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Then perhaps consider using a 2816 EEPROM rather than a 2716 EPROM. Assuming you can find an affordable part from a GB source as they are getting harder to find, most cheap programmers will handle the 2816 but not the 2716 part.

Bow, I just noticed said you don't have a programmer to program the 2716 or 2516 which takes a programming voltage of 25V. An old programmer is usually needed. Send me your mailing address by the mail system in this forum and I will send you programmed 2716 or 2516 with the daver2 pettest code...

Do not use any TI TMS2716 parts. They use a Ebb of -5V. Use can use any 2716 that is compatible with the standard Intel 2716 like the Hitachi, or use the TI 2516 EPROM or equiv. Oddly you can us a 2732 part if you burn the data into the upper half of that 4K part (because pin 21 is A11 input on...

Congratulations, another rare KIM-1 back on in service.

Try this place: https://store.go4retro.com/ieee-cable-adapter/

Hi Eudimorphodon, It's a bit hidden on the lower right of the sheet 1 schematic for the 4040, but /IFC is connected to the 555 timer circuit and will reset the 4040. Whenever I reset the PET, it does recycle the 4040. So the jumper should be left in place to bridge the /IFC signal to the IEEE...

Gary, That is correct, but note that the /Reset signal is not inverted (the 7417 is a non-inverting buffer). The /IFC is also a LOW active signal.

This is a very important point with old logic analyzers. The prices can look very affordable, but without all the cables, pods and flying lead sets, they are useless.

I did not know this. Thanks for the info. My version of WinCUPL only runs on very old Windows like W98 or 32 bit versions of XP and use RS 232. Is this OK for you?

It's good to find a person who can still program the PLS100/82S100 part. This was the first Programmable Logic Device on the market back in the mid 1970's. I have a Data I/O 29B Programmer with the 303A-001 Signetics Programming Adapter. I also have the 303A-101 Signetics H & L Design Adapter...

Excellent troubleshooting.

Hi Philip, Nice to hear from you. I'm impressed you have keep that old Pet working for so long. I remember when you, MikeS and I (plus others) fixed that PET so many many years ago. You took many great scope photos that really helped us find the usual problem (flaky NAND gate?). Looks like you...

Good work daver2 and KevinO...

Daver, no, as Hugo says, it is a BRK (B*) to the Monitor. If /diag was held Low, it would perform a Call to the Monitor. The Program Counter is sometimes in low RAM and sometimes at $Dxxx.I would guess bad ROM or bad zero page RAM.

It is amazing what can be done on a 45 year old first generation home computer by creative people.

Yes, the video board by the PET can pass the 21VDC through its full wave rectifier with minor voltage drop and drive the the voltage regulator chip which outputs the required +18VDC. See Video board schematic http://www.zimmers.net/anonftp/pub/cbm/schematics/computers/pet/8032/321448.gif

That top ROM is stamped 6540-014 and is from a BASIC 1 set and the chip goes into socket H6. Here is the info on that part: H6 901439-06 6540-014 ROM Basic 1 D800-DFFF And note that there are no way to know that this 45 year old part is still working unless it was recently tested.

Yes, the pass thru IEEE port connector is a handy feature.

Whenever I have to do a firmware update on a gadget, I break a sweat thinking of all that can go wrong leaving me in the Twilight Zone.

Perhaps the MAXv2 firmware has been corrupted. Did you try to reload it? It used to be somewhat difficult task requiring an Atmel programmer, but he has added code to do this within his gadget. Of course you may be wary of doing this since the .prg files are working right now, and if the boot...