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Classic II w/ Classic Logic Board - Need help

applepie

Member
Hi all,

1st post here, Apple user since well, 1984... Just started rebuilding my collection up again (Apple IIe, Apple II GS, Centris 650) and now a Classic II that I got off eBay a few weeks ago. Totally cleaned the board since there were a few caps that leaked.. Got replacements, first time at a recap attempt. Believe that I seeded the new caps correctly. Also notice that the battery must of leaked all over and the holder had been removed.

I get these lines that was also happening on first boot up. The yoke cap had fallen off, so I carefully replaced it, there were no cracks or anything on it. I have removed the logic board a few time to re-clean and double check that all was well, even re-seeded one of the ROMs and cleaned with Detox, still showing these lines and it won't boot up.

Logic Board - 820-0525-B
So, revision B of the Classic logic board.. Check. Should work in a Classic II from what I have read here on the site with others experimenting swapping out the logic board between a Classic and a Classic II and vice versa.

Missing battery & holder, have a holder on order, will this machine boot up without a battery?

Analog Board - 820-0390-03
Not sure if this is the original, would think that it is.


Here's the image that I am still getting after recapping the logic board. Fan spins, hard drive spins, floppy drive has been cleaned, no boot up disks, but I do have a SCSI2SD that I am waiting to hook up once I get the screen fixed.

So, anyone have any ideas of what could be causing this? I checked the analog board and all the caps look good. There is some slight flux residue on the back of the board I think or maybe battery leakage? If I re-solder the yoke connection to the analog board, do I need to discharge the CRT?

Any thoughts or suggestions would be greatly appreciated.

IMG_5462.jpg
 

applepie

Member
Well upon closer inspection with a magnifying glass, seems that the PCB connections near the battery have been wiped clean by battery leak, so looks like this board is DOA.

Anyone have a spare logic board that they are willing to part with?
 

joshc

Well-known member
Welcome to the forum.

The problem you've got there is caused by the analog board, not the logic board.

The analog board needs to be recapped and, with it being a Classic, will most likely need other repairs too.

Classic logic boards can boot fine without a battery.

Can you post pictures of your logic board and analog board please?
 

applepie

Member
Analog board seems fine, no bulging capacitors anywhere.. Here's a photo of the logic board as you can see, beyond repair.

IMG_5511.jpg
 

davidg5678

Well-known member
Unfortunately, this Classic Logic Board has been very badly damaged by battery leakage. I think that it is beyond saving, as many of the traces/VIAs connected to the CPU are damaged. The good news is that there is a project underway to make reproduction Classic Logic Boards. If you save this damaged board, you may be able to reuse many of its undamaged parts to build a brand new logic board in the future. From time to time, replacement OEM logic boards are listed on eBay, but this has become very rare, for many Classic machines have had similar battery damage.

I think that the Analog Board in your computer's chassis is likely also damaged/misconfigured. At the very least, it looks to me like the cut-off brightness control is turned up too high. Unlike the logic board, I think that this could feasibly be repaired.
 

applepie

Member
I'm going to hold on to it, hopefully parts of it can be salvaged and the rest will become Macintosh wall art. Back to hunting for a logic board.
 

joshc

Well-known member
Analog board seems fine, no bulging capacitors anywhere
That doesn't really mean anything I'm afraid - they still leak. They leak from the bottom, they don't tend to bulge on these (just speaking from experience, I've recapped a lot of Classics). As @davidg5678 said, the analog board will need attention too.

That said, that logic board doesn't look good either, rotten vias/traces and a lot of crud around some of the chips.
 

Garrett B

Active member
The problem you've got there is caused by the analog board, not the logic board.
Is this always the case? I have a classic II shell I use for testing classic boards. I have a classic I board and classic II board that both work fine with the shell, but one of the other classic I boards I have displays these retrace lines. I am not saying you're wrong, just thinking there may be more at play in terms of logic board/analog board compatibility.
 

joshc

Well-known member
Is this always the case? I have a classic II shell I use for testing classic boards. I have a classic I board and classic II board that both work fine with the shell, but one of the other classic I boards I have displays these retrace lines. I am not saying you're wrong, just thinking there may be more at play in terms of logic board/analog board compatibility.
Depends on where the fault is, yeah. I think the OP's photo looks like a problem caused by the analog side of things, probably in combination with a faulty logic board which won't be helping what appears on the screen.

Classic II and Classic I boards both work fine with analog boards from either machine, nothing changed with the power/video pinouts between those versions if that's what you mean.

Either way, Classics should be treated with caution at least until both the logic and analog boards have been recapped, and still with caution afterwards as they are rather temperamental machines based on my experience with them.
 
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