Done scratching that itch

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anightin
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Done scratching that itch

Post by anightin » Tue Nov 26, 2019 10:09 pm

I was busy building my System 3 keyboard, and generally minding my own business when I spotted Rob Taylor's A500++ board on an epoisode of RMC.

#-o

Lots of pocket money and a few weeks later the itch is now scratched:
IMG_5365.jpeg
Now, back to my 8 bit machines and builds :lol:

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Diminished
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Re: Done scratching that itch

Post by Diminished » Tue Nov 26, 2019 10:55 pm

What a beautiful soldermask.

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anightin
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Re: Done scratching that itch

Post by anightin » Tue Nov 26, 2019 11:06 pm

Diminished wrote:
Tue Nov 26, 2019 10:55 pm
What a beautiful soldermask.
I did a rebuild on my Norton Commando 750 in the 90's with a mate, I had the frame powder coated and all the casings polished -- we just sat there with a beer some evenings admiring the part built machine as one would a piece of art.

This truly was one of those moments, except now I'm on the G&T instead of Tennent's Super :D
IMG_5302.jpeg

Here is was in all it's un-blemished glory when it arrived!

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Diminished
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Re: Done scratching that itch

Post by Diminished » Tue Nov 26, 2019 11:14 pm

I don't know if you've used KiCAD, but its default 3D rendering of PCBs boasts a shocking pink soldermask with a pale blue silkscreen. I was rather disappointed when I realised that nowhere affordable makes boards like that.

That violet mask is the closest thing I've seen to KiCAD's fantasies.

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Lardo Boffin
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Re: Done scratching that itch

Post by Lardo Boffin » Wed Nov 27, 2019 12:04 am

I think someone on eBay was offering a service to have the major parts of your A500+ transplanted to one of those boards presumably to repair it. It was a few hundred pounds.
Atom, issue 5
Elk
BBC model B 32k issue 4, 16k sideways RAM, Watford 12 ROM board, Acorn 6502 coproc
BBC model B 32k issue 7, turboMMC, Opus Challenger 3 512k, Pi 3 coproc
USA Model B
BBC Master, Datacentre + HDD, pi co-proc, econet, NULA

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anightin
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Re: Done scratching that itch

Post by anightin » Wed Nov 27, 2019 7:54 am

Lardo Boffin wrote:
Wed Nov 27, 2019 12:04 am
I think someone on eBay was offering a service to have the major parts of your A500+ transplanted to one of those boards presumably to repair it. It was a few hundred pounds.
Yup I’ve seen thar advert — building this board was tedious in places but on balance very therapeutic. I really enjoyed sourcing the parts and putting it all together too. The moment you apply power and hope for the best is quite nerve wracking, but wow the sense of achievement when you see that boot screen!

I’ll be keeping my few hundred, and putting some of that towards Rob’s next recreation — an Archimedes A3000 PCB 😍

It’s anyones guess on colour — yellow? Orange?

cmorley
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Re: Done scratching that itch

Post by cmorley » Wed Nov 27, 2019 8:28 am

Now get it a lovely new 2MB RAM expansion for 2MB chip and 1MB slow :-

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trixster
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Re: Done scratching that itch

Post by trixster » Wed Nov 27, 2019 10:55 am

Great work Andy, looks fantastic!

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marcusjambler
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Re: Done scratching that itch

Post by marcusjambler » Wed Nov 27, 2019 1:32 pm

Great job Andy... =D>

I keep drooling over that board myself #-o

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Lardo Boffin
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Re: Done scratching that itch

Post by Lardo Boffin » Wed Nov 27, 2019 2:00 pm

anightin wrote:
Wed Nov 27, 2019 7:54 am

The moment you apply power and hope for the best is quite nerve wracking, but wow the sense of achievement when you see that boot screen!
I know what you mean. Not quite the same but I took a dead ZX81 and removed every component, sourced everything new and rebuilt it using the original assembly instructions. Turned the power on and got nothing! After much mucking around with bits it turned out the oscillator was not working. Popped in another one and all was well.

Not as cool but...

BB98EE54-74EF-40FC-8D3C-C058590B830C.jpeg
Atom, issue 5
Elk
BBC model B 32k issue 4, 16k sideways RAM, Watford 12 ROM board, Acorn 6502 coproc
BBC model B 32k issue 7, turboMMC, Opus Challenger 3 512k, Pi 3 coproc
USA Model B
BBC Master, Datacentre + HDD, pi co-proc, econet, NULA

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anightin
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Re: Done scratching that itch

Post by anightin » Wed Nov 27, 2019 4:19 pm

Lardo Boffin wrote:
Wed Nov 27, 2019 2:00 pm
...Popped in another one and all was well.
Great that you got to the bottom of the issue, build looks very smart.


My donor A500+ wasn't working when I bought it, it's symptoms were that it kept posting spurious data into the keyboard buffer. The buffer would fill then lock up the machine. Looks like the previous owner had replaced the CIA Chips, and the keyboard and then given up and put the machine on eBay. I traced it down to a bad connection on a decoupling capacitor on the motherboard, half an hour later the machine was full working again :)

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