Re: Help diagnosing problem.

From: Ray Arachelian <ray_at_email.domain.hidden>
Date: Fri, 02 May 2008 22:02:10 -0400

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. Received on 2008-05-02 22:02:10

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