[sdiy] UPD8048C question

[Peter Ullrich]

> I´m repairing a Korg Polysix and I found that its problem
> it seems to be the 8048 micro.
> I put the 8048 of another Polysix and it works perfectly,
> but, when I put a new 8048 (exactly a 8048H) it doesn´t work.
> 
> I don´t know too much about microprocessors, because
> I only repair absolute analog keyboards.
> 
> Questions:
> 
> Is the 8048H an incorrect substitute for the D8048C-345
> (exact number on Polysix chip) ?
> Its necessary to read some Korg memory stored in a 8048
> from another Polysix and to record it in a new one ?

The 8048 is a mask programmed microcontroller - so you need exactly the right 
part (with the keyboard software inside). If you take any other 8048 without 
this software it will not work.

Solution: Take the 8048 from the second keyboard - read out the code (in this 
microcontroller no code protection was possible as far as I know) and copy it 
into an eprom version of the 8048 or 8049.

Ciao
Peter

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                               Ing. Peter Ullrich   
	               Hardware & Software Developer  /  Electronic Musician
                               Private Homepage: http://www.ullrich.at.tt
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