This is part of a series for the Retro Challenge 2019/3. Visit the index page for all the posts.
Today I tackled the second broken Video Genie (TRS-80 clone). This one has an interesting home-made mod on it too, which I investigate.
The main repair was quick and easy, but it still has a minor fault that I need to investigate.
Here’s a 21 minute video of my repair:
I’ve now ordered spare parts for a permanent fix to both machines (I had borrowed working parts from other machines for the diagnosis).
From RS I got a couple of brand new Z80s – they are still making them! Plus some capacitors and transistors to try to fix the power supply circuit for the cassette deck. I also added some extra transistors for my parts drawer for future repairs:
From eBay I’ve ordered 5 x SRAM chips for the video memory. I only need two (for now), but as they’re no longer made and readily fail, it’s worth having a few in the cupboard!
This listing is for exactly identical chips as removed from one Genie, so I can be reasonably confident they’re correct.