Recent content by pttak

Hi Andy, Where can I get the code for that very cool display on your PET ? Mike

Based on comments from AndyG and Dave I programmed a TMS2532 with the Superpet character ROM contents. With 6809E and new character ROM the unit booted normally in 6502, and ran perfectly in 6809 mode. Success! Unfortunately after leaving it powered up for 10-15 minutes, when I returned...

Dave, Yes the 8032 works correctly now with all chips installed on the combo board but when I switch to 6809 mode I have a full screen as shown and in the left center there is actually a flashing, movable cursor. This is with a 6809E and ROM U49 installed. Thanks. Mike

Thanks very much. Good advice. I ordered a couple "E" I have two 6809s here, plain and E. Unfortunately I don't recall which one came out of the combo board, but I would guess it was the E. I'm pretty sure this board worked when I first got it decades ago. Mike

Hi Dave, I've been taking another crack at fixing the combo board. I had previously removed the 6809 but had never tried removing ROM U49. It happens to be socketed so I removed it and suddenly now the PET mode finally boots with the combo board installed. I downloaded 970020-12 from...

Hi Fred, thanks for response. I'll keep you in mind, but I guess I am not the type to give up so easy so I'll probably give it some more effort. I lived in MSP from '75 to '83. I got all my PET stuff from there back then. Mike

When I remove the combo board the 8032 works fine. I think I will give up and sell the combo board in non-working condition. Any guesses on what a non-working combo board will sell for? I should add, I have all the original language books and all the interface cables, stand-offs, switches...

Still no luck getting combo board to work. 8032 without combo works fine. My 8032 is a version 8032080. Looking at 8032080 sheet 1 of 7, are any of these mods needed for combo board add-on? I did perform the 16 MHz mod (#12)

With the 6809 removed I was able to boot in 6502 mode intermittently. Works sometimes and not others. I have yet to figure out the cause. Unfortunately I believe there are multiple issues on the combo board. On the o-scope I see a lot of + and - transients on both edges of many of the pulses...

I removed the 6809 and tried to boot up in 6502 mode. Then I scoped all 40 pins. I have results here: https://kl6m.com/c/test1.gif I have a reset button installed so I don't have to cycle the power switch. When I press it, I get action on data buss momentarily but quits after a few seconds.

6502 mode: U17 pin8 = +5v U13 pin39 = high U13 pin40 = low 6809 mode U17 pin8 = low U13 pin39 = low U13 pin40 = high

The NoROM line is high with 6502 switch selected. All three 6809 ROM select lines (pin20) U49, U48, U47 are all logic high. When I switch to 6809 only U49 select goes to logic low. Nothing on the display in 6809 position. With romulator installed on the combo board and #13 selected, the...

I modified the 8032 board for the 16MHz clock. I put everything back together and checked NoROM and it is high, enabling the 8032 ROMs. But still no boot. I installed the bitfixer romulator (dip position #2) on the combo board and it boots into the mlm and is stuck...

Hi Dave, Fortunately I have the original ROMs in this unit. I previously burned an EPROM to fix the edit ROM but that was for my other 8032 which is now working fine and set aside. I need to recheck the NoROM status tomorrow, there could be a problem there. (it's going on midnight here so...

Hello Hutch, Thank you very much for the quick response. Yes, two boards. Not an original Superpet. The 8032 is version 8032080. What is the mod you mention? That must be to get 16MHz on pin 6 of the ribbon via pin 35 of the 6502 socket? There is currently no jumper installed on the...