Thanks Chuck for doing such a detailed build, review and testing of the Commodore PET compantion board. Both Rudy and I really appreciate it and your feedback was awesome! I've been using my PET companion board for when I do presentations using my PET 2001-N. It's really nice being able to connect up a external monitor so others can easily see what's going on. I've also connected up to a projector as well and with the CB2 sound mod included, it can be pumped through a rooms PA system too.
Hello Chuck! Super big thanks for looking at and reviewing the PET Companion board. You did a fantastic and honest review and appreciate it. Hopefully, it will also help you when doing PET repairs. Thanks again for sharing
@@MichaelDoornbos Which Commodore PET computer do you have? Rudy did a great job with this board. It's a must-have for any Commodore PET computer owner for sure!
@@geekwithsocialskills I left mine. I kinda like the historical look of the drilled out RAM slots by Commodore. I've got a MiniPET to play with if I want 32k of RAM
See the Addendum video for corrections th-cam.com/video/lnEL1ZqPBHU/w-d-xo.html For those wondering, NTSC frequencies should be 60Hz Vertical (or 59.94Hz for Color), and 15.734 kHz horizontal. The PET derives it's horizontal frequency from the 8MHz clock, divided by 512, so 15.625kHz, which is actually the PAL horizontal frequency. The PET derives it's vertical frequency from 260 horizontal lines which comes out to 60.09615Hz, so it's just a bit faster than NTSC.
It is pretty awesome for sure! Rudy's project was a 12 month +/- work in progress with 7 board revisions, the one Chuck showing being the 7th. It's technically a homebrew solution as well, however Rudy and I along with Chuck and a few others put a ton of time into testing, manual updates, etc. It's not perfect, but works really well and does what it was originally created for.
Looks like a very handy board! I wonder if the too-high voltage on the scope trace is due to the circuit expecting a 75Ω terminating resistor to ground on its output, such as you'd find with a TV/monitor's composite input?
I did some extra testing tonight and my scope has the option for 50 ohm termination which brought the signal down to ~650mV, so I'd guess 75 ohms would put it right around 1v pk-pk. I'll try to adapt a 75 ohm terminator or a combination or resistors to demo this for an addendum video.
At about 20:00 you mention to disconnect the internal monitor of 12" PETs since it won't accept a 15 kHz horizontal frequency. However, my PETSTRIP-game which was originally for 2001 PETs changes the CRTC-registers of 4032 (and 8032) PETs to PET 2001--like values and as such displays a 15 kHz signal. The monitors of both my testers did not blow up and displayed the game just fine (4032 and two 8296). However the 4032-person mentioned some "shimmering" of the image. I would assume the monitor will just not display a picture if you go out of the displayable spectrum.
The 12" inch monitor on the PET works on 20Khz and not 15. You could leave the monitor connected, however, it won't work properly and may damage the internal monitor. It is recommended not to have it connected, but if you use use at your own risk
@@RudysRetroIntel Yes, I realize the CRTC-PETs and the monitors work originally at 20 Khz. Just saying that they will display 15 Khz fine (I could search for the videos my tester sent me). I guess one would have to look at the original monitor manufacturer and what their actual display-ranges (or reccommendations) are. I know that I treated my 1901 monitor with very wild frequencies over the years with the VDC-chip of my C128 and that has not broken down because of that. Certainly a topic to be investigated if wrong frequencies can actually damage the monitor - smelling "Killer Poke" here 🙂
Something else to consider is if the monitors have been recapped or not which could be a factor if things go boom or not. Original 40+ year old capacitors could get pushed over the limit and cause all sorts of issues. As both Rudy and Chuck have said in previous comments, use at your own risk, especially with how hard it's becoming to find Commodore PET computers in nice looking and working condition after so many years.
I asked Steve Gray about this and he said that it will sync to 15KHz as he has seen during testing. I would still recommend users disconnect the internal monitor just as a precaution, unless they need to have both screens active.
I've been interested in this but I have a "chiclet" 2001 and since yours didn't work, I think I'll wait. Please do a follow-up if you can determine why yours didn't work, and whether the board needs a mod or if your PET is having an issue.
