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CelGen

Re-Conquest: Lisa 2/5

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This is actually something I got three years ago but it took until today to get it back to an operating state. :lisa2:

 

Picked it up in pretty bad shape but for $150 after shipping it was a S T E A L.

 

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Aside from the obvious paint job there was a reasonable amount of battery damage (four traces had to be patched and a 2N3904 was repalced) but otherwise all boards were in the end able to be salvaged. One day I would love to rebuild the battery holder to take four rechargeable AA's that I can remove during prolonged storage. The power supply required the line filters to be replaced, the floppy drive needed a regrease and the analog card was suspect. The screen displayed a raster but showed nothing else even though I could confirm a video signal was indeed being generated. This was fixed by simply twisting the contrast and brightness pots which were reading infinite ohms in their "set and glued at the factory" settings.

The keyboard was also repadded.

The paint was stripped off using the brake fluid method I posted last year.

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The very last problem to fix was why the parallel port was so funky. The lisa waited for disks but could not detect one. My lisa seems the only one to be fitted with a very weird mod where the lines to the parallel port were cut and resistors were added inline. I was finally to restore the parallel port by removing the resistors and bridging the broken traces.

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At first I sourced a Widget drive for my Lisa. Being a 2/5 it lacked the electrical harness so I added one in. I purchased one Widget and a DOA second one from a man that lived about half an hour away. Spent an afternoon trying to get it to work but while it was detecting it it would just reset the drive over and over. This must be part of that limitation in ROM that prevents the 2/5 and 1 from using a Widget. Regardless it's installed in my system anyways but left unpugged.

I secured an untested 10mb ProFile from Volvo242gt which needed the power supply recapped and one side patched up. It managed to break BLU (highest block was 4D00 and it blew past that until the interrupter hit the innermost limit and began blowing errors) but the LOS 3.1 installer formatted and installed to it no problem. I grabbed a generic Mac mouse and threw in an Apple 1200 modem. Aside from an ImageWriter I now have the full Lisa Office Experience.

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I have big plans for this Lisa. It will be used in the future for a vintage computing campaign where I will setup on a street corner and spend several hours performing a list of tasks that include printing hard copies and using the modem and a cellular bluetooth phone bridge to connect to a remote system and retrieve a file. The idea is that people will watch, point and take pictures that will trend on social networking groups. That evening I'll upload a video recorded by a friend that explains WHY I was there and what I was doing.

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Great job!

 

I'd love to have one of these someday, but I think it's too far beyond my budget at this point :(

 

Anyway, good for you for resurrecting it and getting it to working order.

 

c

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Major congrats. The way you guys can resurrect these old machines that are in such a terrible state is just amazing. I saw a board like that I'd just go "Pfft" and chuck it.

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I agree with these guys. Congrats CelGen. I read your VCF thread and others pretty regularly while you went through this. The harder they are to restore, the more you appreciate them in the end.

 

I have a couple of Lisa 2/5s that I had no choice but to put 2/10 I/O boards in because I couldn't get my 2/5 boards back from corrosion (wired bridges and all). I know how hard it is to get those back because I tried everything. You were able to get it back from the dead and I commend you on that!

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with haps, i even made the slot tabs too... I'm not completely sure but i think he said it still doesn't work.

 

That board needed a good bath in 1/2 water and 1/2 vinegar for about 12 hours to get the surface corrosion off. I'm sure CelGen can attest to that ;)

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That restoration is so epic that it deserves to be written up and preserved somewhere in a mainstream site as a model for how it is possible to rehabilitate a scrap, seemingly too-far-gone computer, assuming that it is potentially interesting or important. I mean, even that ghastly black paint got removed.

 

I am not sure where that "somewhere" could be, but kudos. It really shows something about why sad gits like ourselves do this that most of our simpler projects just don't. It is the scale of it that impresses — even more impressive than your last major huzzah, that "completed" IIfx system.

 

I think we need a medal for bravery for that restoration.

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The very last problem to fix was why the parallel port was so funky. The lisa waited for disks but could not detect one. My lisa seems the only one to be fitted with a very weird mod where the lines to the parallel port were cut and resistors were added inline. I was finally to restore the parallel port by removing the resistors and bridging the broken traces.

 

It is weird, but I just got a Lisa board that has the same mod...

LisaSerial.thumb.jpg.30a6d1b7586d16ebd933bcec86402ed7.jpg

 

So you reconnected the traces (the ones that seemed dremel'd out below) and then removed all the resistors (top and bottom?) to fix it?

Any idea what it was done for? Since it was done to at least a couple, it has to have been done for a reason.

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Wow that is very interesting. Did you do any web searches on the mod? The Lisa's seemed to be so in flux even tho the Mac software was written on them. I'd love to hear why this was done.

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Yeah, when I undid the mod I desoldered and removed the resistors, then used telco wire to patch the cuts.

I should of photographed it after but I kinda don't want to completely dismantle the system again.

I really have no idea what the mod does besides add resistance. It's not even a resistor network. It's just a bunch of resistors inline. That I'm aware of there was not changes to the parallel port or ProFile standard either.

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A series resistor in a "transmission line" (basically any long data wire or cable) is a common way of reducing/eliminating signal reflections that might otherwise cause problems. Same concept as the termination resistors on a SCSI bus. So somebody along the way probably thought that mod was helping things.

 

http://www.irctt.com/pdf/Nov_07_Electronic_Products.pdf

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Yeah, but why put resistors on only two of the lines, and cut the others as well? It couldn't just be two of them that are transmission lines.

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For reference, one of my 2/5 motherboards looks like this (sorry for the blurry pics):

 

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The missing resistors are on he top of the board. Sadly, this board doesn't work and the left most resistor on the top of the board fell off.

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