Hello, I've been going through some things left to me by a family member, and found these. As I understand it, 6501s are pretty rare, what with Motorola suing MOS back in the day. I have no real use for these, so I was hoping to ask the experts here what they though I should do with them? If you're aware of any computing museums that would be interested, or if there's a market for them, I would appreciate any input.

Images (warning, very large):
https://files.catbox.moe/6u9xvq.jpg
https://files.catbox.moe/d8p9eo.jpg
https://files.catbox.moe/xi9iwi.jpg
https://files.catbox.moe/asb8fr.jpg

I would have gotten a better picture of the die, but I don't have a microscope handy at the moment. I have two of these ones with the hole where the lid should be, I've not found anything on those in my internet searches.

Nice museum pieces. made in 45th week of 1975, early date code. You can find a 6501 with date code of 3475 (34th week of 1975) on Wikipedia. Handle them with cares and keep them in anti-static bag, don't remove it unless you have good static control.
Bill

Welcome! I think these pieces are indeed rare and historically interesting. If you want a good price there is certainly a market but of course you'll need to navigate your way to a trustworthy buyer and a successful transaction.

As Bill says, a (computer history) museum would probably be very interested, although they might not be able to match the open market.

(6 pieces, white ceramic MOS "MCS 6501" chips, one delidded. Marked with datecode 4575)

You won't necessarily reach your buyer on this forum - we're interested in using the chips, broadly speaking, and not necessarily collecting them. I'm sure I've seen chip collector resources elsewhere on the web.

For myself, a good microscopic survey of the delidded chips would be very interesting indeed.

Quick addendum: oddly, the chip in the delidded package doesn't look much at all like a 6502 to me, even a revision A 6502. This has me very confused! A microscope photo would be a big help here.

I've taken the liberty of attaching a thumbnail of your photo.



That said, it does have the general layout of this kind of microprocessor design. But to me it doesn't look like a 6502, 6800 or even 6809.

(The history as I understand it is that MOS set out to produce both the 6501 and 6502, but they have very minor differences on the inside and are essentially the same design with different options. I would very much have expected a 6501 to look very like a 6502 in broad terms.)

Thanks guys for your input! I've gone and found a microscope to take better pictures of the die. It should be noted that, because I don't have the right size objective to fit the whole die in one shot, this is a very crude (it's not even square) composition of ~9 or so photographs, taken with my phone shoved up against the eyepiece. Just thought y'all may find it interesting. I can't say for certain that these delidded ones are indeed 6501s, I just assumed they were, because they were in a padded envelope with the others, marked "antique 6501 chips".
..
https://files.catbox.moe/p2gjvc.jpg (2740x2690)

Certainly interesting! I wonder if it's a calculator chip? It has a ROM.
https://commons.wikimedia.org/wiki/File ... d_1974.jpg

Edit: but the advert shows 28pin chips not 40pin.

Edit: can you tell just by looking that all the delidded chips are the same design?

Oh hang on, at top left is that a part number?

Cranked up the zoom to check and yep, it does appear to be a part number, or batch number. Both delidded chips have the same number (75298). Also present is an MOS logo. Not sure what the "2 34" below and to the right of the P/N is. Maybe batch/panel?

Oh, great - it is indeed a calculator chip, the 7529, in this case revision B. Only thing is, usually seen in a 28 pin package.

COMMODORE: SR7919 (version-2)
Main Components: MOS TECHNOLOGY: MCS7529,

https://www.richis-lab.de/MCS7529.htm
https://www.petervis.com/Calculators/Pr ... ipset.html
https://www.thecommodorecollector.com/c ... i-computer


(The 234 you see are the mask IDs - there are 6 or 7 masks, and each has its own number. But on the silicon only some of the layers will be visible to the eye.)

Very interesting! Wild to think that such a large chip would be used to drive a calculator. Thank you for the information.

I haven't visited this site for a long time and just stumbled on this thread.

I recently watched some very interesting videos on YouTube from the recent Vintage Computer Federation meeting (not sure where). There were a couple of hour long presentations/talks by ex Commodore/MOS employees. There were some fascinating comments about the relationship between Commodore and MOS, who they used to manufacture their calculator chips. Sounds like MOS were so reliant upon orders from Commodore, that Commodore were able to leverage buying MOS (by fair means or foul), which is how MOS came to be part of Commodore, and then were a resource to design and manufacture the VIC and other chips used in the C64.

Welcome back! Good point about MOS being vulnerable to takeover - as I understand it, what pushed them over the edge was the cost of settling the lawsuit with Motorola over the 6501. The net result was more vertical integration for Commodore, among other things. There are some choice phrases in Jimmy Maher's histories, here for example: https://www.filfre.net/2012/04/computer ... he-masses/