Re: Help diagnosing problem.

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 http://lisafaq.sunder.net 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 lisa.sunder.net/books.html Received on 2008-05-02 13:35:04