Resurrecting A4000 rev 2

hese

Well-known member
AmiBayer
Joined
Aug 24, 2008
Posts
1,685
Country
Finland
Region
Savo
I received a battery leaked A4000D motherboard for repair and restoration. This time a bit more rare rev 2 motherboard. The previous owner had replaced the leaked barrel battery and done some repairs. The SIMM sockets had been replaced with vertical sockets and surface mount capacitors with through-hole parts. The board did not boot when it arrived here.


Several traces and pads around the battery area were repaired with jumper wires by the previous owner. Some fixes were quite subtle, some not so much. Three traces below the C192 capacitor were in a rough shape. And so were the three vias next to the outermost SIMM socket. The vias were fixed with jumper wires but the fix didn't work anymore as the traces were corroded too much to conduct. A few traces of the outermost SIMM sockets were repaired with jumper wires.


Some fixed were also done for the audio circuit. All surface mount capacitors had been replaced with through-hole parts. Some of the capacitor pads were loose and one was missing. The missing pad was fixed with a blue jumper wire.


The repair begun by removing all the SIMM sockets and surface mount components around the battery area. The traces under the SIMM sockets were in quite a bad shape. Well over 20 traces had begun to corrode, some of them were broken and some soon to be. Also quite a few pads, traces and vias near the battery area were either missing or corroded. Notice the amount of battery acid under the J975 connector :mrgreen:


The traces of the SIMM sockets were cleaned and then repaired with jumper wires. Also the three vias and traces on the left-hand side of U850 were fixed with longer jumper wires. Also the missing pads and traces around the battery area needed quite a few jumper wires (and hours). Jumper wires were okay for the missing pads but maybe for the next repair I'll make proper pads of copper sheet.


The through-hole capacitors were a bit annoying to replace as all of them were glued to the motherboard with epoxy. :?


The audio area was cleaned of capacitor leak. The through-hole capacitors were replaced with surface mount parts. Through-holes get the job done but I prefer to keep the original look of the board. The blue jumper wire was replaced with a thin wire that goes under the 1k resistor next to the C433 capacitor. The wire won't be noticed without a magnifying lens :p


There were also some other issues with the board such as broken ICs and traces but after taking care of them, the board was fully working again.


Till next time.
 
Last edited:
What's with the sour reception around here? You don't like the craftmanship?
 
Actually I'm following this thread. I have an a4000d mb that has 6 chips removed that I plan on try to resurrect. Plus battery damage. Just cleaned it up and am getting ready to buy parts for it. So I think what you did is awesome. I save the thread to be able to maybe ask you questions.

Sent from my SAMSUNG-SM-G900A using Tapatalk
 
Personally, it always makes me smile a little if something precious is brought back to working order rather than being allowed to languish in a non-working state, or worse, thrown away. Nice work sir, that's part of the reason I'm hanging around :)
 
Great work Hese! I'm working on a A4k with similar symptoms and also is working again ;) Long life to the A4k ;)
 
Nice work with the tracks and pads - how did you redo the tracks? Conductive pen then solder on top? Looks really good :)
 
Thanks, dalek. :)

The tracks were redone with thin copper wires only. In my opinion conductive pen/paint is more laborious and unreliable approach for fixing tracks as you need to mask the surrounding areas before applying the paint and may need to let it dry and apply a few times before the connection is good enough. I only have experience with conductive paint and wouldn't use it to fix tracks because the results were too flaky. And the paint gets scratched easily unless you coat it somehow.
 
Great work! I had a 4000 motherboard with a broken trace between the via and R79. I used a few coats of conductive paint, though. Seems to work okay.
 
Good to hear you got better results with the paint than me. Ages ago I fixed a battery leaked A500 with paint and it worked a couple of months till the fix didn't conduct anymore. I then redid the fix with copper wires and didn't have to get back to it anymore.
 
Thanks for the tips - really neat work there :) I have some A2000s motherboards and A501 expansions to repair - I think I'll try your method as it looks way more solid.
 
Hi,

I just bought a pristine A4000, and cleaned it up to the best of my abilities, however, leaky battery has corroded it badly.

I don't have the tools (and proper eyesight anymore) to go the route of removing surface mounted components, and recreating traces.

Would like a professional to fix it.

Please leave me a note and contact method.

Regards,
Bruno
 
If this is the quality of repair i can expect with my A4000 Motherboard, then i am happy to have sent you my board.
Brilliant craftmanship! Big thumbs up.
 
Last edited:
Back
Top Bottom