Value of brand new, unopened Commodore PET 2001-8N found in basement

[tech58761]

...You can find original 6550 to 2114 adapters. I have a couple.. But doesnt that change it too? I think running a 2001-8 replacing the RAM at the very least is a necessary thing unless you want a paper weight.

If I had the money and room for one of these 2001s, I would definitely want to look at replacing the scarce (bordering on unobtainium) 6550s with relatively common 2114s, and IMHO it would be an easier decision to do so using period-correct hardware than a modern creation.

 

[rhyoraptor]

Unsurprisingly came across more Commodore stuff!

 

[robert_sissco]

Unsurprisingly came across more Commodore stuff!

That is the second new old stock PET Style VIC-20 I have seen (Mine was the first) but sadly the box mine was in was badly damaged, but everything else was new. Still had the protective film over the badges and everything.

 

[toby405]

Too bad this thread went quiet. Anyone know what ended up happening? Would have loved a shot at a NOS PET.

 

[circa77]

I tell you, the hand-drawn traces on the Kim-1s are beauty; a real work of art in their own way.

I just ran across this posting completely by accident (because I have a couple of KIMs on the bench at the moment), and have to say that it's one of the kookiest things I've ever read (in a good way, no insult intended). Those curvy traces weren't actually "hand-drawn", but they were "hand-taped". In case you weren't there at the time, prior to affordable CAD systems, PCB artwork was taped up, usually on a sheet of clear mylar (for temperature- and humidity-stability) at 2x actual size, because it was easier to work at that scale and the size of errors was reduced after photoreduction to the 1x tooling. There were basically two ways to do this tape-up: You could use black tape, in which case you had to do a separate sheet for each PCB layer (for obvious reasons), and be very careful about your sheet-to-sheet registration - and if you were doing more than two layers, you had to do them in black. The other way was to use black "symbols" for the pads and vias (remember, almost everything was through-hole back then), and join them all up with a clear red tape for one side, and a clear blue tape for the other. Then the photo-reduction to final tooling would also be a photo-separation - you'd send them one master artwork sheet and you'd get two negatives back - one for each side. But here's the thing: While you could bend the black tape into curves, the red and blue tapes were rigid, so each time you changed directions you'd cut the tape at the necessary angle and overlay to continue the run. So what I see when I look at the traces on the KIM is not necessarily "beauty" (though I accept your view of it), but information telling me how the board was laid out.

Myself, I think I only ever taped up a couple of single-sided boards with black tape before switching to the coloured tape for all the boards I did for about the next seven years, before moving to my first DOS-based CAD system. But I'll tell you, there was real magic in spending weeks over a light table, taping up red+blue at double-size, then sending out the artwork and having the finished boards come back at half the size I laid them out - and being able to see the separated layers for the first time!

And there was pretty much one company that owned the entire PCB drafting space back then, Bishop Graphics. And in the early 80s they must have seen the writing on the wall and tried to bring out a CAD system, but it didn't catch on as the others did, and they pretty much disappeared overnight. I still have their catalogs and reference manual (and even a bunch of the tapes and pads and stuff, though they've probably dried up over the decades - I'll have to check), and will you lookit that... there's one later catalog at TIA:

Bishop PCB Design Aids Catalog 109 1992 : Free Download, Borrow, and Streaming : Internet Archive

Bishop PCB Design Aids Catalog 109 1992

archive.org

I'm surprised they were still around that late - must have been close to the end. And at 36 pages it's a shadow of the catalogs they put out at their peak. I really should scan one of the older ones, the kids should be able to see what we went through.

Now, hand taping a board? That'd be some real retro-computing action!

