Open Frame h8 issues

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Ronald West

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Jun 11, 2026, 11:08:22 PMJun 11
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I had a few boards left over from when i had an H:. 8080 Processor, Cassette/Serial board and a 8k memory board i purchased from ebay. 

I found a Less Bird front panel board that says v11, 2009 and had boards manufactured, Populated one and have been trying to get it work. Seems like the processor is running and I can see some waveforms on the board but the display nor keyboard is apparently working. Any one had any issues with these (front panels)?

attached is a picture with the assembly powered up. One thing, the 8080 board has the xcon8 mods on it and the ROM is the XCON8 ROM. the disable ROM line is tied high so don't think that is causing any issues. also the schematic is a bit different than the original so not sure if that is messing with my troubleshooting.

Ron
Preview attachment 20260610_225320.jpgPreview attachment 20260610_225320.jpg 3.3 MB.url

Joseph Travis

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Jun 12, 2026, 9:01:31 AMJun 12
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Hi Ron,

It would be helpful to have a photo of your system in order to see how it is configured.  Something is wrong with the photo you attempted to attach.  A closeup photo of the whole CPU board would also be helpful.

If all you have is the 8080 CPU board, H8-5 Cassette / Serial I/O board and 8K Static RAM board, you need the PAM-8 Monitor ROM.  The XCON8 ROM is for a floppy drive based system and requires more than 8K of RAM and the H8-8 Extended Configuration board.  It is possible that it may (partially) work if the RAM board is addressed to begin at 8K (040.000).

Joe

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glenn.f...@gmail.com

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Jun 12, 2026, 10:26:56 AMJun 12
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All good advice from Joe. If it were me, I’d bring the 8080 board back to original factory configuration and use the original 444-13 PAM8 ROM

https://sebhc.github.io/sebhc/software/Roms/H8Roms.zip

 

The Les Bird front panel board should work just fine (FYI: Norberto developed a somewhat more capable version, so this is the latest:

https://koyado.com/heathkit/New-H8-Website/h8-front-panel.htm )

 

Once it is working you should be able to download and run programs via the cassette interface, even with only 8K ram:

REMarks Issue 5 - 24 January 2022.pdf

 

Hope you can fix whatever the issue was with attaching a picture to your email – it will be good to see exactly how things are configured…

 

  • Glenn
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