Toshiba HX-10 PAL weird random characters onscreen

By kbjunkie

Supporter (3)

kbjunkie's picture

06-08-2020, 21:43

Hi All,

I had just finished replacing RAM in my HX-10 and it was working fine - typing away and all...

Then I switched off, came back a while later, switched it on and it boots to basic and immediately types a bunch of keyboard characters on the screen on the first line, ending with GOTO and one character that appears to flash and change to other characters over and over..

Needless to say, typing on the keyboard produces nothing... :-(

Anyone got any ideas? In the absence of any schematics, I'm poking around in the dark! Does anyone know which chips are responsible for the keyboard decoding? Is it going to be the dreaded ULA? Does anyone have a schematic?

Feeling deflated!

Thanks,

KbJ

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By sdsnatcher73

Paragon (1094)

sdsnatcher73's picture

07-08-2020, 11:16

Here is a blogpost about a HX-10 repair. As you have already replaced RAM and the machine seems to work otherwise (and was working before), it may also be the ROM dying slowly (and working sometimes and not other times). Worth a try imho.

By Briqunullus

Master (147)

Briqunullus's picture

07-08-2020, 13:01

I'm not into hardware at all, but to me this seems to be something in the keyboard itself or the connectors to it. The MSX just thinks many keys have been pressed simultaneously (GOTO is just one F3 keypress away) and puts it all on the screen.

By Grauw

Ascended (9272)

Grauw's picture

07-08-2020, 14:17

Please post a picture or video showing the problem.