Achievement Unlocked: TRS-80 Model 1

[Cheshire Noir]

Hey Folks,

Just got a TRS-80 Model 1, and Expansion Interface to match.

(This was when I got it. It's much cleaner now)

Both parts were dirty, but mostly cleaned up OK. The Model 1 has two dead keys, and one dodgy key, but otherwise seems to boot fine. Unfortunately I have no way (yet) to test the Expansion Interface, as I only got one PSU with the two units.

I'll desolder the malfunctioning keys and see if I can resurrect them shortly. I may need to replace that evil keyboard ribbon cable while I'm at it. We shall see.

 

Open to suggestions on a solution for the second PSU. The first one seems remarkably simple. A 16v transformer and a pair of diodes...

 

Can't wait to get the expander working.

 

Cheers!

 

Chesh

[JasonACT]

Not sure if it's accurate...

 

https://en.wikipedia.org/wiki/TRS-80

 

Quote

The expansion unit requires a second power supply, identical to the base unit power supply. An interior recess holds both supplies.

 

[Cheshire Noir]

Yeah there's space in there for a pair of 110v PSU. (Found the cavity while cleaning it up). The Aussie PSU seems to be about 75% bigger than the US one so mine was plugged into the expansion, but wasn't in the expansion. There's definitely room enough I can hide something in there. 

I was looking at toroidals from Altronics. Not sure the minimum voltage the units will run from, but if they will support ~14V on the DC line, I can power both units from the one toroidal and hide the gubbins in the Expansion Interface. That way I could run both systems from the one wall connection.

 

I'd want to build something with some safety features not found in the stock PSU, such as a fuse, and an on / off switch. I don't really want to case hack it, but it's already in rough shape. I will need to make a decision on that.

 

Chesh