A3000 leaking battery

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KarateEd
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A3000 leaking battery

Post by KarateEd » Thu Feb 13, 2020 5:29 pm

Hi Folks,

So my A3000 arrived yesterday and looked pretty nice. The pictures on the eBay site showed almost everything inside but I wasn't sure where the battery was on this thing. I took a chance that the board was good because the rest looked pretty pristine.....ha, never believe it if you don't see the battery area.

Anyway when I opened her up, I found the 'green gunk'. It had spread to the 4 OS ROMs but not much further. I cleaned it with vinegar and then with some filtered water (didn't have distilled on hand). It is just a cursory job until I can spend more time on it.

First question. Not all the green has gone out of the sockets on the board. Is it likely I will have to replace the sockets or is there a method you can use to get all the contacts clean. This problem is also in one of the keyboard sockets. One socket cleaned up ok (keyboard) but not the other keyboard socket.

Second question. The ROMs that were in the sockets were 2 pins short of the full length of the socket. Is that even possible it could be the correct chips in there?

I only have my phone camera and it doesn't always focus very well but I've added a couple of pictures of it.

Thanks guys and gals,
Battery and area.jpg
How it first looked
OS ROMs2.jpg
ROMs 1 and 2
OS ROMs.jpg
ROMs 3 and 4
After a cursory clean.jpg
Sorry about the focus, think I'll have to buy a decent camera.
Last edited by KarateEd on Fri Feb 14, 2020 6:20 am, edited 1 time in total.
Ed...... :-)

3 working Beebs, 1 RetroClinic Master, 1 normal Master, 1 A3010, 1 Pi2 RISC OS, 2 broken Beeb Motherboards, 1 Omnibus A7000+ server, 1 A7000+ Desktop, 1 PET, 1 C64, 1 C128, 1 Amiga 500 and 1 Roamer.

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Re: A3000 leaking battery111111

Post by Kazzie » Thu Feb 13, 2020 5:53 pm

Looks like you've got a real project going on there! :D

Sod's law says the one photo that's completely out-of-focus is the "after" one, so I can only advice on the basis of the "before" pictures.

The short ROMs aren't a huge cause for concern: earlier versions of RISC OS were smaller, so could fit on smaller ROM chips that didn't need as many address lines. Some models that shipped with shorter sockets needed a carrier board to be upgraded to a newer OS version. I've not checked the chip serial numbers, but I reckon you've got a set of RISC OS 2 ROMs there.

For the amount of effort you'd need to get those ROM socket contacts clean, I'd be tempted to buy some brand new ones and replace them. It's likely you'd need to remove them to work on the tracks underneath them anyway!
BBC Model B 32k issue 7, Sidewise ROM board with 16K RAM
Archimedes 420/1 upgraded to 4MB RAM, ZIDEFS with 512MB CF card
Acorn System 1 home-made replica

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KarateEd
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Re: A3000 leaking battery

Post by KarateEd » Thu Feb 13, 2020 6:35 pm

Thanks for this Kazzie.

I'll look into getting replacement sockets. I'm sure there's more to clean up on this board, I'll have to do a very careful inspection and trace out tracks to ensure continuity throughout this area. It looks like the gunk didn't go past ROM1 so that's good.

I'll also do the IPA cleanup once I'm certain there is no more green gunk anywhere. The sockets will have to be removed to ensure that's the case I suppose.
Last edited by KarateEd on Fri Feb 14, 2020 6:21 am, edited 1 time in total.
Ed...... :-)

3 working Beebs, 1 RetroClinic Master, 1 normal Master, 1 A3010, 1 Pi2 RISC OS, 2 broken Beeb Motherboards, 1 Omnibus A7000+ server, 1 A7000+ Desktop, 1 PET, 1 C64, 1 C128, 1 Amiga 500 and 1 Roamer.

