Another A500+ restoration project

[kipper2k]

Hi All,

Here is my next little project. This is one of the broken A500+ i bought on Ebay. I have no idea as to the extent of the

problems this board actually has. There are obviously quite a few visual problems that can be seen. Battery leakage has damaged

the board around the local area and corrosion has spread to the logic and Gary socket as well as some of the components. The

board at one time has had a partial cap replacement asthere are a couple of new electrolytic caps on the power input portion.

The Agnus socket has been damaged and needs to be replaced, the Joy and mouse port are really bad and they need to be replaced.

it kinda looks like the board has been stood on its right side at one point as there is a lot of damage on the board edge. It

would appear that it was probably stored outside in a shed at one time

So first things first, need to remove all chips, both 9 pin sockets, Agnus and Gary socket, clean it up and see just how bad it

looks under there. The expansion port pins are bad too, i will only replace them if the board actually fires up (not literally

I have ordered a few of each resistors, caps, sockets, IC's and various bits and pieces i need to hopefully restore it.

Here is a picture of the damaged area on the top of the board



There is a lot of green corrosion on pretty well every socket and logic chip so best to play safe and remove it. It also gives an

opportunity to take pictures to actually see all the traces under the components for future tracing etc.

Here is a link to a Hi-Res image


You can get a good look as to the damage of the Agnus socket, the pins are in really rough shape as it looks like someone fought

to remove the Agnus. This was the first socket to remove as i reckoned that if it was too damaged then this project could be a

non starter. Fortunately the socket pads look good so i continued on to remove the other components.



Here is a pic of the board after the bad areas have been cleaned up a little



and here is a supersized link at the board so you can see the detail.

I'll update as i get more things done, It will take a couple of days to get more parts so may take a bit.

[Lord Aga]

Hi Kipps Maybe this video will help you a bit. It is one of the best, if not the very best, Amiga restoration videos I have ever seen. And it's about A500+.

[ Show youtube player ]

[jimbob]

Yuck, I have one that looks just like that, bought from ebay too.

"One chip is broken, otherwise good condition"

The broken chip was the video hybrid. All I've done is remove the battery and replace the video hybrid with your replacement board. A quick test and there were no signs of life so it will have to be a full restoration like you are doing here. I'll be watching your efforts until I get a chance to work on mine. Good luck.

[kipper2k]

Originally Posted by Lord Aga

Hi Kipps Maybe this video will help you a bit. It is one of the best, if not the very best, Amiga restoration videos I have ever seen. And it's about A500+.

[ Show youtube player ]

Hi,

I seen that one a while back, its a good video, I don't have the patience to do all that work for videos, i like using photos, especially when you can use them for checking traces etc

[Lord Aga]

Yup, hi res photos are much better for details Whenever you make some, post 'em here

[kipper2k]

K,

I received the parts i need to start the check/rebuild portion. Before i am replacing the sockets i am actually checking the traces that run underneath them, so without further ado here is the first bad trace i found. Take a look at pin 4 (4th pin from the right on the top). The trace is no longer connected to the pad so i will run a jumper wire underneath the board later...

edit... add pin 1 as bad trace also at the pad, so 2 jumpers so far

edit 2, add pin 11, 12 and 16 to the list also. traces gone at the pads

[kipper2k]

k,

I resoldered all the removed components, added the jumpers for all the bad traces i had found and powered it up... Black screen... damn, i thought i was looking good.

Ok, next step was to take out my own a500+ connectivity charts that i created for checking continuity between the various components that could possibly be affected. First place to start the checks were all the trace lines coming from Gary.

next bad traces i found was...

Gary, Pin 11 > CPU pin 7 > Agnus 52 (no connection, trace bad)
Gary, Pin 43 > via resistor R101 > CPU pin 10 (no connection, trace bad).

Added the new jumpers to the board, turned it on and Up she boots . Tapped the board in a few places and jiggled the wires and no freezing etc.

Next step, resolder 2 new DB9 connectors, attach the floppy drive and boot up a game. so booted up the Addams Family plugged in audio and played the game fine with audio from both channels.

So next, i need to replace the expansion port connector to get rid of the bad corrosion on the pins and pads, and replace the DB25 connectors that also look a little sad.



Here is a picture of the repaired top of the board, sockets added for agnus, U10 - U13 and Gary. Replaced all the resistors and caps that i removed earlier




Here is a link to a Hi-Res image



Here is a pic of the bottom of the board showing the added jumper wires



and here is a supersized link at the board so you can see the detail.

I'll update as i get more things done, you'll probably see little bits of paper towel on the board used for wiping down, nothing to worry about

[Lord Aga]

Originally Posted by kipper2k

Added the new jumpers to the board, turned it on and Up she boots .

Woohoo, way to go Kipps
I just love these stories of successfully repaired/restored Amigas
Also, I love staring at those beautiful hi res pics

[kipper2k]

Here is a nice little pictorial guide of the main area where damage is located once a battery leaks. It may be spread further than this but this will give you a good idea as to where to start checking. I have highlighted the traces in yellow so you can see where the traces are going. You can use your meter to check continuity between the points shown.

This board actually looks in nice condition but there are 2 bad traces in this area that need to be fixed.




Here is a link to a Hi-Res image

[prowler]

Thankyou so much for this thread, Kipper!

I have an A500Plus in much the same sorry state as the first one you repaired above. I have to say that I thought it might have been a lost cause until I read your account of how you tackled that one.

I cut out the battery and killed all the corrosive spillage on the board when I first took it apart. I'm now encouraged to have a go at repairing it when I get the time, rather than just keeping it for spare parts.

[kipper2k]

Originally Posted by prowler

Thankyou so much for this thread, Kipper!

I have an A500Plus in much the same sorry state as the first one you repaired above. I have to say that I thought it might have been a lost cause until I read your account of how you tackled that one.

I cut out the battery and killed all the corrosive spillage on the board when I first took it apart. I'm now encouraged to have a go at repairing it when I get the time, rather than just keeping it for spare parts.

Nice to hear, If you need more close ups i can try to oblige for you

[GadgetUK]

Great work! I thought my 500+ had bad leakage but yours is insane - ouch at the expansion connector as well =O

[Dougal]

Your thread and pics are going to be super handy today. My A500 Plus died for me yesterday and I think this is why (See pic).

I had removed the battery years ago after it had leaked. Up until yesterday it was working fine with an Indivision ECS and a Kickstart switch. But after I added 1MB extra ram (trapdoor) it started crashing and guru'ing and got worse and worse within 1 hour to the point where it no longer boots.

I'm suspecting that adding the RAM was enough to finish off the damaged traces/tracks as even after removing the expansion etc it remained the same. (The 1MB expansion is fine & fully tested with another Plus)

Your pics and this thread will be super helpful for sure :thumbsup: