Post #1056808
2026-04-11 00:01 UTC
My CoCo 3 works again! After hauling it across town to troubleshoot, it inexplicably fixed itself.
It was having signal issues. When connected to my Tandy CM-8 over RGB, it would only display with the second ground pin (pin 2) disconnected, but with a loud buzzing tone. It had this same buzzing when connected to my Portavision CRT over RF. But it worked just fine with my Commodore 1702 over composite. I didn't want to deal with this during my demo, so borrowed JJ's Magnavox CM8562.
When I returned his CM8562 today, I brought along my CoCo and CM-8 to troubleshoot. But when connected them, all the issues were gone! It was able to simultaneously display over RGB, composite, and RF without issues. He suspects the issue was static from the CRT interfering with the computer.
This is the opposite of the demo effect.
#retrocomputing #vintagecomputing
Replies (1)
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@thalia@discuss.systems 2026-04-11 00:10
It wouldn't be a trip to JJ's shop (https://obsoletetech.us) without coming back with some goodies. I picked up an Acecad D-9000 tablet and mouse from the free rack; a bunch of 5.25" floppies to put games on, including one with University of Utah branding and others with bootleg ZORK II and III; a Sony Watchman portable CRT TV; a Quantum SCSI hard drive to replace the one in my Macintosh SE; and the manual for Commodore Music Composer. #vintagecomputing #retrocomputing