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

Terry Stewart terry at webweavers.co.nz
Tue Dec 14 15:57:20 CST 2010


Yes, there is always the possibility that his ROM or IWM is also faulty but 
we'll see what happens.

The PSU "swapping" I was thinking of is that I'll trade him a working Lisa 
PSU if he'll trade a working I/O board (that is assuming he HAS such a board 
in the "spare boards" he mentions).

I actually took the working PSU in question apart last right and replaced 
all six of the old filter capacitors.  These are the ones I've found tend to 
blow and smoke eventually.

Terry

> 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.





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