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MarNo84

Apple Lisa 2/5 defective Video Output?

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Hi,

 

I have a special problem with a repair project...I wanted to repair a broken Lisa 2/5 motherboard. It was an victim of battery leakage...cleaned everything and fixed the broken traces on the board. I did the best/simple way: wirework - until now, it always worked like a charm.

 

I just uploaded a short demonstration video of the actual behavior/startup. It seems to boot up just fine - seems to pass all diagnostics - typical beeps - but I just get this gray and static screen :-/

 

Here's a short video I uploaded on my channel to demonstrate the behavior:

 

Does anyone has the correct schematics of the motherboard? I could find every schematics of the Lisa - unfortunately, not of that damn little motherboard?

 

I'm sure, it can't be anything big that troubles me here... it has to be between the signal traces to the crt/video unit?

 

What I can see on the motherboard, there are some resistors and all in all 2 capacitors on the board?

 

I need assistance xD Please help me fixing this and getting this beauty up and running again :)

 

These pictures I attached, should show you the condition at first before repair and now, after cleaning and partial fixing - for sure, the screen got much better at all, still broken but better ;)

 

Cheers,

Marcus

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Edited by MarNo84

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I did just fix the traces between the Slots..not the ones for serial connection - this shouldn't be the problem here? I don't need serial ports at all - if everything else is fixed and working, I probably will fix them too.

 

I also checked the CPU-Board, I/O- and as well the RAM-Boards. They all just work fine in my cardcage with my motherboard - the Lisa will boot straight through without any trouble - so it just can be anywehere on that motherboard.

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I looking for the same document.

 

i have more or less the same problem, but the screen doesn't even comes on.

 

the other boards have been tested ok, just like you.

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Can you even recognize the diagnostic beeps? Have you tried the external Video connector - just use an ordinary Apple Monitor // or /// - any other good CRT with FBAS should work too?

 

Hmm I think it's one of these resistors (Pictures attached) - I'm sure the traces are fine...so?

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Hi-Hi-Low as per this indicates the keyboard is unplugged and it can be clearly seen as such in the video.

 

The grey screen with the diagonal lines is a raster. That means the analog board is working well enough that it has horizontal and vertical sweep.

Before you proceed any further, take a sharpie and mark the current positions of the adjustment pots on the top of the analog board. You can see it just behind the CRT when you take the top off.

Turn each pot a little to the left and to the right. I've seen them simply oxide up and the connection goes open but just disturbing the knob brings it back.

 

 

 

Have you tried the external Video connector - just use an ordinary Apple Monitor // or /// - any other good CRT with FBAS should work too?

Short of hacking a multisync monitor to take a composite input, the video out on the back of the Lisa is your standard composite video signal however the vertical refresh rate is non-standard and I couldn't find any conventional or professional video monitor that would sync to it.

Edited by CelGen

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Also want to add you have done a good job cleaning up the backplane and yes, the schematics for it are not available online that I have seen so far (while schematics for every other board are) but thankfully it and the I/O board which is where the battery resides are two-layer boards so there is need to worry about inner layers possibly being damaged.

The dark marring on the edge connectors is fine. If in doubt give them a good rub with a pink eraser.

 

Additionally, unless you have it already planned to do it, I suggest recapping both the power supply AND the analog board.

Edited by CelGen

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Yeah  [ :D]  that was a hell lot to polish away - a few days later after the celaning with that fibreglass pencil, I could feel these little fibreglass things all over my skin xD

 

Just to be curious - every other part of the cardcage is working fine. the cardcage/motherboard I talk about, is not the one of my own Lisa ;) it's a repair project for a friend.

I cleaned and fixed his CPU-, I/O- and RAM-Boards and gave them a fully loaded stresstest with my motherboard in my Lisa computer. Everything works fine - with my motherboard :-/  I also tried reverse with my cards on his motherboard -same result == same sounds and same defective screen.

 

Just to be sure and safe, I unplugged the keyboard and mouse for testing purposes.

Edited by MarNo84

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Again, the analog card is not in the card cage. It's behind the CRT.

 

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While the refresh rate on the rear video output as I mentioned was not something standard you should still be able to make out large features on the screen. Again, the white box will be obvious and you might even be able to see the mouse cursor.

 

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Just plug in a (literally any) composite monitor. Again it will not sync right but you will see something resembling an image.

