On 1/8/23 14:27, Jeffrey Brace via vcf-midatlantic wrote:
Just reminding everyone that there is another repair workshop this coming Saturday and Sunday January 14 and 15. Signup here: https://docs.google.com/spreadsheets/d/1-CzOmtnbGWwcNc53ewymcAe1Zt5xNTow4cmn...
I've dropped off the OS9 68K system in the CDL. So I know it's there and I don't have to worry about letting the electronics warm to room level. I need to grab the OS9 disks so we can at least try the floppy (note to self, check the drive to see if it works before attempting to read the disks). I had some luck with the Liebert Controller board hacking. I burned a rom with 9600 baud and I'd get a version and prompt (Lilbug 1.0) but every 5s it would restart. Today I unsoldered the old MC6803 and soldered in a new socket, added a Hitachi HD6303 (improved MC6303) and did some searching with out the CPU. Reset sees a low (/RST) every 3s. So there is a watchdog timer setup. I traced it back to a MC14584B (yea!) which is a hex schmidt trigger (what? ;-) ). So I have to do some more tracing but the MC14584B is socketed so I'll build a manual reset circuit and figure out what is going on later. -- Linux Home Automation Neil Cherry kd2zrq@linuxha.com http://www.linuxha.com/ Main site http://linuxha.blogspot.com/ My HA Blog Author of: Linux Smart Homes For Dummies KD2ZRQ