apple Lisa2. One working!! - one to go?

Tony Duell ard at p850ug1.demon.co.uk
Tue Dec 14 13:47:42 CST 2010


> 
> Hi,
> 
> Just an update on this project.  I've found someone local (5 mins drive) who 
> has a Lisa 2/10 in storage plus spare parts and spare boards.  After Xmas 

I am, as ever, in the wrong country. I've never actually seen a Lisa, and 
you seem to ahve access to 4 of them...

> we'll remove the Lisa from storage and I should be able to swap out the IWM 
> and ROM to see if that tells us anything.  His Lisa has a non-working PSU 

I would think it's safe to put untested ICs into your machine, but puting 
anyting into a machine whioch could have PSU provlems seems to be a 
little risky...

However, as (presuambly) you don;'t know these spare chips atr good, if 
the machine still dcesn't work, you dont; know if the problems is 
somewhere else entirely, or it is the ROM 9say), but you've not fitted a 
good one.

> and I have a spare working one so some swapping might be on the cards 
> depending on what's there.

I thought the PSU schematics were available. A lot of faults could be 
_rpeaired_, it's not that complex a supply (althogh SMPSUs are paerhaps 
not that pleasant for beginners to work on, thay have a lot of live 
circuitry ('live' as in 'directly connected to the mains), which will 
giee you a very nasty shock (at best [1] if you do the wrong thing. Oh, 
and making a mistake can also result in lots of expensive power 
transistors failing. 

[1] At worst you won't feel a thing. Ever again.

However,m if you want to have a go at fixing the dead PSU, I cna cuggest 
so things to do there too. Most of which are done with the PSU unplugged 
from the mains.

-tony



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