View Full Version : PET 2001 PERSONAL vs PROFESSIONAL

March 6th, 2014, 06:20 PM
Forgive me if this question has been answered already somewhere in here. I can't find it, and I'm a little rushed.

Quick & easy question: Difference(s) between PET 2001 PROFESSIONAL COMPUTER and PERSONAL COMPUTER? (black label)


March 6th, 2014, 06:48 PM
Forgive me if this question has been answered already somewhere in here. I can't find it, and I'm a little rushed.

Quick & easy question: Difference(s) between PET 2001 PROFESSIONAL COMPUTER and PERSONAL COMPUTER? (black label)


Good question. Commodore had many labels for their machines and seemed to switch back and forth from one to another. It doesn't make much sense to go by the label. You need to open up the machines and see what's inside. Commodore developed various motherboards and as far as I know the label won't tell you which is inside, unless it's the very first chicklet model and assuming it was never upgraded.

I have a page of pet labels here:

You can see how they switch from one to the other in various models.


March 6th, 2014, 09:04 PM
You're the one with the PET labels page! I've lost count of the number of times I've visited that page for info. Thank you so much for compiling that and putting it up on a page.

My question was too vague. I'm actually trying to determine if there's any "official" difference between the chiclet models, which I've seen labeled as "PERSONAL" and "PROFESSIONAL." I have yet to discover any materials that shed light on this, even after an exhausting evening of reading everything my various google queries turned up.

Commodore's weird and often inconsistent naming/labeling is kind of maddening.

March 7th, 2014, 04:35 AM
Hey, thanks! Glad you like it.

I think I've stopped trying to figure out the when's and why's of Commodore. They don't seem to make a lot of sense sometime. My goal was just to document the variations.

If you read the forums you'll find you are not alone. Many people are confused about what model has what. I don't think it'll ever be sorted out. You have to remember that the computer industry was young and there were few standards. Everyone just did their own thing. The engineers designed and built then handed the machine to marketing. Marketing then had to figure out how to sell it. I don't think there was much interaction between the two groups...

I probably should have kept the matching machine pictures so you could see what monitor/keyboard/case style the label belonged to. It's all very confusing ;-)


March 7th, 2014, 05:00 PM
Well, whatever the differences may or may not be, I now have a "PROFESSIONAL" PET in my life. He's going to be a challenge, I suspect, since he appears to be in rather rough condition. I'm going to have to spend some time nursing my new faithful companion back to health. No matter what I do, though, he will always remain partially disabled due to a genetic defect known as "chiclet keyboard." We will just have to learn to cope.

Here he is, still at the pound. My new PET, Rusty:


March 7th, 2014, 06:01 PM
Congratulations! And Welcome!

Don't knock the keyboard; it's not that bad to type on (when it works well), it lets you have a one-piece box with integrated tape drive and, maybe best of all, it makes the PET worth more (all things being equal).

There are several versions of the 9" screen 2001 PET but as Steve says, the labels and even the model numbers are not a reliable way to tell what's what; I have two identical 4032 PETs with different model numbers and vice versa, a 4032 can be either of two totally different machines.

There are essentially five versions of the motherboard and it'll be important to establish which one you have when it comes to schematics, replacement chips and advice:

The original 2001 (which is what yours probably is) used static RAM chips and was available in four versions, depending on which combination of RAM and ROM chips it used; the most common seems to have been the 6540/6550 version which unfortunately are by far the most difficult to find these days. You may be lucky; yours looks like a relatively late version of the original PET.

The later 'New' PETs (known as 2001-N, 30xx-x, 40xx-x etc. depending on where they were sold, what version of BASIC they used, etc.) used standard dynamic RAMs and more-or-less-standard ROM chips.

There were three versions of BASIC, equally confusing; the actual version is identified by the symbols on the top line of the startup screen. In the beginning there was BASIC1, which did not work well with the IEEE interface even though one of its chips was upgraded. The last version was BASIC4 which added direct disk I/O commands, among other things; unfortunately it doesn't work 100% on the original static-RAM PETs. The version between 1 and 4 was confusingly known as either BASIC 2, BASIC 3, or just 'Upgrade BASIC'

The first PETs had white phosphor screens and blue labels and screen bezels, and were available in 4K or 8K versions. The white CRTs were replaced with green screens, the labels and bezels became black, the early Sanyo cassette drive was replaced with the one shown in your picture, and of course at some point the keyboard/case and main board were replaced (although not at exactly the same time); as a matter of fact there were upgrade kits available to replace the upper case half and keyboard. Maximum memory went from 4K/8K on the original to 16K/32K in the later Dynamic RAM version, and the later models were available with a 'Business' keyboard instead of the more common 'Graphic' keyboard.

Enjoy, and the keyboard makes it special, not a genetic defect! ;-)

March 8th, 2014, 02:05 AM
Thank you very much for all the info. I have been looking at the various schematics at zimmers.net. I'll receive the PET sometime next week. I don't have any photos of the interior, so I'll be in suspense until then about which board it has.