Re: Help diagnosing problem.

From: Patnukem <patnukem_at_email.domain.hidden>
Date: Fri, 2 May 2008 18:44:04 -0500

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.

On May 2, 2008, at 1:36 PM, 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.
> 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.
> 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)
> I will post more If I find anything else.
> Patrick
> On May 2, 2008, at 12:35 PM, Ray Arachelian wrote:
>> Patnukem wrote:
>>> I will try a disk in there when I get home and see if it tries to
>>> read
>>> there is a red light in the disk drive that lights up when the
>>> computer is on, it does not click at all. the display in the lisa
>>> does not do anything, just the external one, I will try to post a
>>> video of it to show. I have two memory cards and two cpu cards so I
>>> am fairly sure they are not the problems, Like I said before the I/O
>>> card could be it also the main board (the one that holds all the
>>> other
>>> boards) could also be damaged, it looked kinda bad before I cleaned
>>> it. I have put several new caps in the power supply and the
>>> computer
>>> seems to be getting at least some power, I can tell the front and
>>> back switches are working since the computer will turn off when the
>>> front or the back is removed.
>> The Lisa had a very different video display system than most
>> monitors of
>> the time. While the external video connector is an RCA jack, this is
>> not something that can drive most monitors out there. There were a
>> few
>> that would work, however, but odds are, unless you have a display
>> that
>> you know will work with a Lisa, it won't work.
>> For example, taking the output from that RCA jack and connecting it
>> to a
>> modern TV, or a composite monitor (such as those that drove, say a
>> Commodore 64, or an Apple II) will not work.
>> I'm a bit weary of the clipped capacitors you've mentioned earlier,
>> however; those sound like very bad news to me. You'll probably
>> have to
>> resolder those. As far as I know, only 2 resistors were cut from the
>> I/O board to convert it from a Lisa 1 to a Lisa 2 - no other boards
>> in
>> any Lisa should have any cut components.
>> Can you take a high-res picture of whichever board had the cut
>> capacitors, we can compare it to ours and see if we can see what's
>> wrong. I think LisaList will accept attachments - at least last
>> time I
>> checked it did. If not you can email me the photo directly.
>> When you actually press the power switch to turn it on, do you hear
>> any
>> sounds at all? any chirping, or clicking? (Those indicate power
>> supply
>> issues, which can usually be solved by capacitor replacement.)
>> Once powered up, do you hear any beeps? Usually the Lisa will beep
>> 3x
>> when there are issues. The beeps themselves (long/short, low tone or
>> high tone) have meaning and can help diagnose what is wrong. But
>> only
>> if the CPU board and enough of the I/O board work.
>> Once powered up, if you push the power switch, does the Lisa power
>> off?
>> If not, the CPU board might not work either.
>> Meanwhile I'd urge you to go read the various repair parts of
>> as they may give you clues, and also to
>> copy
>> the Lisa schematics to see which components were cut. You can get
>> those
>> most of what you'd need from
>> >>

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