Lisa 2 (Mac XL) Screen showing multiple images - test-drb@ccmp.vtda.org

16 Aug 2009

On 7 Aug 2009, at 18:00, cctalk-request at classiccmp.org wrote:

...
  Date: Thu, 06 Aug 2009 17:13:53 -0400
 From: Ray Arachelian <ray at arachelian.com>

 Roger Holmes wrote:
  I've taken my old Lisa 2 home after a few
years disuse and tried it
 out. It currently has MacWorks installed on the hard disc and it
 booted fine but the screen has a problem, it shows three smudged menu
 bars equally spaced down the screen and it also has fairly bright fly
 back lines at about 30 degree angles.

 I have the official spares kit for it but never went on the training
 course as I programmed them, someone else who has now left the
 company, repaired them.

 Is this likely to be a minor logic fault in the video generation
 circuitry, presumably on the I/O board, or there is a small board in
 the spares kit which handles the high tension for the screen, is it
 more likely to be that?

 How do I get at the HT board? Do I have to remove the four screws at
 the front of the CRT? It seems unlikely Apple would have made
 engineers do that but how else can I get into the HT enclosure?  Unplug all cables
from the back.
 Unlock the back panel by twisting the two screw locks, and pull it  
 down.
 Next find the two thumb indentations under the Lisa display in the
 front, push up and remove the front panel.
 Next remove the top of the case.

 You'll find the analog card right behind the CRT.  It's accessible  
 from
 the top.

 You can crush a small bit of cardboard - a small crumpled slice of one
 of those fall out subscription cards from magazines will work nicely.

 Reconnect the power & mouse.

 In the front, there's a small power cut off switch around where the
 thumb indentation on the front of the case is, jam the bit cardboard  
 in
 there.  There's another one in the back near where one of the thumb
 screw locks is.  Doing so will allow you to turn the Lisa on with the
 case off and adjust the pots on the analog board.

 If you've had the screen modification kit (ROM version will show as
 3A/88 or 3A/A8), you may have a transformer between the analog board  
 and
 the CRT.  Perhaps this is related to the issue.

 Problems could be anywhere from the VS ROM on the I/O board, or the
 signals from the I/O board going out through the motherboard to the
 analogboard, and also in the power supply.

 Before you do much else, I'd disconnect the I/O board, and motherboard
 and clean out the contacts.  Ditto for the power supply.  Usual
 anti-static precautions apply to the card cage/motherboard.
 After you do that, and whatever you've used to clean the contacts is  
 dry
 and clean, play with the pots on the analog board (I've had good luck
 with DeOxit, other stuff works too, as does a rubber eraser - but
 caution there as these can cause static buildup and might scrape the
 contacts off if they're worn.)

 The pots on the analog board are usually glued down so note their
 position before touching them, and be careful not to crack them, or
 you'll have yet another part to replace. :-)  wiggling them around  
 with
 a screw driver gently is best - if you can find a plastic tipped  
 one, so
 much the better, or if not shave down a plastic knife into the shape  
 of
 a flathead screwdriver so you don't electrocute yourself, or short
 something out by accident.  (I've personally used metal ones and have
 been careful, so YMMV.)

 If it's not a 2/10 (if it has an external parallel port on the
 motherboard) make sure it no longer has the AA NiCad batteries, if it
 does and they've leaked, they could have damaged the I/O board.

 Usual warnings about electrocution and causing damage to the Lisa
 through shorts apply, but you sound like you know what you're doing so
 I'll spare the usual broiler plate babble about the dangers of  
 touching
 the wrong items while the machine is powered on and frying yourself,  
 etc.

 :)

 Have fun. 
Thank, I now have a fairly solid picture. For a while I thought I had  
zapped it with static as I was getting random patterns on the screen  
and no disk activity. I cleaned all the edge connectors twice, swapped  
the two RAM boards and gave it one last try and it started working  
again. The machine is just loaded with Mac OS, MacPaint and MacWrite.  
I'll try out the floppy drive next, if it works I'll probably load the  
Lisa OS and all the Apps. I have the full set of about ten manuals  
with the floppy disks in the back, I hope they are readable. Not that  
I really used Lisa OS, I used the development environment to write  
software, first for Lisa and later for Mac. In the early days there  
didn't seem to be any libraries for doing things like menus and I even  
wrote the code to save the original pixels then draw a pull down menu  
and do the highlighting as the mouse moved down the menu. Apple  
supplied QuickDraw and the memory management system and the debugger.  
I think there was a 3D library which was useless so we wrote our own,  
including hidden line removal, both on screen and for output to pen  
plotters hung off one of the serial ports or sometimes off a parallel  
card. Was there ever any other interface cards which fitted into the  
three slots?

I suppose I might leave Mac OS on it and load up MacWrite and MacPlot  
(which I wrote) or even an early MacDraft (for which we were European  
distributors and which I still maintain). Maybe I will put Lisa OS on  
the other Lisa when I retrieve it from my brother's shop where I had  
it running stock control, reading from a bar code reader and  
controlling a till (cash register) drawer and printing receipts to an  
Apple dot matrix printer until the whole system was retired.  
Incidentally it replaced an Apple /// doing the same job using a  
floppy auto-changer with five 1.2MB floppy disks in it instead of a  
hard drive. The bar code reader was a one bit input device originally  
hooked up to an Apple ][ but re-connected to parallel cards on the ///  
and then the Lisa and the device driver re-written.

Roger Holmes.

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