[Coco] Fixing my "F" board TDP-100...

[Al Hartman]

Came back from the hospital, and had a little energy...

- I swapped the 6809EP chip, no change.

- I swapped the RAM and now it boots to a good screen. But, I can’t type: “? Mem” The computer clears the screen, and prints a “.” when I press the “?”. If I type “PRINT”, IT COMES OUT “PRININT”.

- I resat the keyboard connector (HJL keyboard), no change.

- I swapped the SAM, no change.

- I swapped both 6821 chips, no change.

- If I plug in the RAM CHECKER cartridge, the screen goes into a graphics mode, and displays junk.

- The only chip I haven’t changed is the 6847 VDG. I didn’t have a spare, I need one for the Dragon (I thought I had one), so I ordered two on eBay, and two sets of 64k RAM. I need one for a Coco 2 here, and one for the Dragon. Once I have this working, I’ll test every chip I have and hopefully, I’ll have enough chips to upgrade the “E” board Coco.

It may be that I just need to buy an “F” board Coco and swap the logic board in...

-[ Al ]-