Binary Dinosaurs Computer Museum
titlebar
button1Museum History button2Museum Updates button3BinarySaurs on Twitter button4Adverts&Reviews button5Moan, Bitch, Gripe scroll1
button6Inhabitants button7Reviews button8WOW! button9Contact button10Recursion 2017 scroll2
button11Links button12Search button13BDonFacebook button14CGE-UK 2004 button15WROCC 2006 scroll3
base blank_textbox

Tandy TRS80 MIII
Yep, an excellent condition Model III (the followup to the Model 1) with 16K of memory and the ubiquitous Z80 processor, which came from the US with the missus a couple of years ago along with a printer, tape recorder and dust covers. Pity some heavy-handed baggage handler decided to play football with it at the airport, so when it was unpacked here it was obvious the screen had been smashed so I fixed the mountings (as you can see in the pic) and it was put on a shelf until I could get another screen.
Recenty I discovered that the screens were the same as old B&W tellies, and I just happened to have one.....
Screen transplanted successfully; power up and I get raster lines. Dammit. Just as I switch off the magic smoke escaped - I'd totally forgotten the machine was from the US so the PSU was set to 115 Volts and I'd just fed it 240. Oops. Fortunately I could 'borrow' one of the PSUs from my 48K Model III and do some checks and component swaps; after days of desoldering and checking every single component that was testable (99% of the bloody thing) I discovered that I'd killed the main voltage regulator, mains smoothing capacitors (where the smoke escaped from) and nothing else, which isn't bad when you consider that in 115V mode the incoming voltage is fed through a voltage doubler, so pretty much every component up to the regulator had had twice it's expected voltage.
After all that I fully expected the machine to be dead, but it's perfectly happy......thanks again to Tony Duell for help on troubleshooting the PSU :o)
Pictures

All images and text © Adrian Graham 1999-2017 unless otherwise noted using words. Also on