Re: Dead lisa 2

Hi Thomas,

Nice to hear from you again!

>When I try to start the Lisa, nothing happens, not even a click from the
>speaker or a short glowing lamp in the start button.
>I changed the original I/O Board 620-0117 (with the battery pack) and
>connected a Lisa 2/10 I/O-Board and it works. I thought of a dead I/O Board,
>of course!
>But the strange thin is the fact, that a second I/O-Board 620-0117 I took
>from another Lisa 2 shows the same error!!! Nothing happens at all.

I wonder if the standby power from the power supply is weak... I assume you have a schematic of the I/O board? If not, locate one on the internet.

Check the power around the COPS 421, which is running all the time, and handles the power switching, etc.

U7F buffers the power signals, so it needs good standby power too.

If the batteries on the Lisa 2 I/O boards have leaked, they might have corroded some traces into open circuits. This is common, so both the boards you tested may have the same problem.

>The second part: I have a partially defect I/O Board from a 2/10. The floppy
>doesn't turn, but everything else works, even the write/read head of the
>floppy moves during the boot proceedure. Does anyone know what IC or
>transistor does support the floppy-drive spinning-motor?

Try a different floppy drive. For the 3.5 inch drives, I think the motor control is done in the drive. However, there are motor signals coming from the I/O board... U3E pins 6 & 7, U4F-7 & 9.

Certainly when you shove in a floppy, the drive turns the motor by itself to get the index pin to latch into the floppy's hub. So if you shove in a floppy and the drive doesn't turn at all, the floppy drive is broken.

It could be as simple as the drive doesn't see that you inserted a floppy... there is a little switch or opto-interrupter that is pressed down when a floppy drops down. If the switch is broken, or the floppy doesn't go all the way down, the motor won't turn.

>Please excuse my not really perfect english, I can speak better german or
>french than english

(Lots of us "westerners" have worse english than yours, nein?)

James

James MacPhail                   "Think not of engineering as art,
uo957_at_email.domain.hidden                 but of art as engineering"
Sigma Seven Systems Ltd.
james_at_email.domain.hidden        <http://SigmaSevenSystems.com>

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