Re: Help diagnosing problem.

From: Patnukem <patnukem_at_email.domain.hidden>
Date: Fri, 2 May 2008 21:29:16 -0500

actualy that sticker just fell off :), I have two cpu boards and it seemed to act the same way with either one but I have no way of testing them but the one I think looks to be in the best condition does not seem to be missing anything. I would not be surprised if it was the motherboard or the I/O I guess I will have to keep my eye out for a I/O and a motherboard. I did clean all the connectors very well and made sure everything was seated well.


On May 2, 2008, at 9:02 PM, Ray Arachelian wrote:

> Patnukem wrote:
>> I have lots of monitors that I can try I was using a green apple IIe
>> monitor adjusting all the knobs on the monitor to get the picture.
> You'd need something capable of displaying 720x368. If you have Larry
> Pina's book on repairing Mac's, which includes the Lisa chapter, I
> think
> he's got a list of which monitors will work.
>> I do not have a good camera but I took some with a 2mp one I have
>> I figured I would just put them here incase the attachments will not
>> work.
>> there are several of different pictures of the board. I removed the
>> batteries a while ago but have since have tested that all the
>> contacts
>> under and around where the batteries were still work. The two
>> clipped
>> resistors are R41, R47. I will keep testing making sure there is no
>> worn out leads ect.
> I don't see anything too weird other than the sticker being missing
> off
> the 6504's PROM - sadly if this has been removed it could be that the
> ROM was damaged/erased - it normally takes a lot of UV light to do
> that,
> but who knows where this Lisa was stored. The picture isn't too
> clear,
> can you verify if you see a sticker or if you see a window there that
> lets you see into the chip?
>> when turned on I only hear a high pitched sound (High voltage circuit
>> for lisa monitor?) and nothing happens when I push the on button
>> again
>> the power button light stays on. I have re-capped part of the power
>> supply (Before I did it nothing worked on it at all so it is a bit
>> better now)
> So power on is handled by the COP421 microcontroller, for power off,
> the
> 68000 has to work in order to tell the COP421 to shut down the
> machine.
> So your CPU board isn't working, could be because there's no memory or
> other issues.
>> I have tried to turn the monitor potentiometers back and forth to
>> clean them then reset the to about the same place (a little off on
>> purpose to not settle on a possible dead spot) and I have tried a
>> disk
>> in it it will make a mechanical sound for about a second and stop.
> It's normal for the drive to spin the disk for 1 second. Probably
> means
> that part of your I/O board is ok.
>> I forgot to add that when powered up with just the cpu/IO I get no
>> beeps. Could this be cause by the video board? or should I guess its
>> the I/O or the main board that all the cards plug in to. also there
>> are some corroded pars near where the batteries were but it seemed as
>> if I could get continuity though all of them, possibly the board
>> cant.
> Hmm, that's not a good sign that you're getting no beeps. How's your
> CPU board? anything look missing?
> It could be the motherboard. You should unplug all the cards and
> clean
> all the connectors on both the cards and the motherboard with
> something
> like DeOxit.
> >

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