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I was more thinking about disassembling the Commodore ROMs. The fact that I could set the year to 23 in BIOS and DOS completely ignores it is interesting ...

The error message is Invalid Date. I have tried every combination of 2 and 4 digit entries and mixing around the MM-DD as well. In the BIOS itself, it only allows 2 digits for the year and I was able to set that to anything I wanted to while in the BIOS setup. But regardless of the value I...

I have tried MS-DOS 3.2, MS-DOS 6.22 and PC DOS 7.

Oh - so you have a Commodore PC 40-III with the BIOS ROM's I mentioned and were able to set the date using DOS and the setup tool?

FYI - I figured out a way to do this. You'll first need a working network card installed. Then using mTCP, I was able to run "sntp -set pool.ntp.org" and it successfully updated CMOS to the correct date and time.

I have a PC 40-III with BIOS ROM versions 390339-05 / 390340-05. These appear to be the latest versions that I was able to locate on Zimmers. The system is an 80286 AT. I am able to set the correct time in CMOS but the date uses a 2 digit year format so going past 1999 doesn't seem possible...

Hi all, I'm looking for a Commodore TV Game unit (either the 2000K or 3000H model is fine). If you have one available, please feel free to reach out. Thanks!

Just to close out on the original question for this thread: I sourced some TMS2532JL EPROMS, burned various 4K ROMS on them, placed them in socket UD12 on my PET 4032 and they all worked fine. Thanks everyone for all the tips and pointers.

I think you're right about there not being an equivalent EEPROM. This website discusses doing a mod to the 28 pin variants to use in the TI-994A. Should also work for this purpose but I don't think I will go this route and just stick to EPROMs...

Hugo - I just took a look at the source code for the DOS Wedge and it does in fact support Eprom at both $9000 and $A000. The binary for the ROM is not in the D64 image but in the ZIP file. You can download it here: http://petsd.net/wedge.php It's a 4K binary (but the code does not use up...

That would be one example that looks interesting and something to try out but I'm writing my own software.

Hi folks, I'm looking to burn a 4K ROM to put in one of the PET 4032 option sockets (i.e. $9000). Any recommendations on which EPROM(s) would be best to use for this nowadays? Thanks!

Here you go :)

Doh! - Sorry - I forgot to mention a couple of things: Based on your note on the transformer - I double checked the ones I was using. Turns out the one that produced the picture that was wavy was for a 9" CRT (tags 9 and 10 were connected as you correctly pointed out). So yes, it was being...

Firstly, I want to express my gratitude for all the assistance and guidance. Hugo and Dave you really helped me out - thank you! Long story short - after confirming all the transformer wiring was correct, etc. the theory discussion you folks were having led me to do a bunch of reading on how...

Gif of display in action below. I would describe it as drifting down the sides.

I measured resistance across R901 and R902 and it was 25 Ohms. C901 measures 25.5 VDC D901 measures 25 VDC across +- terminals and the AC terminals read 10.5 VAC and 11.9 VDC I went ahead and again replaced IC901 but still no change. And there was a typo above - TP1 measured 0.5 mVAC. (not...

Coincidentally, I had just replaced D901, C901, C902, C721 and IC901. The wavy picture existed before I replaced those parts and remained the same after I replaced those parts. I did just check TP1 with a meter and it does read 17.75VDC and 0.5VAC What I find very strange is that the...

Swapping out the power supply meant that I literally switched out the PET power supply - not just the supply for the VDU. In terms of the circuit for the VDU, here is what I have:

Well it seems to be indeed the power supply. I swapped it out with a known good one and it came up. But now I have another issue. The display is waving around almost like it is floating about. When I increase the brightness, you can see what I mean by the waves that are flowing: