I own a date code 3675 MOS 6502. Bought new and never used. I'm curious how much something like this is worth. I do not plan to sell but just curious.

Thanks!

It could be valuable to a collector. But only a collector would know for sure what it's worth to him.

A 6502 of that vintage will probably be missing the ROR instruction; that's probably the surest means of verifying its authenticity, insofar as it would be from the first year of production. This also makes it relatively useless to the general hobbyist; software for the earliest 6502 machines (eg. KIM-1, Apple 1) often had to include inelegant workarounds for the missing ROR. The Apple II already had access to later 6502 production, with a working ROR instruction included.

Thanks so much for your response. Very interesting and I appreciate the info!

I just looked up the ROR bug as I was curious how bad it was. The ROR instruction was present in the early 6502's, it just worked incorrectly. So the quick fix was to take the instruction out of the manual. And it looks like it was pretty bad, including shifting left rather than right. That's probably just some errors in the microcode PROM, so easily fixed with a chip revision, which they did quite quickly.

I think for the collectors of such things a ceramic 6502 is worth more than a plastic one, and a white ceramic one is worth a lot. This is probably mainly for Apple I collectors where I think they must have used white ceramic 6502's in a lot of the originals. If you every see an old, dead, 6502 computer and it has a white ceramic 6502, it would be well worth salvaging for the 6502 alone. White ceramic 6502's sell for thousands of dollars.

And there are apparently 3 versions of the white ceramic 6502, with different ground layouts.

It might be worth doing some research into your 6502 to see exactly how rare it is.

Thanks for your thoughts. Mine is the MOS white ceramic 6502 brand new. I own an Apple 1 also with a white ceramic 6502 in it but certainly note date code 3675. I don't want to fiddle with my Apple 1 and somehow screw it up. It works nicely and I want to keep it that way. It's #91 on the registry

This is a photo

Could we perhaps regard this thread as closed? Much of the discussion has continued over at

Earliest 6502 Date Code?

(On this forum, it's normal to expect every thread to be seen by every interested party - it's not so busy that we need to cross-post. It's also normal to have long-running threads and to resurrect old threads, so long as the thread stays on topic. It's fine to start a new thread when there's a new idea.)