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    PET 4032 replacement CRT (9 inch)

    It's tricky to find the right tube that's compatible electrically and mechanically for mounting. FWIW, There has been one success sourcing replacement parts from an old Zenith TV. This was for an older Chicklet PET with the white phosphor screen though. Link...
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    Commodore PET 3032 fast vertical sync.

    Ahh, yes. I see, that logic is only there for the read/write signal.
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    Commodore PET 3032 fast vertical sync.

    In theory, the MUX should only switch to the CPU address lines when the CPU is actually addressing video RAM. There's some logic with BA11 and SEL8. Unless a program is constantly writing to vRAM, it should only be selected around 60 time a second during the interrupt cycle. But the video...
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    Commodore PET 3032 fast vertical sync.

    I haven't seen that one before, but it looks like an upper bit in the video address counter is failed and it's wrapping around to the start of video ram. Hard to count the spaces from the photo. Video RAM is 1024 bytes on a 40 column PET which is 10 bits 1111111111 If the high bit was stuck...
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    Commodore PET 3032 fast vertical sync.

    I've seen this before. In my case the vSync was at 1MHz due to a floating output from a 74LS08 AND gate at C6 (on my 2001-8) On the 2001N/30xx it might be the LS74 at G8. A floating output from the LS08 AND gate pin 3, would cause that flip-flop to toggle at the clock rate. Could also be the...
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    PET 4032 Keyboard Circuit Board

    Possible the PCB is slightly warped? 200 ohms should be fine. Have you tried a mild abrasive to remove the hardened rubber surface and make the pads more flexible? There are some chemical rejuvenation methods too <https://youtu.be/n9gGz2n-sBU/>
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    Commodore PET and RS232

    Commodore didn't include any serial communications with the PET. Unlike the VIC-20 and C64, device #2 on the PET is a second cassette interface. There was a modem sold that connected via the IEEE 488 port, but no RS232 or serial device. There have been a few programs created that use the same...
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    Value of brand new, unopened Commodore PET 2001-8N found in basement

    It's Commodore, so it totally belongs here. I'd be interested in one of those KIM-1s FWIW, the early KIMs with only the MOS logo, from before Commodore acquired MOS, are generally worth more. Any with white ceramic chips are also worth quite a bit to collectors.
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    PET 2001 keyboard issue + instability

    For rust removal I use a product called "Iron Free". It's a green chemical meant for cars, but it removes rust without damaging the paint. I learned about it from an old Adrian Black video and I've used it many times on a few PETs and PET disk drives. For outdoor use, since it smells really bad...
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    PET 2001 keyboard issue + instability

    I've had one completely stripped and powder-coated, but I'd only do that in extreme cases. For a few spots, if you don't want to paint it, try some automotive wax or protective coating on the bare metal spots to prevent rust.
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    Value of brand new, unopened Commodore PET 2001-8N found in basement

    The tapes may work depending on how they were stored and the brand of tape used. I agree, Ebay with a moderate starting bid and long auction should get you the best price. I would try to include all original items that belong with any of the PETs. The external drive with the full size...
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    Value of brand new, unopened Commodore PET 2001-8N found in basement

    I've seen Blue Label chicklet PETs sell for as high as $2K but not often. Never a late model version like these are. Based on the SN# labels I'd say these are very late '78 or '79 A '78 with the C2N drive like this one would usually go for $700-$1000 but add another $200-$300 for the paperwork...
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    Value of brand new, unopened Commodore PET 2001-8N found in basement

    It depends on the collector really. I know several that prefer earlier production/serial numbers. But a casual collector who doesn't know the difference and just wants one to play around with would probably prefer one that you can still get parts for.
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    Value of brand new, unopened Commodore PET 2001-8N found in basement

    Yeah. Believe it or not, the value of these doesn't matter whether they are working or not. Most repairs are fairly simple and even if it was working when you shipped it, there's no guarantee it will still be working when they get it.
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    Value of brand new, unopened Commodore PET 2001-8N found in basement

    I agree. I'd never buy a 40 year old unopened box. Opening it will not decrease the value. as long as you open it carefully and retain all packing materials so you can put it all back in as it was. You'll also want to ship it in another bigger box to protect the original box. Don't skimp on...
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    PET 2001 keyboard issue + instability

    The Gs mean zero page is fine and the video ram looks fine. On the screen with the countdown, do any of the ROM checksums change? 7800, CCC9, 5045 and 0CA4 every time you run it? On that same screen, try pressing keys. The numbers after KBD should change but only one pair at a time.
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    PET 2001 keyboard issue + instability

    I can't imagine being able to listen to the data recording and tell that it's distorted. The datasette is designed to exceed normal record levels and fully saturate the tape since there's no bias and the signal is digital, audio distortion/clipping is normal since it's all square waves anyway...
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    PET 2001 keyboard issue + instability

    They always require new belts, unless of course the belts were already replaced recently. By "belts on both", do you mean two datasettes or two belts in the same datasette? Which model do you have? (https://blog.hutchins1.net/2020/11/datasettes.html) Head alignment won't affect the drives...
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    PET 2001 keyboard issue + instability

    That's the one I have. Same eraser too.
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    PET 2001 keyboard issue + instability

    That makes sense. That's a super useful diag. Thanks for that. I also glad that Bitfixer could include that in the Romulator, which makes things easy.
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