Jonathan

 

[rhyoraptor]

I feel like I learned so much from the people on this thread and I thank you all for commenting. I figured I would add an update as I just came across another interesting find.
A couple of you mentioned that the earlier KIM-1s with ceramic chips were more desirable. I came across this MOS KIM-1 (I don't see Commodore anywhere on it) and I also don't see any "REV" on it anywhere. I assume that means it is an early version? Someone also direct messaged me to look for white chips with early numbers on them because a certain ROR bug was on them. These seem to be early chips but I don't really have much knowledge of this. If any of you have any information on what to look for exactly, I would love the feedback!

 

[daver2]

You have a 6502 CPU. Not an A revision or later, so it is the very earliest production.

This is good for originality...

This 6502 either doesn't have the ROR instruction, or it doesn't work as the later revisions of the 6592 CPU does. I am not going to get drawn into this debate though!

Dave

 

[rhyoraptor]

You have a 6502 CPU. Not an A revision or later, so it is the very earliest production.

This is good for originality...

This 6502 either doesn't have the ROR instruction, or it doesn't work as the later revisions of the 6592 CPU does. I am not going to get drawn into this debate though!

Dave

Thank you for the reply! So this chip doesn't likely have the ROR bug? Forgive my ignorance, I'm not even sure what ROR is.

 

[daver2]

ROR = ROtate Right.

The 6502 that you have either:

Does not have this instruction or,
it may have it implemented in a partial manner.

The documentation did not include this instruction. It only appeared in the documentation (and hence the chip) in later variants.

You can write a small test program to see if:

1. Your CPU does anything with the hex code for the ROR instruction instruction itself. And, if it does...

2. Does the instruction work as per the documentation.

The Z80 CPU contained some instruction decodes that did something, just not (sometimes) what you expected. These were not officially documented - so (technically) they should not be used and are not guaranteed to work in the same way on all releases of the silicon, or from second-source manufacturers. However, so far, all Z80 chips appear to contain these undocumented instructions, and they all appear to work the same way...

Is anything a bug if it is not documented in the official documentation? That is a philosophical discussion, and one that has been discussed at length if you do some searching on the internet.

Dave

 

[syzygy]

Terrific piece of history! If, indeed, the 6502 was first released in Sep. 1975, the date code on your CPU [49th week of 1975] puts it within a few months of the earliest ones ever released.

Here is an interesting difference between your board and my Rev B board, which I noticed right away. I wonder how many other differences are there.

Yours



Rev B

 

[rhyoraptor]

Thabk you for ROR = ROtate Right.

The 6502 that you have either:

Does not have this instruction or,
it may have it implemented in a partial manner.

The documentation did not include this instruction. It only appeared in the documentation (and hence the chip) in later variants.

You can write a small test program to see if:

1. Your CPU does anything with the hex code for the ROR instruction instruction itself. And, if it does...

2. Does the instruction work as per the documentation.

The Z80 CPU contained some instruction decodes that did something, just not (sometimes) what you expected. These were not officially documented - so (technically) they should not be used and are not guaranteed to work in the same way on all releases of the silicon, or from second-source manufacturers. However, so far, all Z80 chips appear to contain these undocumented instructions, and they all appear to work the same way...

Is anything a bug if it is not documented in the official documentation? That is a philosophical discussion, and one that has been discussed at length if you do some searching on the internet.

Dave

Thank you for that explanation. I am intrigued though I will likely not apply power to this unit (since I am inexperienced and don't want to damage it) and will sell it as is and let someone else figure out how the 6502 responds. I imagine there's someone out there who'd like to dabble around with it.

The debate whether something is a bug when it isn't in the official documentation is one I am familiar with, though! What a deep rabbit hole that can lead to.

 

[rhyoraptor]

Terrific piece of history! If, indeed, the 6502 was first released in Sep. 1975, the date code on your CPU [49th week of 1975] puts it within a few months of the earliest ones ever released.

Here is an interesting difference between your board and my Rev B board, which I noticed right away. I wonder how many other differences are there.

