit they draw less current.

I have a Synertek 6502 in the SYM-1, which is buried up in the attic somewhere.... however, I would likely recommend grabbing an older Rockwell or GTE CPU chip as you probably have a better chance of finding these.

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Regards, KM
https://github.com/floobydust

What's the difference in current draw between the two? (IIRC, the Rockwell NMOS chips I tested pulled about 115 mA.)

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Curt J. Sampson - github.com/0cjs

I've not actually measured it, but according to my original Rockwell datasheet marked as Rev. 3, October 1984, the R65C02 consumes 4ma/Mhz. So with the Vic-20 clock being a bit over 1MHz, it's around 4ma. I have a few Vic-20 machines... most have been fully socketed and all of the chips replaced with CMOS versions, sans the original ROMS, the VIC 6560 chip and of course the 2114 memory. It does run much cooler!

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Regards, KM
https://github.com/floobydust

Oh, whoops! I misread "R65C02" as "R6502"! I thought that one might be able to use power usage to tell the difference between MOS and Rockwell NMOS parts.

BTW, for an R65C02 4 mA is about right, or at least that's approximately what my three sink when run with NOPs at 1 MHz. I didn't notice an increase at 2 MHz or 4 MHz, but possibly I just wasn't paying attention. (And none of my real parts are actually 4 MHz parts anyway, or at least not marked as such. The only ones I have marked as 4 MHz are actually relabled NMOS parts.)

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Curt J. Sampson - github.com/0cjs

trade-ya,

Is it an actual Apple 1 or a repo?

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Cat; the other white meat.

I have an actual Apple 1 #91 in the registry. I'm looking for the Synertek simply because it's rarer and I believe makes my Apple 1 more valuable if anyone knows how I can source one. Thank you!