Edited by CelGen

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Yep, I did the same here - I did it with my 100% working setup in first place and second, with the defective motherboard... surprise, surprise  [:D]]'>   as I can see on the external display, everything works like a charme - even booting up from the external ProFile into LISA OS. Now I'm turned on xD So it's just a simple, little bugger - I hope it's just a damn resistor (one of these few).

 

Right now, I am uploading a short demonstration video on my channel - sorry, I talk in german but it's easy to understand what I'm talking about  [:P]]'>

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Edited by MarNo84

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Hi,

sure, just a few moments ago the upload was completed:  https://youtu.be/G-5XTGIdiIs

 

Excuse my camera movements - this time I didn't use my tripod/stand :-/ it's just a short video of 2 sessions - just a short demonstration of the behavior. It's in gemran language - I will put some subs later to it. When I completely finished this repair project, I will cut a complete 'documentary' of the whole project and repair process  [8D]

Edited by MarNo84

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My guess is that you just adjust the pods at the analog board and you will have stable display of the Lisa monitor. They are reachable if you remove the top lid.

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Yeah, if I would get any kind of working sceen on that CRT I would try these adjustment pods to stableize ;)

 

The fun fact is: if I put MY motherboard with all the cards into THAT Lisa - it works perfectly - even the internal CRT. So,..I doubt it is any wrong adjusted pod on the CRT unit itself? If it is, wouldn't it the same bad screen on my working parts?

 

Anyway I will give it a careful try these days - let's see, I will report back.

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Again, you are seeing a screen raster and good horizontal and vertical geometry. That indicates both the tube is good and the analog board is outputting at the absolute minimum a useable everything (it just has no video signal to show). If the boards and card cage work and give an image in another Lisa it can only mean either a problem with the wire harness or the analog card with my money on the latter.

Rotate the adjustment pots on the card. Yes they may still have the blue locktite intact but that's the same thing I said. All I did was twiddle the brightness adjustment and boom, there was an image.

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Again, you are seeing a screen raster and good horizontal and vertical geometry. That indicates both the tube is good and the analog board is outputting at the absolute minimum a useable everything (it just has no video signal to show). If the boards and card cage work and give an image in another Lisa it can only mean either a problem with the wire harness or the analog card with my money on the latter.

Rotate the adjustment pots on the card. Yes they may still have the blue locktite intact but that's the same thing I said. All I did was twiddle the brightness adjustment and boom, there was an image.

Ahh wait...maybe there was an misunderstanding ;)

I didn't put the cardcage or boards into another working LISA - no, I just used my own LISA to test everything out. I did put the original Setup into my working LISA and there I have the same bad behavior with the CRT output. It is definetly something on that motherboard - not the CRT or adjustment/analogboard or any other part of the CRT/Videoparts of the LISA  :lisa2:  if it would be something with the adjustment or other video parts - well, then my original working card cage would't work either - but it works.

Edited by MarNo84

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Worked on the Lisa board yesterday, removed the I/O connector (a lot of mess from the battery) a lot of traces were not there anymore, so spent part of the day fixing those (have not tested anything yet, but here are some pictures for reference)

 

I have left indicators on the blue paper for reference, 1 goes to 1 and A to A... will let you know once tested.

 

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OMG! Wow - good job ;D  Well, for my serial connections, I assume I have to do the same...- besides my connectors/slots didn't look that much corrodet. What did yours look like? Have any pictures? I will swap the small parts and report back :) ...I don't want to remove the slots }:)

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JUST A QUICK UPDATE: it's alive and running again [ :D

I finally found the bugger...it was just a broken trace between the lines R1 to C15/R15. I measured every part and trace again and finally found a missing signal - so d*mn easy at the end - no parts needed to swap,

Did a quick solder work on that broken trace and everything works like a charme again  :lisa2:

 

The last steps / work to do will be the still cut serial connectors. That's a lot of wirework to do - I will rethink about that - no one needs serial connectors on their LISA? Everything was cleaned and neutralized - so no future damage. Well, I think this is done - any future updates will come here on the forums and on my repair blog / on my homepage and yery soon on my YT channel too - especially that complete repair process was recorded on every important step. Soon I will upload a special repair video on my channel as well.

 

Thank you all for your assistance and your helpful advices :wub:

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Edited by MarNo84

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What a great story and happy end! Please post a link to your YouTube video if ready. I'm looking forward to see it. That you found such a small trace defective is impressive.

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