toshiba hx-10 writes alone 7brgoto all time

By Chipyto

Supporter (4)

Chipyto's picture

19-05-2020, 07:29

Hello everybody,
I buyed a bad toshiba hx-10 to repairing.
It writes down all time alone 7brgoto,7brgoto,.... and other times 7r7r7r......, without keyboard.
I´ve checked 74ls145, array resistors, vdg, z80,rom and ay-3-8910, and all is ok.
Did you know what could be?
Could be TCX-1007? or RAM IC´s?

Thank you for your help

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By Nprod

Expert (83)

Nprod's picture

26-05-2020, 15:25

Have you checked the keyboard connector?

By Emphy

Resident (43)

Emphy's picture

26-05-2020, 15:45

What do you mean with: "without keyboard", is it:

1) without having the keyboard connected

or:

2) without pressing any keys

?

By Chipyto

Supporter (4)

Chipyto's picture

28-05-2020, 22:01

Hi everybody,

Yes, i have checked keyboard connector

and, yes, i mean without having the keyboard connect.

Computer writes alone all time, sometimes , 7r,7r7r, another times 7brgoto, in all screen.

It may be TCX-1007 ? Because keyboard goes to it.

Thank you

By Nprod

Expert (83)

Nprod's picture

29-05-2020, 21:43

It's hard to say because the TCX-1007 is unique to the HX-10 series and has no documentation at all.

By Wild_Penguin

Hero (609)

Wild_Penguin's picture

03-06-2020, 12:03

Maybe something shorted? I'd check the keyboard, and matrix chart of the keyboard, if available (however, it should be quite easy to determine just by examining the keyboard). Then check for shorts on the motherboard with the keyboard disconnected, from the keyboard connector. But as you already checked some chips, I presume you have already checked simple shorts this way (a left-over, conducting piece of wire could cause this, for example, if someone has tampered with the computer before). If you find a short, try to examine, if you can find where it is.

But I agree with Nprod. Try to rule out everything else, as I believe there are no replacements for the TCX-1007. But even then, the only way to be 100% sure is to swap the TCX-1007. You could salvage one from another HX-10, which has become botched up to a useless state because of some other reasons, but maybe it makes sense to make your unit a "donor", if this is the case...