It should work on your PET 2001 chiclet keyboard model. Dave Bradley tested it with his PET 2001 chiclet. I'm thinking Chuck has some sort of issue with his PET and will get it sorted. Chuck knows his stuff when it comes to PET computers for sure!
I'll do some checking next weekend but my PET is an early Rev and has had some problems off and on. All the same signals are needed for the RGB2HDMI connection and the timings had to be the same or close for the profile to work. Probably as simple as a low level on one of the signals due to a bad connection on the user port.
I figured out the problem and it works fine on my Chicklet PET. It just wasn't getting power because my early 320081 board doesn't have power or signals on the top side of the tape port connector. I just had to move the power tap wire to the bottom side and it works fine. This would only be a problem on the 1977 320081 board with Synertek ROMs and 6550 RAM. I can't connect external datasettes to it for the same reason.
@@HutchCA Thanks for checking this out! I would have had the same problem. 6 connection fingers on top of J3 that go to nothing. Assuming that all models have the power available on the back side, so they should definitely re-wire the connector in production.
It probably was due to cost and simplicity. The clock is 8Mhz which is needed for the video and then divided down to 1MHz for the CPU. It's doubled to 16Mhz for the 80 column PETs since they have twice the pixels per line. Getting the sync signals to exactly 15.734 kHz and 60Hz would have complicated the design and since they had their own monitor, it wasn't necessary. They got pretty close at 15.625kHz and 60.09615Hz
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Thanks Chuck for doing such a detailed build, review and testing of the Commodore PET compantion board. Both Rudy and I really appreciate it and your feedback was awesome! I've been using my PET companion board for when I do presentations using my PET 2001-N. It's really nice being able to connect up a external monitor so others can easily see what's going on. I've also connected up to a projector as well and with the CB2 sound mod included, it can be pumped through a rooms PA system too.
Looks great. Can't wait to build one.
@@MichaelDoornbos Rudy did a really awesome job of making this happen. It's a must-have for any Commodore PET computer owner.
Hello Chuck! Super big thanks for looking at and reviewing the PET Companion board. You did a fantastic and honest review and appreciate it. Hopefully, it will also help you when doing PET repairs. Thanks again for sharing
Looks great. Can't wait to build one.
@@MichaelDoornbos Which Commodore PET computer do you have? Rudy did a great job with this board. It's a must-have for any Commodore PET computer owner for sure!
@@geekwithsocialskills 2001-8N
@@MichaelDoornbos Nice! Mine is a 2001-16N however I upgraded it to 32K and BASIC 4.0 a couple years ago.
@@geekwithsocialskills I left mine. I kinda like the historical look of the drilled out RAM slots by Commodore. I've got a MiniPET to play with if I want 32k of RAM
See the Addendum video for corrections th-cam.com/video/lnEL1ZqPBHU/w-d-xo.html
For those wondering, NTSC frequencies should be 60Hz Vertical (or 59.94Hz for Color), and 15.734 kHz horizontal.
The PET derives it's horizontal frequency from the 8MHz clock, divided by 512, so 15.625kHz, which is actually the PAL horizontal frequency.
The PET derives it's vertical frequency from 260 horizontal lines which comes out to 60.09615Hz, so it's just a bit faster than NTSC.
I need one of these yesterday!
The boards will be revealed at World of Commodore first, then a web store in 2024. Stay tuned
@@RudysRetroIntel congrats
Nice video (yours and the device output!) 😀
Thank you for serving.
Man, that looks way better than my homebrew solution.
It is pretty awesome for sure! Rudy's project was a 12 month +/- work in progress with 7 board revisions, the one Chuck showing being the 7th. It's technically a homebrew solution as well, however Rudy and I along with Chuck and a few others put a ton of time into testing, manual updates, etc. It's not perfect, but works really well and does what it was originally created for.
Looks like a very handy board! I wonder if the too-high voltage on the scope trace is due to the circuit expecting a 75Ω terminating resistor to ground on its output, such as you'd find with a TV/monitor's composite input?
