Successful Repair of A3000 (Battery Removal)

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Julz
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Successful Repair of A3000 (Battery Removal)

Post by Julz »

Hello All,

I've got some good news today (at least it is for me). I've just got an A3000 I bought from eBay as 'spares / repairs' (ie. not working) fully working again!

I've already got a refurbished A3000 (bought from 4d Pi Shop on eBay), but it came with no accessories! So, I bought this one as it came with a working, if yellowed, monitor (AKF17), manuals, cables, magazines, cover discs, and some software titles. Also, it was a 'home' Archie - only one careful, previous owner, so no 'school' markings on the case (which still retains its 'cream' colour). I 'guess-timated' the total cost of the accessories, alone, if I were to sell them separately (looking them up of eBay), would come to more than what I'd bought them for, including the machine!

The original idea was: wait until the warranty has expired on the refurbished A3000, then swap out the case with the other one, (the refurbished one has 'school' markings on it, and is slightly yellowed), and sell the PCB off as 'spares', assuming the battery had done its damage, and it was as dead as the proverbial dodo. I had no intention on doing any soldering, or 'brain surgery', as I'm a complete numpty with that sort of thing!

I felt a little braver then I did opening up my Beeb (see thread re. cassette interface issue viewtopic.php?f=3&t=19789), partly because I'd assumed this machine was past saving, so I thought I'd have nothing to lose, by having a poke and a tinker with it. Only the case mattered.

After removing the case (carefully making sure to keep the plastic tabs intact), and giving the PCB a clean with a sprayduster aerosol, I couldn't see any obvious damage! So, after viewing a couple of YouTube videos, and looking on here, I decided to have a go at removing the battery. Once I'd done this, and cleaned around the battery area with cleaning alcohol, I still couldn't see any obvious damage. Examining the battery itself, I could see some brown 'rust' (ie. corrosion) around one side of the 'coin' part. Had I caught it in time?

Next day, I hooked it up to the monitor and switched on. Got the 'wavy / rolling text on a black screen' thing. Switched off, then on again holding down the reset button. Same thing. Switched off, then on again holding down the 'DELETE' key. IT WORKS!!! Boots into RISC OS 03 and it's got 2MB RAM. Tried loading a game ('Lemmings'). WORKS! Proof that, if *I* can de-solder the battery, ANYONE CAN! :D

So, now... I've got TWO working A3000s! All I need to do now is fit a new battery to it. However, is there a way I can do this so it is external? eg. run a couple of wires from the PCB to that 'little compartment' underneath the A3000? The one that looks, in fact, a lot like a battery compartment. (Was it ever used?)

I'd like to take the opportunity to say a BIG THANKS to those who posted on this site with the various info. that helped me perform this 'miracle'! :D
Kazzie
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Re: Successful Repair of A3000 (Battery Removal)

Post by Kazzie »

I've fitted a pair of AA batteries to an A3000 this past week (and I've got another to do next week). The machine really is designed for it: as well as the plastic compartment there's an unpopulated header (LK5) and holes to solder a diode in the corner of the board.

Have a look at this thread to see what I did. The battery contacts I used were from eBay; they needed a bit of trimming but it was easy to do with a pair of edge cutters.

(P.S. It's amazing how confident you get with a screwdriver when you're doing a last-ditch-repair :) )
BBC Model B 32K issue 7, Sidewise ROM board with 16K RAM
Archimedes 420/1 upgraded to 4MB RAM, ZIDEFS with 512MB CF card
RiscPC 600 under repair
Acorn System 1 home-made replica
Julz
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Re: Successful Repair of A3000 (Battery Removal)

Post by Julz »

Thanks, Kazzie.

I've had a quick look through your thread, and the battery damage I had on mine was nowhere near like the one on your example, as it was only a bit on one side of the battery, itself. So, I was *very* lucky to have caught it in time; even more so, when you consider I'd bought it as 'spares or repairs -not working'!

Re. your battery solution: that looks very neat, indeed, and I may give that a go, at some point. However, I was considering buying one of these: Varta V150H 3.6V NiMH Button Rechargeable Battery, 150mAh, and connecting that to the PCB, via a pair of wires,with some sort of connector in the middle, and house that in the battery compartment.
Kazzie
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Re: Successful Repair of A3000 (Battery Removal)

Post by Kazzie »

Julz wrote:
Sun Aug 09, 2020 8:17 pm
Thanks, Kazzie.

I've had a quick look through your thread, and the battery damage I had on mine was nowhere near like the one on your example, as it was only a bit on one side of the battery, itself. So, I was *very* lucky to have caught it in time; even more so, when you consider I'd bought it as 'spares or repairs -not working'!

Re. your battery solution: that looks very neat, indeed, and I may give that a go, at some point. However, I was considering buying one of these: Varta V150H 3.6V NiMH Button Rechargeable Battery, 150mAh, and connecting that to the PCB, via a pair of wires,with some sort of connector in the middle, and house that in the battery compartment.
That's a route that others have taken, and it has served them fine. I was drawn down the regular AA battery route because that's what my A420/1 used, and probably what was originally planned for that corner of the A3000's circuit board.

The other A3000 I'm repairing got away much better off: that just needs a fresh battery fitting (next week).

If you choose to use the LK5 connection with a rechargeable battery, you'll want to fit a wire link instead of the diode at D1.

By the way, did you remember to give your battery area a wash down with vinegar before the alcohol cleaning?
BBC Model B 32K issue 7, Sidewise ROM board with 16K RAM
Archimedes 420/1 upgraded to 4MB RAM, ZIDEFS with 512MB CF card
RiscPC 600 under repair
Acorn System 1 home-made replica
Julz
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Re: Successful Repair of A3000 (Battery Removal)

Post by Julz »

I've attached a photo of the area here:
20200809A3000BatteryRemoved.jpg
AFAIK: nothing got onto the board, itself, so I only applied the alcohol to clean off the sticky pad and dirt.. However, if you think it needs some vinegar on it, I'll go and do that.
Kazzie
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Re: Successful Repair of A3000 (Battery Removal)

Post by Kazzie »

The key thing that the vinegar will do is neutralise the alkaline goop that leaked from the battery (remember pH lessons at school? ;) ), so that it can't eat away at anything on the board instead. The alcohol is a solvent, so it works by disolving dirt and muck , to be wiped or poured off.

I don't know how efficient alcohol is at removing battery gunk on its own. If you haven't gotten rid of all of it, the remains will continue eating into the board, tracks, or components after you've put the lid back on and gone away.

I suggest you give it a dousing in vinegar, followed by another alcohol wash, for peace of mind if nothing else. After all, you'll need to get the board out again to fit the new battery, won't you? ;)

Leave the vinegar on the board for a minute or two, and agitate gently with a brush if you have one. It it's reacting with any battery alkaline, you'll see some tiny bubbles forming in the vinegar.
BBC Model B 32K issue 7, Sidewise ROM board with 16K RAM
Archimedes 420/1 upgraded to 4MB RAM, ZIDEFS with 512MB CF card
RiscPC 600 under repair
Acorn System 1 home-made replica
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gslug
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Re: Successful Repair of A3000 (Battery Removal)

Post by gslug »

The PCB itself looks fine, but some of the battery's contents seems to have found its way onto the inductors to the right (L11 to L14). I'd try to clean off that green corrosion on their legs.
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