A5000 - diving in at the deep end!

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rubber_jonnie
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A5000 - diving in at the deep end!

Post by rubber_jonnie »

So, here begins the A5000 repair thread, as promised!

At present the machine doesn't boot, however there is clear damage on the area of the battery, and having removed the RTC (IC58), there were some rather immediate problems apparent from the get go.

The clock oscillator circuit has a missing SMD cap, and from a circuit PoV, there are some definite missing connections. (More on that later)

It was also clear that the PLCC socket was heavily corroded, so given some of the nearby tracks were damaged, i decided it had to go. This is part way through the cleanup and you can see how bad the corrosion is on the pins:

PXL_20220522_145856910.jpg
PXL_20220522_145856910.jpg (463.45 KiB) Viewed 623 times

It also gives a good view of the clock oscillator circuit damage.

All the pins came out just fine:

PXL_20220522_150627091.jpg
PXL_20220522_150627091.jpg (385.87 KiB) Viewed 623 times

And you can see here the level of corrosion in this selection:

PXL_20220522_150618390.jpg
PXL_20220522_150618390.jpg (330.81 KiB) Viewed 623 times

Though you might have to zoom in!!

I've found a lot of missing connections now the area is clear, but nothing I feel that can't be fixed with some bodge wiring, though I am going to have to break out the finest wire I can find!!

The one thing that strikes me with this machine is how fine the tracks are. They really are super fine and very susceptible to damage by a leaky battery, and I think I got lucky here in that the damage is not as bad as it could have been. Damage is marked with black dots:

PXL_20220522_155822642.jpg
PXL_20220522_155822642.jpg (434.71 KiB) Viewed 623 times

So first order of the day, get the tracks repaired so we can see what it does, then take it from there. One thing at a time.
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
stephen_usher
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Re: A5000 - diving in at the deep end!

Post by stephen_usher »

That's not the worst A5000 battery damage I've seen. Relatively "minor" in the scheme of things.
Intro retro computers since before they were retro...
ZX81->Spectrum->Memotech MTX->Sinclair QL->520STM->BBC Micro->TT030->PCs & Sun Workstations.
Added code to the MiNT kernel (still there the last time I checked) + put together MiNTOS.
Collection now with added Macs, Amigas, Suns and Acorns.
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Re: A5000 - diving in at the deep end!

Post by rubber_jonnie »

stephen_usher wrote: Sun May 22, 2022 6:55 pm That's not the worst A5000 battery damage I've seen. Relatively "minor" in the scheme of things.
Honestly, I'm counting myself lucky.
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
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PhilC
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Re: A5000 - diving in at the deep end!

Post by PhilC »

Good luck with the repair @rubber_jonnie , there’s much more than the black dots to repair when you zoom in.

Still all repairable with some patience and lots of bodge wires
If it ain't broke, test it to Destruction.
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mrbombermillzy
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Re: A5000 - diving in at the deep end!

Post by mrbombermillzy »

Sorry for arriving late to this thread (had a real life emergency x2!).

Anyhow, as far as I can remember what happened with this...

The machine booted to the 'No OS' prompt when I originally purchased. However, on opening up, I noticed the battery had just started its 'ooze of death' routine, so I set to work on neutralising the threat (removing the cell and cleaning as much of the corrosive alkaline as I could get to).

I remember it being worst hit around the battery and wiping off a SMT component around there on the clean up. :(

Hopefully, its not too bad to sort and @rubber_jonnie can get this running again. :)

As for the mouse ball...I have no idea where to start with that! :o
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Re: A5000 - diving in at the deep end!

Post by rubber_jonnie »

PhilC wrote: Sun May 22, 2022 7:26 pm Good luck with the repair @rubber_jonnie , there’s much more than the black dots to repair when you zoom in.

Still all repairable with some patience and lots of bodge wires
Everything marked is basically an indicator of something that should be connected, but isn't. I can't help but think if the tracks had been a smidge wider they'd have been fine after a clean up, but I have buzzed everything out that looks damaged and have a reasonable map of what's bad, including the pads under and around the RTC clock and its oscillator circuit.

There are some tracks that look bad i.e. have a dark spot on them, but in reality once cleaned up, it's just uneven lacquer.

It isn't as bad as I have seen, all you need is one look at the results of a Maxell bomb going off in a Mac and you realise it's not that bad.
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
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Re: A5000 - diving in at the deep end!

Post by rubber_jonnie »

mrbombermillzy wrote: Sun May 22, 2022 8:53 pm
As for the mouse ball...I have no idea where to start with that! :o
This is totally new for me, I have never seen a mouse ball turn into toffee before!!!
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
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Re: A5000 - diving in at the deep end!

Post by alexh »

Enjoyable read. Good luck.
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A500+,A600,A4000/060,CD32,CDTV
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Re: A5000 - diving in at the deep end!

Post by rubber_jonnie »

alexh wrote: Mon May 23, 2022 12:27 am Enjoyable read. Good luck.
Thanks :)
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
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Re: A5000 - diving in at the deep end!

Post by alexh »

Mine didn't look too bad when I first opened the case but when I started to clean it, tip-toe gently, simply applying the white vinegar (I just poured a little bit out of the bottle) washed away C154, C159 and R430 and their pads :-(
Principal ASIC Engineer - SystemVerilog, VHDL
Thalion Webshrine - http://thalion.atari.org
STfm,STe,MegaSTe,Falcon060
A500+,A600,A4000/060,CD32,CDTV
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