Good catch. This is probably true since the signal was not loaded at all.
I did some extra testing tonight and my scope has the option for 50 ohm termination which brought the signal down to ~650mV, so I'd guess 75 ohms would put it right around 1v pk-pk.
I'll try to adapt a 75 ohm terminator or a combination or resistors to demo this for an addendum video.
At about 20:00 you mention to disconnect the internal monitor of 12" PETs since it won't accept a 15 kHz horizontal frequency. However, my PETSTRIP-game which was originally for 2001 PETs changes the CRTC-registers of 4032 (and 8032) PETs to PET 2001--like values and as such displays a 15 kHz signal. The monitors of both my testers did not blow up and displayed the game just fine (4032 and two 8296). However the 4032-person mentioned some "shimmering" of the image. I would assume the monitor will just not display a picture if you go out of the displayable spectrum.
The 12" inch monitor on the PET works on 20Khz and not 15. You could leave the monitor connected, however, it won't work properly and may damage the internal monitor. It is recommended not to have it connected, but if you use use at your own risk
@@RudysRetroIntel Yes, I realize the CRTC-PETs and the monitors work originally at 20 Khz. Just saying that they will display 15 Khz fine (I could search for the videos my tester sent me). I guess one would have to look at the original monitor manufacturer and what their actual display-ranges (or reccommendations) are. I know that I treated my 1901 monitor with very wild frequencies over the years with the VDC-chip of my C128 and that has not broken down because of that. Certainly a topic to be investigated if wrong frequencies can actually damage the monitor - smelling "Killer Poke" here 🙂
Something else to consider is if the monitors have been recapped or not which could be a factor if things go boom or not. Original 40+ year old capacitors could get pushed over the limit and cause all sorts of issues. As both Rudy and Chuck have said in previous comments, use at your own risk, especially with how hard it's becoming to find Commodore PET computers in nice looking and working condition after so many years.
I asked Steve Gray about this and he said that it will sync to 15KHz as he has seen during testing. I would still recommend users disconnect the internal monitor just as a precaution, unless they need to have both screens active.
I've been interested in this but I have a "chiclet" 2001 and since yours didn't work, I think I'll wait. Please do a follow-up if you can determine why yours didn't work, and whether the board needs a mod or if your PET is having an issue.
It should work on your PET 2001 chiclet keyboard model. Dave Bradley tested it with his PET 2001 chiclet. I'm thinking Chuck has some sort of issue with his PET and will get it sorted. Chuck knows his stuff when it comes to PET computers for sure!
I'll do some checking next weekend but my PET is an early Rev and has had some problems off and on.
All the same signals are needed for the RGB2HDMI connection and the timings had to be the same or close for the profile to work.
Probably as simple as a low level on one of the signals due to a bad connection on the user port.
I figured out the problem and it works fine on my Chicklet PET. It just wasn't getting power because my early 320081 board doesn't have power or signals on the top side of the tape port connector. I just had to move the power tap wire to the bottom side and it works fine. This would only be a problem on the 1977 320081 board with Synertek ROMs and 6550 RAM.
I can't connect external datasettes to it for the same reason.
@@HutchCA Thanks for checking this out! I would have had the same problem. 6 connection fingers on top of J3 that go to nothing. Assuming that all models have the power available on the back side, so they should definitely re-wire the connector in production.
Does the maker have a webstore? Or do does one simply email them?
Apart from WoC, I don't know. Check with @RudysRetroIntel on his channel.
At this time, there is no web store. However, that may change in Jan 2024
Why wouldn't it have NTSC output?
It probably was due to cost and simplicity.
The clock is 8Mhz which is needed for the video and then divided down to 1MHz for the CPU. It's doubled to 16Mhz for the 80 column PETs since they have twice the pixels per line.
Getting the sync signals to exactly 15.734 kHz and 60Hz would have complicated the design and since they had their own monitor, it wasn't necessary.
They got pretty close at 15.625kHz and 60.09615Hz