Broken Mac Classic Logic board

[MacFanClassic]

Hello,

I recently got my first bunch of 68000 based macs. Most of them have not so big problems.

But the Macintosh Classic had it's battery leaked all over the board, I think it's not repairable.

Is it possible to run the board without the RTC, the soundchip and that 9021AV chip? Sorry, I don't have any schematics.

If the Board is unrepairable, is there anything that fits in that case other than Macintosh Classic or Classic II boards?

They seem to be impossible to find....

It just needs to have a ADB input, I don't have a old Mac keyboard...

Thanks...

 

[falen5]

am working on an se30 that had a small acid leak........................2 god dam days metering..............still cant get it going

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acid leak = very very bad news

 

[Macdrone]

Yep bad news. Wish they had left the batteries accessible like on the plus since they did not want you in them.

I think you can't find the boards because of the same issues with others.

Might try unwise ever as he has pretty good luck restoring boards.

 

[MacFanClassic]

Sadly, the board had acid leaked through the copper of the interconnects. I don't know if in that area, traces inbetween layers got harmed too. So my guess this board will be a museum piece. Leaves a working CRT and analogue board...now what to do with it...

 

[techknight]

It's pretty much junk. Time to find another logic board.

 

[Paralel]

If it has eaten through multiple layers of the board, its truly a lost cause. Sorry.

 

[falen5]

take a few pictures and post them.

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has the white lettering on the board turned green around the acid spill area...........that's what happened to mine.

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On mine ive metered out the rom to cpu and reconnected every broken trace - meters out fine...........but still no chime

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what else has to happen for chime?

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is this the startup sequence - 1 cpu asks 'anyone out there' . 2 rom says yep, im here. 3 start initializing video, ram etc etc

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has anybody ever got an se30 back to life after an acid leak...........without osiloscope and schematics? - if so ............tell me HOW YOU DID IT !!!!!!!!

 

[uniserver]

i think techkinght has, but he is the trace whisperer,   

He accesses the third eye, and beams him self as pure energy and flows into the main board and the broken traces visually appear in his consciousness.

 

[techknight]

lol. Yea I did. 

Not fun at all though. 

The address and databus has to be clear in order for ANYTHING AT ALL to happen, for example on the mac portable the SWIM shorts and holds the bus up. 

So theres that, But otherwise, the VIA, VIA2, ASC, and ROM have to be present to get ANY sort of chime. at all. Oh, and the GLU. If ROM meters back to the CPU properly, then you need to test the ASC and VIAs back to the CPU, and the control and select lines back to GLU. 

 

[unity]

Well I dont want to look like I am praying on the poor souls with damaged boards, but I have a stack (literally) of Classic One boards that are in great shape. No Classic II boards though. I can send them to Uniserver for a re-cap and he can ship to you if that is something you want. I am sorta working on other projects, but it would not take me much to test them and find a good one. If you want one direct from me, we can do that too. Just not sure if you have re-cap experience and they always need it.

 

[falen5]

NO NO NO Unity......god darn it.....that's cheating.

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it has to be fixed.................there is no other option............to replace the board is cheating...................LOL!

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ive tried my own form of meditation............to become an electron...........enter the board.........and search for those acid breaks

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......

...............

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then I discovered I couldn't become an electron

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tonight im going to attempt a deep irish meditation, where I become one with the board.............as I become the board , parts of me will break..........these will equate to the breaks in the board

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.........................ehhhhhhhhh

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no

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guess that wont work either

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but

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It must be true about techknight.............(love that picture uniserver)

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and guess what

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I GOT ONE OF THE SE/30'S WORKING.............EDITING THE FOTTAGE.............WEH HEYYYYYYYYYYY!!!!!!!!!!!

 

[techknight]

Vulcan mind melding. There ya go. Lol.

You just have to understand the circuitry and how it works, so when you know the symptoms you can pretty much figure out where to look. Kinda like a doctor. Well good ones anyway.

It comes with experience. I have been repairing electronics since I was 9 years old. 20 years ago. Child prodigy I guess.

 

[uniserver]

Yup unity has some classic boards lol. Sometimes is really nice to slide a motherboard in plug in the connectors turn on the power switch and it just works. it's a beautiful thing

 

[GnatGoSplat]

It could probably be fixed, but it's a lot of work.  There's a good chance the vias are eaten through and the solder joints and traces are corroded.

I attempted to fix one a few years ago.  Managed to get it to boot, but it has issues.  My thread with carnage and attempted repair pics:

https://68kmla.org/forums/index.php?/topic/17191-mac-classic-pram-battery-carnage/

 

[Schmoburger]

Well I dont want to look like I am praying on the poor souls with damaged boards, but I have a stack (literally) of Classic One boards that are in great shape. No Classic II boards though. I can send them to Uniserver for a re-cap and he can ship to you if that is something you want. I am sorta working on other projects, but it would not take me much to test them and find a good one. If you want one direct from me, we can do that too. Just not sure if you have re-cap experience and they always need it.

We must discuss this at some stage soon, my friend!

 

[MacFanClassic]

Hello, I could make photos of the board. But too many components are broken and the board has many internconnects are are busted. I wanted to look for a different solution. Like adding an...that might sound like blasphemy now... Atari ST Motherboard.(In ST High mode)