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Re: A3000 leaking battery111111

Post by Kazzie » Thu Feb 13, 2020 9:59 pm

I'm sure you'll do just fine. Remember to download a copy of the circuit diagram (technical drawings) for the A3000 from Chris' Acorns to help you play dot-to-dot. :)
BBC Model B 32k issue 7, Sidewise ROM board with 16K RAM
Archimedes 420/1 upgraded to 4MB RAM, ZIDEFS with 512MB CF card
Acorn System 1 home-made replica

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richardtoohey
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Re: A3000 leaking battery111111

Post by richardtoohey » Thu Feb 13, 2020 11:26 pm

Good luck ... I've got a few A3000 corpses lying around ... beyond my skills (certainly beyond my procrastination levels!)

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KarateEd
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Re: A3000 leaking battery

Post by KarateEd » Fri Feb 14, 2020 2:56 am

richardtoohey wrote:
Thu Feb 13, 2020 11:26 pm
Good luck ... I've got a few A3000 corpses lying around ... beyond my skills (certainly beyond my procrastination levels!)
Hey Richard, so glad to hear from you. I know the procrastination one. I don't think there is much serious damage to this board and I've done a quick vinegar/water clean for a temporary measure until I can get work in earnest on this. Btw, who is this earnest guy?

I'm sure I'll learn something and it will be fun.
Ed...... :-)

3 working Beebs, 1 RetroClinic Master, 1 normal Master, 1 A3010, 1 Pi2 RISC OS, 2 broken Beeb Motherboards, 1 Omnibus A7000+ server, 1 A7000+ Desktop, 1 PET, 1 C64, 1 C128, 1 Amiga 500 and 1 Roamer.

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KarateEd
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Re: A3000 leaking battery

Post by KarateEd » Fri Feb 14, 2020 10:20 pm

Hey Richard,

Don't you have someone around there that could help you revive your A3000s?
Ed...... :-)

3 working Beebs, 1 RetroClinic Master, 1 normal Master, 1 A3010, 1 Pi2 RISC OS, 2 broken Beeb Motherboards, 1 Omnibus A7000+ server, 1 A7000+ Desktop, 1 PET, 1 C64, 1 C128, 1 Amiga 500 and 1 Roamer.

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Re: A3000 leaking battery

Post by 1024MAK » Sat Feb 15, 2020 1:32 pm

The green colour is known as Verdigris. It occurs when copper or an alloy made with copper (brass) corrodes. Just like you get brown rust when steel corrodes.

The distilled vinegar is used to neutralise the alkaline leakage from the cell / battery. The water is to clean off the vinegar and to clean off any other crud. The board must be throughly washed with water, as any residual alkaline leakage or vinegar can continue to damage the metals used on the board.

IPA is best for cleaning oils, grease, some types of flux and other similar substances. For general dirt, a soap/water mix can be used. Always wash off with clean water. If you live in a hard water area use demineralised or distilled water for the final wash (otherwise you risk limescale where trapped water droplets get trapped). If you use IPA, do this after the soap/clean water stage when the board is dry.

The main way of removing surface level Verdigris is physical cleaning using a toothbrush or by scraping using a blunt flat bladed screwdriver or similar. Once the worst is removed, for contact areas, a glass fibre cleaning “pencil” can be used. But these are no good for DIP/SIP sockets.

If the corrosion (Verdigris) is too bad, then whatever copper/brass is left will break away during cleaning, hence broken PCB tracks or weakened / broken socket contacts.

If something (socket / component) is damaged too much, the only practical solution is to remove it and fit a new one. But be careful, as solder that has been attacked by alkaline leakage from the cell / battery is hard to melt. So use flux and scrape the surface of the solder joint. Applying extra ‘fresh’ solder can help the heat to flow from the iron to the joint.

Where PCB tracks have been affected, it’s a good idea to add some protection. I have a PCB lacquer pen. But these are very hard to find nowadays. It’s possible that a car body paint clear lacquer pen may work, but I have never tried this. Or you can buy an a can of PCB lacquer / conformal coating spray. Use thin card and masking tape to screen off areas (sockets) where you don’t want it to go.

Mark

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Re: A3000 leaking battery

Post by daveejhitchins » Sat Feb 15, 2020 6:00 pm

Google "Solder Mask Touch Up Pens" there are lots about!

Dave H :D
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Products: ARA II, ARA III, ABR, ATI, AP6, MGC, AP5 . . .
For a price list, contact me at: Retro Hardware AT dave ej hitchins DOT plus DOT com

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