Old A500+ issue..

[mastersetter]

Hi all, first post here. Long story short, old amiga user, back messing with my old machines. Escom a1200, works fine, old a500+ doesn't. When switched on, I get different colour screens. Initially I was getting red consistently, I read to try a different kickstart rom chip. Did that no change. Put the old back in and reseated a few other chips apart from agnus. I'm mostly getting a black screen now, although light blue and pink? aswell. The power led is flashing.
The battery did a little leak and there is signs of some damage but I didn't think it was too bad compared to some. Here are a few pics.










Board seems in good condition?
If I leave it running for a while, denise, agnus, the cpu are warm to touch, gary and the cia brothers are cold.
Anyone any ideas? I would like to get this old girl working again..

Thanks for any advice

*ps* sorry for the large photos.

[guest20923]

Hi all, first post here. Long story short, old amiga user, back messing with my old machines. Escom a1200, works fine, old a500+ doesn't. When switched on, I get different colour screens. Initially I was getting red consistently, I read to try a different kickstart rom chip. Did that no change. Put the old back in and reseated a few other chips apart from agnus. I'm mostly getting a black screen now, although light blue and pink? aswell. The power led is flashing.
The battery did a little leak and there is signs of some damage but I didn't think it was too bad compared to some. Here are a few pics.










Board seems in good condition?
If I leave it running for a while, denise, agnus, the cpu are warm to touch, gary and the cia brothers are cold.
Anyone any ideas? I would like to get this old girl working again..

Thanks for any advice

*ps* sorry for the large photos.

I had the same problem with my A500+. I tried all sorts of cleaning and testing trace conductivity, replacing chips etc. I ended up getting another motherboard (which had a CR2032 battery installed) and putting that in. My original board was an 8A and the replacement was an 8.1.
Your board actually looks worse than mine did and I had the 'coloured' screens too. The colours are the cpu and rom chips self testing on boot and giving an error.

[scuzzb494]

This is my recent battery removal. I tend not to over do on the messing with stuff to be honest. You have to kinda work with one thing at a time. So I tend to go for power, main processor and gently reseat chips one at a time. Also leave running as you have and then do a soft reboot over and over. Try another power supply and also disconnect the floppy and maybe hitch up an external floppy and check the power to the floppy. In the first instance it really is a case of seeing actually if the blood is running round the system.

Not much help. Impossible to diagnose exactly what has fractured. But as kit gets older you run the risk of damaging even more by taking the kit apart. Like I say start small with one thing and then work your way around. Could be anything... even the keyboard. I just watch the patient from my small moves and leave big spaces between what I do and also listen for odd things.

http://www.scuzzscink.com/amiga/scuzzblog_october17_5/car_sbd_231017_109.jpg

http://www.scuzzscink.com/amiga/scuzzblog_october17/scuzzblogdoctober17_2303.htm

Sadly you have to catch the 500plus early as it can be quite destructive. Also overcleaning can be a bit toxic sadly. Clean up and neautralise the battery cleaning process. Always allow the board to dry.

This killed a 500 that I once had. I get the things out as soon as I can to be honest.

http://www.scuzzscink.com/amiga/scuzzblog/car_may16_04.jpg

This'll make you giggle. I swapped the 500Plus for a 500 mobo cus in truth it never really matters to me.

Good luck. Fun times.

[Motormouth]

I suggest sending it to Acill,  if he is willing to look at it.

Check out Acill's repair thread

[mastersetter]

Thanks all. I have a new gary chip in the post, will try that and see how it goes

[TCMSLP]

The very first image appears to show broken traces - including possibly ground?

[guest20923]

This link might be useful:
http://www.amigahistory.plus.com/selftest.html

[mastersetter]

Thanks, see that's the thing i'm confused about, im getting different colours on the boot than are in that list, it shows pink quite a lot ?! As for traces, maybe they are broken, the copper is discoloured due to the leak, hard to see really?

[guest20923]

No problem. It may not be the chips' at all, as shorted traces can cause the same thing apparently. The motherboard is multi-layered and there are soldered "through holes" near the battery area that acid can eat out and short. I don't know how to check it but I've heard it is a common complaint with battery leakage. If you have any isopropyl alcohol, it's a good cleaner. Also vinegar on a cotton wool bud to neutralise battery acid damage. Over time the acid can fume and spread further over the board causing corrosion on chips and joints. With cleaning you can also use a wire "toothbrush" for stubborn amalgamations.

[Acill]

I've got one sitting here that does the same thing. Its cost prohibitive to work on them when they are this bad. Its not worth the time or the money over just finding another one that works.

I dont have the time to repair so many traces for the chance it still may not work even after that. The last 4000 I did in similar condition ended up costing me money to fix for someone!

[mastersetter]

Thanks guys, I will try the chip and if nothing works then I will forget it, not worth the hassle and certainly not worth the money

[mastersetter]

Update, the gary chip had no effect. Thought about stashing this thing but I think I will have a go at a repair myself. Borrowed a multimeter, and using the pcb explorer (incredible) I have done some minor checking on traces around the leaked area. All of the ones that look bad are in fact fine, I get continuity through all of them, I could only find 2 that didn't work for me. One goes under one of the chips (74LS244N) and the other goes from a hole underneath a component and down to one of the pins on the expansion slot. Any idea why there is no solder in this hole? There are a few dotted around the board that I can see. I have treated and cleaned the area. Just waiting on my wire traces to appear in the post, and I will try and patch these two. Also the ground trace is fine.



You can see the clear hole underneath the lower leg of the upper yellow component here..

[scuzzb494]

Hi

You saved my life tonight.. well the life of an A500Plus. I grabbed one of my computers and set the camera up to take some pics of the motherboard for you to check those holes. Anyway when I opened the machine up I not only found a battery on the main motherboard but also on an A501 RAM board in the machine.

http://www.scuzzscink.com/amiga/scuzzblog_november17/scuzzblogdnovember17_0502.htm

So a big thanks for that. I think I saved the computer. I will find out tomorrow. The above links to all the images of the battery removal. Includes also those areas where you have holes but my board does not. Maybe it helps. Not sure.

Many thanks

[mastersetter]

Thankyou Scuzzb, that is a help, im sure it's prob a through hole that was missed when it went through the wave, as many are filled. I may fill it when I put in the patch wire. Another question, are the chips replaceable? I can find them online, 74LS244N, so can I just swap one out for a new one?
 
 Glad you managed to get the battery off, hope the board is ok

[scuzzb494]

Thankyou Scuzzb, that is a help, im sure it's prob a through hole that was missed when it went through the wave, as many are filled. I may fill it when I put in the patch wire. Another question, are the chips replaceable? I can find them online, 74LS244N, so can I just swap one out for a new one?
 
 Glad you managed to get the battery off, hope the board is ok

I am not sure whether you can desolder the fixed chips and replace in truth. I am sure someone else here could advise on that. I wouldn't have thought it was a problem though for me I would be swapping out the motherboard because you are hoping to fix a problem that may in truth just expose another. I have spent way too much time trying to get busted kit working just to find its a hopeless case. Saying that I tend not to give up and do come back to problems over and over.

Keep a search open on Ebay and watch for old 500s [ busted and broken ] to appear and snaffle what you can for as cheap as you can. Having spares is always very useful.

Your photography and cleaning processes are excellent. I trust you are going to try an make a log of your efforts and create a little web page for it. That way others can learn from your experience.

Matters not in the end whether you are successful or not in truth as long as you enjoy yourself. Getting the Amiga working again would be a real bonus. So I hope you are successful. Don't give up.. but maybe do some sideways thinking [ get some spares ]