toshiba hx-10 writes alone 7brgoto all time

Par Chipyto

Supporter (4)

Portrait de Chipyto

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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Par Nprod

Expert (105)

Portrait de Nprod

26-05-2020, 15:25

Have you checked the keyboard connector?

Par Emphy

Resident (59)

Portrait de Emphy

26-05-2020, 15:45

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

1) without having the keyboard connected


2) without pressing any keys


Par Chipyto

Supporter (4)

Portrait de Chipyto

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

Par Nprod

Expert (105)

Portrait de Nprod

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.

Par Wild_Penguin

Hero (644)

Portrait de Wild_Penguin

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...