Yours
View attachment 1279539


Rev B
View attachment 1279540

Very interesting! I guess it makes sense that each revision was different from the last.
Also does the serial number "0187" have anything to do with how early this board was released? Do the KIM-1 serial numbers even refer to production numbers?

 

[daver2]

>>> since I am inexperienced and don't want to damage it

If you are inexperienced, you certainly should not power up the board - for fear of damaging it (as you state).

However, if you are going to sell it, you will not get 'top dollar' for it if you can't demonstrate it working...

One (or both) of the 6530 devices could be faulty (the usual suspects) and these are virtually impossible to replace - due to the scarcity of them today. Only a finite number of each was produced.

Another philosophical dilemma!

Dave

 

[rhyoraptor]

One (or both) of the 6530 devices could be faulty (the usual suspects) and these are virtually impossible to replace - due to the scarcity of them today. Only a finite number of each was produced.

Are you saying the white ones are scarce or both the black and white ones (and are they different besides color)? In the house I am clearing out, I have access to many (maybe 10-20 at least) of the black 6530 ones. I know all of the Commodore KIM-1s here have them and I have seen some extra ones in boxes as well. But if this particular unit requires the white ones then I have not found extras of those, yet.
I may be able to find someone up here who has more knowledge of these things and can help me power it on. It would be awesome to be able to say it works!

 

[syzygy]

Very interesting! I guess it makes sense that each revision was different from the last.
Also does the serial number "0187" have anything to do with how early this board was released? Do the KIM-1 serial numbers even refer to production numbers?

Although a KIM-1 was my very first computer, I am not a hard core expert and there are many out there.

It looks to me like you have an original KIM-1. By "original" I mean, the first production model of the board and that is about as original as you can get. The dates on the chip are consistent with that conclusion.

Go here and look at the prototype and then the first production model (which looks like yours and notably does not have the diode above the 3 resistors). After that, you see a Rev A and B and others. To me, you have an example of an original production model - 'no revision'.

There are many KIM-1s out there. Many more people want one and their prices are extraordinarily high because of the rich history the 6502, MOS technology and the KIM-1 played in the development of the home computer. Rarity always has to be qualified with demand. In this case, both are present.

Concerning the "ROR" bug; of course your chip has that, as it absolutely should. It is not a problem.

Now, what @daver2 says is absolutely true. If it works as it is, that is, without repair, it is a very big plus.

Given the prices that KIM-1s have gone for recently on the bay; I think yours will go for over 2K if it is working and all the history holds up, possibly more than that - 3K. That is my opinion only and I am not offering you any $$$ at all for it; but that is the question I think that you want answered.

A dilemma? Hah, all of us would love to have such dilemmas.

I say don't do anything at all until you learn more about the piece - maybe send the photos to a few folks. Do not power it up or let someone else muck with it until you have a good idea of what you want to do.

PS: If you have any paperwork/manuals/receipt etc..tell us about that.

So....what are you going to do?

 

[rhyoraptor]

Although a KIM-1 was my very first computer, I am not a hard core expert and there are many out there.

It looks to me like you have an original KIM-1. By "original" I mean, the first production model of the board and that is about as original as you can get. The dates on the chip are consistent with that conclusion.

Go here and look at the prototype and then the first production model (which looks like yours and notably does not have the diode above the 3 resistors). After that, you see a Rev A and B and others. To me, you have an example of an original production model - 'no revision'.

There are many KIM-1s out there. Many more people want one and their prices are extraordinarily high because of the rich history the 6502, MOS technology and the KIM-1 played in the development of the home computer. Rarity always has to be qualified with demand. In this case, both are present.

Concerning the "ROR" bug; of course your chip has that, as it absolutely should. It is not a problem.

Now, what @daver2 says is absolutely true. If it works as it is, that is, without repair, it is a very big plus.

Given the prices that KIM-1s have gone for recently on the bay; I think yours will go for over 2K if it is working and all the history holds up, possibly more than that - 3K. That is my opinion only and I am not offering you any $$$ at all for it; but that is the question I think that you want answered.

