Amiga hardware info, help and support with a focus (but not limited to) North American NTSC experiences. Open to all.
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New Orleans, LA, USA

by obitus1990 posted Thu May 30, 2019 7:00 pm

I managed to get my hands on a second A3000 for a decent price (if anything in Amigaland can be called that these days). It is a working system, but, has the dreaded Varta damage.

I’ll update this thread as I progress. I find it amazing just how far the battery’s contents can reach on this board. There is even green corrosion on the 25/16 MHz jumper, all the way on the other side of the board.


Battery removed and initial cleanup (a lot more will be done — including removal of ICs, solder mask, etc.):


More to come over the next few weeks as I have time...
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New Orleans, LA, USA

by obitus1990 posted Fri Jun 07, 2019 9:56 pm

So, I had a little time today to do some more work on the system. I had mentioned that there were distant spots of corrosion, nowhere near the battery in the prior post. Well, come to find out, it wasn't from the battery. Evidently, a mouse had gotten inside this computer, thanks to the prior owner not replacing one of the expansion bay covers, and proceeded to crap and piss on random spots on the motherboard. Disgusting. I found few mouse turds scattered around the motherboard. So, it got a total washdown with isopropyl alcohol today.

I had to remove a dozen of the EMI filters on the SCSI and parallel ports to address the corrosion the vermin had caused.

I made a catalog of all the required parts to replace corroded components, and, ordered them from Mouser today. Next time I update, I will have been in ground-plane hell desoldering all of these passives and ICs damaged by the battery. I have a love/hate relationship with the A3000 due to how hard it is to desolder and resolder components due to the very large copper ground planes it has.

After component removal, I can sand the damaged solder mask and clean up the copper underneath, then recoat with some UV cured soldermask repair material.

One thing I'd like to mention is that if you are treating a battery damaged Amiga, make sure you flip the board over and check the vias on the other side of the board, near the battery area. I found six of them with corrosion from the Varta death fluid leaking through them.
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New Orleans, LA, USA

by obitus1990 posted Tue Jun 11, 2019 6:26 pm

Cleanup continues...removed a few ICs, discovered a broken trace (will be repaired after all is cleaned up), and found that several lands on the plated through holes had been corroded away completely on the component side. The solder side lands and the through holes themselves are still intact, though.





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Springfield, MO

by EzdineG posted Tue Jun 11, 2019 7:10 pm

Great work! Looks almost new ;)
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New Orleans, LA, USA

by obitus1990 posted Tue Jun 11, 2019 7:34 pm

EzdineG wrote:Great work! Looks almost new ;)

Thanks...she's getting there. There's just not enough time in the day, though :)
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Roseville, CA

by Mr.Toast posted Tue Jun 11, 2019 7:42 pm

Yes that is awesome! So much filth with a rodent multiplier :/

I recently did a total submersion approach on a board that was in good working order with nearly zero battery damage. Large but shallow storage box, 5-6 bottles of standard 91% alcohol and a few brushes did the trick. The alcohol pooling up was NASTY. But the end result was a mostly clean board that just needed some spot treatments with Q-tips.

I need to find a friend with a large ultrasonic cleaner. Those things are just too expensive at the scale of work we're doing.

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by Crazyeights posted Wed Jun 12, 2019 8:29 pm

I put a nasty old A500 motherboard in the dishwasher years ago and it came out great! I did let it dry for a few days before putting it back together. It still works! I wouldn't try that with my A3000T though :D

Congrats on the A3000 project!
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New Orleans, LA, USA

by obitus1990 posted Fri Jun 14, 2019 5:57 pm

FINISHED up the battery section. I replaced every single passive (cap, diode, ferrite and resistor, and trimmer cap) in the area that had signs of corrosion. Then out came the three small ICs, which were replaced with brand new ones. Next, I removed the sockets for denise and paula and replaced them. I laid on some solder mask replacement (a little to thick in a few spots), repaired a busted trace, then installed a coin cell holder with anti-charge diode. The result is a fully functioning amiga 3000. Now I just have to replace the EMI filters I removed due to mouse piss corrosion.




IMG_7649 2.JPG

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by McTrinsic posted Fri Jun 14, 2019 11:37 pm


I guess the MPC - term will be my word of the year ...


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