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Ral-Clan
March 9th, 2017, 05:22 AM
One of the things I love about the PET is the look of the built in monitor. I love the way it is attached to the chassis (in most models) and has that wonderful white or green phosphor glow.

What happens when the actual tubes of these monitors fail or die? What if the circuit boards are damaged beyond repair? Is it possible to replace the monitors with a non-original part?

I know with the older non CRTC(?) video chip PETs (the 2000/3000 series) there was a product made that would allow the PET video to be fed to an external composite monitor. So for these types of PETs, it would be possible to mount the "guts" of any suitable sized composite monitor inside the PET's monitor chassis and get it to work with such an adapter mounted internally.

However, for the later PETs (particularly the 80 column PETs), I hear they operate not on a 15KHz video signal, but a 20KHz video signal. What kind external monitor could be used with these?

I hope my 8032 (SuperPET) lasts a long time before I have to deal with this type of situation, but it did get me wondering. I have several early 1980s green phosphor monitors (Zenith, etc.) that were probably used with Apple II computers. These have composite inputs. They have the same sized picture tube as the PET has.

I wonder if, theoretically, the tube could be made to work with the PET monitor's circuit board (tube swap), or if the entire guts of one of these stand alone monitors could be put inside the PET chassis and made to function with the video signal from the computer's motherboard.

This also causes me to think of future scenarios - once there are no replacement CRT tubes to source, could a flat panel LCD monitor of appropriate size be put into a PET chassis and made to work with the PET motherboard?

KC9UDX
March 9th, 2017, 05:43 AM
Just about any fully analogue (especially with a CRT) composite monitor is easily adapted to any of the PETs.

I've seen (even recently) some analogue multi-sync (with the full 5 BNC jacks) LCD monitors. But I'm guessing those are very spensive. Even those may not give satisfactory output due to resolution conflict. Some LCD TVs may even sort of work.

sjgray
March 9th, 2017, 08:11 AM
I know with the older non CRTC(?) video chip PETs (the 2000/3000 series) there was a product made that would allow the PET video to be fed to an external composite monitor. So for these types of PETs, it would be possible to mount the "guts" of any suitable sized composite monitor inside the PET's monitor chassis and get it to work with such an adapter mounted internally.

However, for the later PETs (particularly the 80 column PETs), I hear they operate not on a 15KHz video signal, but a 20KHz video signal. What kind external monitor could be used with these?


Yes, you can get a composite adapter on ebay for the 2001 that allows you to connect to a normal NTSC monitor. You can also use that adapter on newer PET's with CRTC controller chip, by re-programming the CRTC to output at NTSC 15KHz (or PAL) frequencies. You also need to invert the video signal.

My edit-rom project: http://www.6502.org/users/sjgray/projects/editrom/index.html

lets you build replacement editor roms so it would boot right to the proper frequency.

A while ago I picked up a couple 12" 4:3 ratio LCD screens, with the intention of one day mounting one into a PET. It won't look original and won't fit with the pet's rounded bezel but should be able to work.

And if you're crazy like me, you could also mount a colour CRT into the PET: http://www.6502.org/users/sjgray/projects/colourpet/index.html

Steve