exxos's Atari, Amiga & retro forum

As promised to some members of the forum, here's a new thread about my Acorn A5000 journey.

Let's start with some pictures:


The board looks nice, but 3 chips are missing: two 74HCT245T and the RTC chip. I will have to test continuity on some tracks though.


Two bodge wires are soldered at the back of the motherboard, due probably to bad tracks.


The missing RTC chip, and a missing pad to add more fun to the repair... Sorry for the blurry pic :oops:


Two missing 74HCT245T (and also a missing pad).

The PSU was clogged with dust and it took me a lot of time to get rid of all that dirt. Yurk ! :shite:


The top lid was looking better...


And the final result. Still some dust here and there, but I will clean it thoroughly when I replace the actual fan with a silent model.


I have already received the two missing 74HCT245T but I am still waiting for the RTC chip, the keyboard and the mouse.

Stay tuned !

Nice. Good luck.

As an A5000 alpha owner (which I bought dead) I've been reading lots of A5000 resurrection threads. People recommend removing the IDE and FDC connectors to check underneath for battery damage and / or rot that has not been neutralised.

Interesting motherboard revision 192,105 normally 25MHz A5000's are 192,100 and 33MHz A5000s are 192,420.

Very nice.

Home computers got really complex very quickly in that decade. That PCB looks like alien technology compared to the ZX Spectrum 10 years before.

It's a pity Acorn weren't more successful - excluding the RISC cpu obviously :lol:

There's an A7000 on ebay at the moment - at a very reasonable price. They seem easier to obtain than Falcons/TTs for example. However they all seem to suffer with track damage so beyond my skills. I could add a bodge wire or two, but after seeing your seamless fixes it would make me feel 'bad' :D

One day...

chronicthehedgehog wrote: 20 Nov 2023 11:38 There's an A7000 on ebay at the moment - at a very reasonable price.

I was under the impression that A7000's are not greatly sought after as they are not quite RISC PCs (don't have VRAM or upgradeable CPU) and they are not quite Archimedes.

alexh wrote: 20 Nov 2023 11:45 I was under the impression that A7000's are not greatly sought after as they are not quite RISC PCs (don't have VRAM or upgradeable CPU) and they are not quite Archimedes.

That would explain it. I don't know much about them tbh. According to Wikipedia they were an entry level computer so that sounds right

EDIT

Tbh, my knowledge of the Archimedes could be summed up in one word: 'virus' :D

@alexh

I was thinking about removing the IDE and FDD connectors, but they seem clean as no rot is visible on the pins nor around them.

On the other hand, if a track is broken under the connectors, I will have to remove them for sure.

Will check concerning mobo revision, as I didn't know that.

@chronicthehedgehog

Never feel bad...

If you don't try and practice, you'll never start any repair.

:!:

I was also considering getting an Acorn A7000, but as @alexh resumed it, it's quite a "crossbred" machine.

Not very expandable, and the only plus is its CD-ROM drive.

Very nice, the battery damage is not too bad, at least visually.

I had to replace the RTC/Config IC and one of the 74HCT245s as well, so perhaps it's a known side effect of battery leakage. I definitely agree, you do need to continuity test everything to those 3 ICs as a minimum and just be aware that you can get corrosion failures down the line.

As for the IDE and floppy connectors, mine had bad corrosion on the pins and under the plastic shield, so I'd advise a very thorough review to see just how well they've held up.

It's definitely worth heeding what @alexh said about them.

As for the PSU I'd definitely check for leaky caps, mine smelled like a fish market as soon as I powered it on, and was ultimately very unstable. I suspect a combination of the electrolytic fluid, plus a very fibrous PCB that soaked up said fluid, and ensuing corrosion caused the PSU to need time to start up when loaded up. This was when I was using a real spinning HDD, so more load there too.

I've ended up replacing my PSU with a Meanwell one, the 5v is only able to deliver 4A rather than the 10A of the original, but I only have 2 installed podules and the hard drive is a BlueSCSI so ultimately power draw is pretty low and well within the PSU spec. My IDE drive is also solid state, a Transcend 128MB device, so low power draw there too.

@rubber_jonnie

Like for my A3000, I will for sure check whatever is necessary.

Capacitors in the PSU were all OK, and once the dust cleaned off, the fan got more silent.

Meanwell PSU is also a solution, but it would be only in case the original one fails.