A dilemma? Hah, all of us would love to have such dilemmas.

I say don't do anything at all until you learn more about the piece - maybe send the photos to a few folks. Do not power it up or let someone else muck with it until you have a good idea of what you want to do.

PS: If you have any paperwork/manuals/receipt etc..tell us about that.

So....what are you going to do?

Thanks for the info!
As for what I will do, I will probably look around to see if its box is still somewhere in the house like all of the other KIM-1s in their boxes (shown/mentioned in previous posts). This one was sitting inside a non-original box with no other materials but I have found plenty of KIM-1 manuals that I could put with this unit if I wanted the package to contain more than just the board. Not sure if the original manuals that would have come with this unit are different from the manuals that came with the Commodore KIM-1 units, though.
I am hesitant to mess around with the power and I am not necessarily in it to get the most money possible so I will likely just sell as is.
I have successfully sold some of the KIM-1s to people who direct messaged me on here and also on ebay so far and I am happy with how it is all going.

 

[syzygy]

Thanks for the info!
As for what I will do, I will probably look around to see if its box is still somewhere in the house like all of the other KIM-1s in their boxes (shown/mentioned in previous posts). This one was sitting inside a non-original box with no other materials but I have found plenty of KIM-1 manuals that I could put with this unit if I wanted the package to contain more than just the board. Not sure if the original manuals that would have come with this unit are different from the manuals that came with the Commodore KIM-1 units, though.
I am hesitant to mess around with the power and I am not necessarily in it to get the most money possible so I will likely just sell as is.
I have successfully sold some of the KIM-1s to people who direct messaged me on here and also on ebay so far and I am happy with how it is all going.

I think that you have a pretty reasonable approach. While once you sell something, the buyer can do whatever they want, but it is nice when such an item can get connected to a true collector. I would be silly if I said I didn't want it - I would love it, but I don't need it...it's just that it is exactly what the first folks buying a KIM-1 got and that is quite cool.

Referencing the importance of the documentation; it is especially notable if it is original to that early machine. I don't know what kind of docs they sold the initial model with. You would probably be able to tell by the earliest copyright. The general KIM-1 docs have been online for a while but it would be important, I think, to find out if there is some earlier version that could be in your stash.

...and congrats on such a great haul

 

[syzygy]

Concerning the "ROR" bug; of course your chip has that, as it absolutely should. It is not a problem.

So, to avoid needless conflict on this point - I don't know. I went back and did some reading and watching (Bill Mensch discussing it). It was left out but the opcode still did something / it was fixed before released / wasn't in the 1975 op code list but added in 1976 / it didn't work right at first- I just don't know what the definitive story is. My point was that it seems like it is not important in the sense that whatever situation was appropriate for the production date of the chip is ok.

 

[daver2]

As to the 6530 part of your question. These parts have mask programmed ROM inside them and there were only a limited number of parts ever made. You can't buy 'blank' ones and program them yourself (like you can with ROMs, EPROMs etc.).

The white ceramic ones are (generally) more desirable to purchasers than the other types. Although if you have 'real' 6530 parts (of the correct type - see later) you can sell these individually to people with dead ones.

Because the correct 6530 parts are difficult to find, adapter boards have been designed to keep the KIMs running. But they are not 'original' of course.

Because the 6530 contains a ROM element (and both of the 6530s on the KIM have different contents in this respect) the part numbers are actually 6530-002 and 6530-003.

There are many other 6530 parts available, but (if they don't have the correct number after the 6530 designation) they are no good, because they do not have the correct ROM contents.

Just out of interest, I am looking for a 6530-004 part. You wouldn't happen to have one of those would you?

Dave

 

[daver2]

The only real 'use' for the ROR bug is to prove that the chip you are buying from a vendor as an early 1975 6502 has not been relabled and is genuine...

Dave