Amiga 4000 Board Repair

mwkenna

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Hi Guys

After being told I'm not allowed to sell my A4000 I've decided to try and restore it to best condition. As indicated by several people on the for sale thread, it looks like the battery has leaked in the past causing a "greening" of the board. Also it looks like the PCB laquer has been corroded somewhat, I believe all the PCB traces are intact but I think it would be really nice to remove all the greening from the various component legs and re-laquer the board.
After doing some more reading it also seems to have suffered a capacitor problem in the past as the "audio capacitors" have been replaces with "chunkier" versions.

Can someone with more electronics experience offer some guidance - if it has to be sent away for all this to happen then so-be-it.

Thanks guys,
Mark.
 

abraXXious

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Hi there,

if you have not had much experience desoldering and reinstalling SMD caps (surface mounted as in the ones on an A4000) then I would strongly suggest you send it away for refurbishment. If you attempt it and dont have a steady/experienced hand then you will end up having to send it away, but it will cost more, or you could do some serious damage.

Im sure there are guys in the UK who do this. If you were in Oz I would recommend Nathan at AmigaManiac - he does this, checks the whole board and even recoats with pcb sealer when finished, and he is very well priced.

Good luck.
 

JLPedro

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First thing to do would use some Isopropilc Alcohol to clean all the green stuff out of the components and then to neutralize the battery acid most guys here would recommend to use lemon juice or vinegar (leave it some time on the pcb) and then clean all again.
 

mwkenna

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I do have experience in SMD repair but dont have the tools anymore. I think I would like to give it a go myself as it seems like a challenge! If I mess it up I can always send it off.

If anyone knows who the best suited person is in the UK to do this sort of thing then please let me know.

Cheers,
Mark.
 

davideo

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Amigakit offer some repairs to Miggys. It may be worthwhile contacting them (y)

You could also advertise on here for a new motherboard.

I did that and did a swap for my old board for a refurbished motherboard (y) with part payment. It worked out to be more cost effective than sending the old board to New Zealand or Australia.

But whatever you decide you need to remove the battery and clean any gunk of the board before it's too late.

Dave G :cool:
 

AndyLandy

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Anthony Hoffman in NZ is an Amiga 4000 expert, his webpage is here: http://amiga.serveftp.net/hardware_repair.html

Alternatively, you could PM 'hikey' on this forum. He is also well-versed in the art of A4000 restoration and might be able to do you a part-exchange for a new, working board.

Good luck!
 

davideo

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@Andy

Apparently Anthonys going to be out of touch until late next year (n)

He's in the Antartic of all places. He's set a link on his website to his blog with the intention of keeping it updated on his expedition.

I wonder if he took his Miggy with him?

Dave G :cool:
 

Zetr0

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@mwkenna

Okay... heres what can be done

1. you need to neutralize the battery alkali

you can use any acetic acid, like spirit vinigar or lemon juice - be liberal and use an electric tooth brush.

dont push hard on the toothbrush let the oscillation action do the work

This effort will also remove any remaining the potassum hydroxide and potassium peroxide - it will also break down the copper thats oxidized to copper hydroxide (those little blue/green bunnies)


2. Deep Cleaning

This can be achieved in a couple of ways but if you have a dish washer then I suggest the following.

A "quick" (30 minute) wash on 60c - stop the process before the drying cycle - I use a splash of washin up liquid on the board - dont go crazy or you will have foam seeping from the dish washer seals... (trust me... the wife like to tell me off for that lol)

once the board is washed - put it though a cold rinse if you need to - and then put up on a high shelf in an airing cupboard for atleast 36 hours... on its side with the IO ports at the bottom - you can rotate this after a day if you remember.

Once 36-42 hours is up - it will be completely dry for the next part of the process - which is repair.


3. Repairing the Board.

Now the area most effected is the RAM Latching F245, the 47uf feed caps and the 74LS174 ic next to the battery - its wize to get hold of a multi-meter and check all the tracks for continuity.

to remove components of this nature you will need hot air - or if you are skilled use solder-wick / braid. However I personally beleive one would have to be a demi-god to pull the F245 from the board with just solder-wick!

I suggest that you contact Amiga Kit - FOL is a very skill technician and I personally rate his work very highly, there exists some semi professionals in the UK that could solve this issue for you for not much.

Personally I would love to help - alas I dont have the time at the moment, if you are still struggling to find assitence in about 4 weeks time though, hit me up on PM and we can sort somthing out.

but what ever you do, do not delay Step 1 and 2, try and get them done as soon as possible.


good luck on your quest =)
 

mwkenna

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Thank you - that was most helpful. I think I am going to try to remove the components myself using hot air rework station.

I have some extensive experience in SMD soldering although none in hot air soldering. I will experiment on some dead bords first. I was thinking of removing all components from the board, ultra-sonic cleaning it and then re-laquering before cleaning all the components and re-attaching.

Anyone have any experience with ultra-sonic cleaners?

Cheers,
Mark.
 

mwkenna

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I have also noticed that sometimes when the machine is booted the keyboard caps-lock light just blinks on and off and the keyboard does not work. Unplugging it and plugging it back in causes the machine to reboot - any ideas on that one?

Cheers,
Mark.
 

davideo

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I have also noticed that sometimes when the machine is booted the keyboard caps-lock light just blinks on and off and the keyboard does not work. Unplugging it and plugging it back in causes the machine to reboot - any ideas on that one?

Cheers,
Mark.

Mark

The caps-lock flashing is a code. You need to take note of the pattern and visit the site that Andy posted earlier http://amiga.serveftp.net/hardware_repair.html to see what your code means.

You'll find lots of usefull stuff on there including tips, tricks, manuals, etc.

It's well worth a look around.

Dave G :cool:
 

mwkenna

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May just be me but I can't find anything about keyboard codes on that site (lots of other goodies on there though!). Can you paste a direct link please?

Also, because some of the PCB laquer has been dissolved (tracks are fine) I would like to re-laquer the board - is this possible:

1) Remove all components
2) Strip the laquer/solder resist
3) Re-laquer
4) Re-attach all components

I know the obvious thing is the amount of effort/time but i have lots of patience and determination.

Cheers,
Mark.
 
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davideo

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Mark,

I'm sure it's multilayered.

Dave G :cool:
 

mwkenna

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Ok, finally got around to getting the 4000 apart ready for the battery removal and board cleanup.

Here are the closeups - it looks like the battery is definately leaking, can you only get the coin batteries these days or would someone stock a "same style" lithium battery?

Cheers,
Mark
 

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davideo

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There are several options open to replacing the battery.

You can even buy an original battery, you can do the lith bat hack (search aminet) or as I did a rechargeable direct replacement coin cell battery.

The piccy is of my old board I traded with hikey - thanks hikey (y)

Dave G :cool:
 

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