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help for 8096-sx fix

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help for 8096-sx fix

by emilen72 » Fri Feb 07, 2014 10:21 pm

Hello to all, I'm new here, I'm looking for a tips for fix my old 8096-sk that have some troubles....

The story:

the 8096-sk at power-on show a black screen... the screen is ok 100% because I test it with my 3032

the usual trouble on this machine is the dead rom, but this MB have all the rom and the big IC soldered :(

I have desoldered all the rom, dumped and compared they with the same version taked from zimmer's ftp site... and one has turned out died

but even with a new burned and tested replacement eprom... the black screen still here

after this I have tested the two PIA 6520 and VIA 6522... putted these in the 3032, the VIA is OK but the PIA is all dead, in different way...

in the 3032 the UC7 PIA 6520 control the keyboard and other things and is a good try for the 8096's PIA... fitting in the 3032 the two 8096's PIA, they produce two different behavior: one PIA block the machine at the beginners, the machine stay at the first garbage screen for ever, the second PIA boot the machine but the screen is filled up of random characters as typed from keyboard. Both PIA is defect in different way!

then I power-on the 8096-sk without PIAs and VIA but same back screen :(

the next step was to remove first 16K ram, eight 4116 chip, and put socket in place... due the lack of good 4116 chip I have installed two 4464 with little adapter that link the data line of the 4464 to the relative line on the ram socket, most pin of the 4464 is in the right place only five need to be routed different...

Image

this made a step ahead :o the machine boot, even if with a strange result:

Image

It still show a memory error...

but any ideas because the boot message is triplicated?


With only one 3032's PIA installed in UB12 (keyboard related):
Image

the message remain triplicated but change, show an error... why the error? any idea?

regards
emilen72
 
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