Mac Classic II - thin line

[Flamingtoasters]

I recently purchased a Mac Classic II from ebay. At first, the computer did not boot with no startup or death chimes and no video. After washing the logic board, the startup chime is heard and a thick horizontal line flashes erratically. Does anybody have any idea as to what is occurring? :?:

 

[porter]

Find the classicmac2.pdf, I think you are going to need a Torx screwdriver and a soldering iron.

 

[macgeek417]

After washing the logic board, the startup chime is heard an a thick horizontal line flashes erratically.

Replace the caps?

 

[Flamingtoasters]

I don't think replacing the motherboard caps will solve the video problem, it appears to be an analog board issue. If I move the Mac a little, the video will sometimes appear, albeit distorted and squished. I think its a cracked solder joint, but I don't know where.

Other than that, the Mac seems to work well; it has system 7 loaded w/ 4 megs of RAM.

 

[porter]

Find the classicmac2.pdf

The very first thing it recommends is resoldering a couple of big connectors on the analog board.

 

[macgeek417]

You said that it didn't work until washing the board. If I remember correctly, failure to work prior t washing is a symptom of cap goo.

The weird lines are the RAM check, if i remember correctly.

And use System 6 - best MacOS ever!

 

[Flamingtoasters]

Find the classicmac2.pdf

The very first thing it recommends is resoldering a couple of big connectors on the analog board.

Will do. I'll have to look at it tomorrow, as I have recently used it and I want to avoid being shocked. The PDF suggests looking at the yoke connector and the larger capacitors. Another guide suggests similar solutions.

Good thing it can run 6.0.8L, I don't think 4 megs is enough for a speedy system 7.

 

[macgeek417]

Try holding down the mouse while its starting up. see if it boots normally then. if it does, its just the RAM check.

 

[porter]

Good thing it can run 6.0.8L, I don't think 4 megs is enough for a speedy system 7.

Back in 1991 System 7 was the bees' knees on a Mac Plus!

 

[Flamingtoasters]

Try holding down the mouse while its starting up. see if it boots normally then. if it does, its just the RAM check.

I know its not the RAM check because the screen is not displaying anything anymore. As I mentioned earlier, by slightly shaking the computer I can get the CRT to display something. But it is usually just a faint horizontal line. I might be able to upload some photos later.

BTW, I've noticed there is a lack of Classic/Classic II repair information on the web. I guess nobody has ever taken the time to compile a good list of common issues (besides washing the motherboard).

 

[macgeek417]

see http://68kmla.org/forums/viewtopic.php?t=8397

EDIT: Oh, wait - you posted that!

It may be something similar.

 

[Flamingtoasters]

see http://68kmla.org/forums/viewtopic.php?t=8397
EDIT: Oh, wait - you posted that!

Haha yup, that's me

I see your point, though. I could probably apply what was suggested for my Color Classic with this Classic II.

 

[macgeek417]

You should still probebly replace the caps

 

[Flamingtoasters]

Well, after inspecting the analog board and re-soldering some of the components, the video still does not appear. I decided to purchase an inexpensive board on ebay as a replacement but I still want to find a solution for the broken one. Has anyone experienced this issue before?

 

[beachycove]

Are you quite sure that the logic board was properly cleaned? The goo is surprisingly stubborn, and a light soak and swish might not suffice. You might want to have a good look at the logic board in bright light, preferably with a magnifying glass, checking around the surface mount chips. If you have residual goo, you have your problem: the current would then be going everywhere in general rather than somewhere in particular.

I have brushed around the goo (lightly) under running water with a soft toothbrush and had good results — most recently on an 840av, but also on a Classic II. Rubbing alcohol and a Q-tip also seems to do the trick.

 

[Flamingtoasters]

Are you quite sure that the logic board was properly cleaned? The goo is surprisingly stubborn, and a light soak and swish might not suffice. You might want to have a good look at the logic board in bright light, preferably with a magnifying glass, checking around the surface mount chips. If you have residual goo, you have your problem: the current would then be going everywhere in general rather than somewhere in particular.
I have brushed around the goo (lightly) under running water with a soft toothbrush and had good results — most recently on an 840av, but also on a Classic II. Rubbing alcohol and a Q-tip also seems to do the trick.

I can wash it more thoroughly and see what happens. I will eventually need to replace the caps on it to fix this problem. Is there anything I should be aware of before I attempt to recap it?