Re: lisa 2 startup problems

YES I was right, one of the 444C-3 memory chips is bad, I just did not want to wait for new chips and installed sockets on the io board, so I could swap the memory from the IO board of the LISA 2/10 and voila, the ROM is seen correct.

Now I only have to make a boot floppy to start it up :)

Problem remains with the CPU Board, I think I will try finding some RAM chips for this board also because I think those might be also bad :(

As Dexter says " This was a fine day for science :)) "

marți, 8 ianuarie 2013, 19:55:11 UTC+2, Alex a scris:
>
> Hello all,
>
> First of all, thank you for the schematics, it really helped. I took the
> time and checked every connection between all pins of the floppy controller
> part, swapped and changed the 6522 for good working ones and no luck. At
> least I can now rule out a short circuit or a bad solder joint. For the
> moment, the only thing I can think of is one of the static ram chips 444c-3
> is damaged. I also noticed, one of the two chips is made by NEC and the
> other one is SCM, on the IO Board from my LISA 2/10, the two 444c-3 are
> socket-ed and both NEC chips. (this must be the reason why they socket-ed
> the chips). I think one of the two 444c-3 must have been already changed by
> the previous owner of the Lisa (I am starting to think this was a Lisa
> assembled out of non working parts :( ). Now I only have to find two good
> 444c-3 chips to test with them. I will install sockets for those to be
> easily changed if necessary.
>
> If anybody has other ideas about other possible sources for this error I
> am happy to hear about :)
>
> Have a nice evening!
> Alex
>
>

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