Amiga 4000 Repaired!

johntayloruk · 23 June 2020, 19:25

Hey, just thought I'd do a post for a project I've been working on thanks to having lots of time with the lockdown.
I bought a non-working Amiga 4000 Motherboard on ebay, it was filthy, corrosion on many of the resistors, the battery had gone to work and had eaten its way through to the rear. I didn't want to even turn it on in the state it was is so I gave it a clean with white vinegar and IPA (my word the amount of fizzing and fishy smell...yuk ).

Anyway, I've had an ultrasonic bath I've been wanting to try for a while so I removed the caps and socketed chips and gave it a good soak. It came up like new and I could then see what I was faced with...

U177 (74HCT174) had pretty much been eaten away, hardly any pads remained and there were traces broken all over the place., particularly around the memory sockets going through the vias to the underside of the board.

The traces from the row of resistors around R982 to the jumpers at J975 were completely broken and had to be repaired.

The F245 chip at U891 had also been damaged and had to be replaced. Again that fishy smell when you get underneath...yuk!

Anyway....after many hours testing traces, re-flowing most of the board, replacing the caps and adding new simm sockets I turned it on and.....it only worked! I was so happy to see that WB 3.1.4 screen/ I did a full check with Chucky's Diagrom and all was ok. I used some solder mask to cover things and to secure some of the connections in place (probably too much), but it's working fine now!

I've had 10 of Chucky's A3660 boards made up so my next job is to put one together and then likely look to sell this as I have another original A4000 as well as a new one I've just made up!

Attaching some pics.

coldacid · 23 June 2020, 19:43

By IPA, do you mean India pale ale? (I'm seriously asking; I am not at all a hardware person.) Great fixup, though!

johntayloruk · 23 June 2020, 19:45

Haha thanks. Believe me I’ve drunk plenty of that over the last few months. IPA in this context is IsoPropyl Alcohol. Great for cleaning up all the gunk and crap on a PCB.

LucasBox · 23 June 2020, 20:02

Great work! I have a damaged board too, but Unfortunately I have no soldering skills.

johntayloruk · 23 June 2020, 22:28

You should reach out to some of the guys on here and get them to look at it for you. Some really talented people and I'm sure they would be able to look at it. Though I guess it will depend on how 'damaged' your board is.

Quote:

Originally Posted by LucasBox

Great work! I have a damaged board too, but Unfortunately I have no soldering skills.

23 June 2020, 19:25	#1
johntayloruk Registered User Join Date: Apr 2020 Location: Huddersfield Posts: 33	Amiga 4000 Repaired! Hey, just thought I'd do a post for a project I've been working on thanks to having lots of time with the lockdown. I bought a non-working Amiga 4000 Motherboard on ebay, it was filthy, corrosion on many of the resistors, the battery had gone to work and had eaten its way through to the rear. I didn't want to even turn it on in the state it was is so I gave it a clean with white vinegar and IPA (my word the amount of fizzing and fishy smell...yuk ). Anyway, I've had an ultrasonic bath I've been wanting to try for a while so I removed the caps and socketed chips and gave it a good soak. It came up like new and I could then see what I was faced with... U177 (74HCT174) had pretty much been eaten away, hardly any pads remained and there were traces broken all over the place., particularly around the memory sockets going through the vias to the underside of the board. The traces from the row of resistors around R982 to the jumpers at J975 were completely broken and had to be repaired. The F245 chip at U891 had also been damaged and had to be replaced. Again that fishy smell when you get underneath...yuk! Anyway....after many hours testing traces, re-flowing most of the board, replacing the caps and adding new simm sockets I turned it on and.....it only worked! I was so happy to see that WB 3.1.4 screen/ I did a full check with Chucky's Diagrom and all was ok. I used some solder mask to cover things and to secure some of the connections in place (probably too much), but it's working fine now! I've had 10 of Chucky's A3660 boards made up so my next job is to put one together and then likely look to sell this as I have another original A4000 as well as a new one I've just made up! Attaching some pics. Attached Thumbnails

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23 June 2020, 19:43	#2
coldacid WinUAE 4000/40, V4SA Join Date: Apr 2020 Location: East of Oshawa Posts: 538	By IPA, do you mean India pale ale? (I'm seriously asking; I am not at all a hardware person.) Great fixup, though!

23 June 2020, 19:45	#3
johntayloruk Registered User Join Date: Apr 2020 Location: Huddersfield Posts: 33	Haha thanks. Believe me I’ve drunk plenty of that over the last few months. IPA in this context is IsoPropyl Alcohol. Great for cleaning up all the gunk and crap on a PCB.

23 June 2020, 20:02	#4
LucasBox Registered User Join Date: Feb 2020 Location: Ger Posts: 35	Great work! I have a damaged board too, but Unfortunately I have no soldering skills.

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