[Coco] Tandy MPI 25-3024 and CoCo 1 26-3004a

Michael Miller mvmiller12 at hotmail.com
Wed Apr 22 22:42:19 EDT 2020


So, I recently (well - over a month ago) got a Tandy MPI and a CoCo 1 off of EBay and I finally got a good look at them. Both units are filthy, and both had never been opened. Naturally, I opened them up.

The insides actually looked pretty good - nothing obviously wrong with either unit (no burnt traces, no swollen capacitors, no leaky components). The CoCo 1 is missing the ECB ROM and seems to be a 16K unit with 2 jumpers for 64K. I am definitely going to hook these up to Ye Olde CRT TB and see if they still function, and if so, I am peobably going to retrobrite the MPI. The CoCo1 case will just need to be repainted - the gray paint is worn clean off at the base of the keyboard. It looks like the ECB ROM is still available from Ed's store.

My questions are these:

1) On the 26-3004a mainboard, all I have to do is swap out the RAM chips and change the 2 jumpers for the full 64K?

And

T) Theoretically all that has to be done to upgrade th MPI to CoCo3 compatability (because I eventually want one) is to replace the PAL chip in it. Where does one acquire the updated PAL chip nowadays?

Thanks,
Michael V. Miller


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