Acorn atom repair

emulators, hardware and classic software for atom + system machines
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Shaggy
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Acorn atom repair

Post by Shaggy » Sun May 03, 2020 4:46 pm

Hi all
New here after recently acquiring an atom off eBay finally . I have been reading through plenty of boards and info available and as is with most things the first job was to have a look inside .
It's an issue 5 board and looks to be quite heavily modded . See pic .
It came without a power supply so the first thing was to figure this out . Any tips would be helpful .as there's no regulators I'm assuming it requires 5v but there is an extra socket fitted on the back where the red wires go to .no regulators fitted .
There is also an additional board fitted on the rhs which I have no idea about .
I intend printing off a load of drawings etc to see if I can understand what's going on when I get chance put any pointers would be helpful
IMG_20200503_085712.jpg

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Multiwizard
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Re: Acorn atom repair

Post by Multiwizard » Sun May 03, 2020 5:22 pm

Welcome,

nice Atom... :D

And a nice (for me) unknown colour? board too... :D


Greetings Wim... :-)

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roland
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Re: Acorn atom repair

Post by roland » Sun May 03, 2020 5:24 pm

Hi Shaggy,

Welcome to this forum. Your Atom does not look that heavy modded, it's just the (program) memory is expanded with 1K. The board looks like a colour board, considered the position and how it is mounted.

You need a 5V power supply that can provide 2 - 3A. Make sure that you don't swap the + and - of the power supply.

Waiting to get news from you after power on. If it doesn't work, don't fear ..... we will fix it :lol:

Greetings from the South of the Netherlands,
Roland
FPGAtom: 512 KB RAM, Real Time Clock and 64 colours
MAN WOMAN :shock:

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JudgeBeeb
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Re: Acorn atom repair

Post by JudgeBeeb » Sun May 03, 2020 5:26 pm

The daughter board has a crystal which is marked 4433.615 kHz (or, more, conventionally 4.433615 MHz). This is the PAL colour burst frequency. So, it is probably a colour board. It is not the Acorn official one. Indeed, it may be a home-brew. The more knowledge Atom enthusiasts can probably give you a more definitive answer.

Why don't you join the next Acorn Virtual Session on 16 May and we can do a group assessment of your Atom. :D
There is so much wonder in the universe; why should you want to imagine that there is more?

Shaggy
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Re: Acorn atom repair

Post by Shaggy » Sun May 03, 2020 5:45 pm

Wow thanks for the quick replies guys. I've only just started delving in so I'll update when I've tried it . I also noticed ic 18and 19 have ics literally piggy backed ontop of the ones in the socket ,not sure why yet suspect I'll be able to update more once I apply power and see what we have .
Anyone got ideas what the link wires are for near the middle of the board . ? Tia
I take it the extra socket on the back is for the 5v PSU but this looks like an earphone jack socket although has 4 wires coming from it. The 2 red which look like the main 5vdc supply and the purple and yellow which go through to the keyboard . Not sure why they aren't commoned together here ie the purple and the other red wire ,any ideas ?
IMG_20200503_180123.jpg
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IMG_20200503_180059.jpg

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oss003
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Re: Acorn atom repair

Post by oss003 » Sun May 03, 2020 6:41 pm

Hi Shaggy,

The piggybacked IC's are for extra RAM at #3C00-#3FFF, the 1KB Roland was talking about. The chip select lines are the red and orange wires.

Don't know exactly what the red wires are but the yellow/purple wires are probably going to the speaker.

Greetings
Kees
Last edited by oss003 on Sun May 03, 2020 6:46 pm, edited 1 time in total.

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roland
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Re: Acorn atom repair

Post by roland » Sun May 03, 2020 6:42 pm

The extra ear phone jack is for an ear phone, amplifier or external speaker, do not connect this to 5V power supply !

The red wires come from the LS connection on the main board and the yellow and pink wires go to the speaker on the keyboard side.
FPGAtom: 512 KB RAM, Real Time Clock and 64 colours
MAN WOMAN :shock:

Shaggy
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Re: Acorn atom repair

Post by Shaggy » Sun May 03, 2020 6:47 pm

Are ok that makes sense thanks . Going to dig out my 5v PSU tomorrow and apply some power . I managed to buy some plugs for the power already and now I know it's 5v and where to connect will give it a go .

Once I get it up and running I'll be giving the retrobrite a go although I have a zx80 I'll be testing it in first as I have a few of those to play with .

Great site guys thanks for he help

John Ferguson
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Re: Acorn atom repair

Post by John Ferguson » Sun May 03, 2020 6:55 pm

The Atom has the colour board which is identical to the one I have hence it’s probably a commercial product.

It connects to C2 and PL4.

John

Shaggy
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Re: Acorn atom repair

Post by Shaggy » Sun May 03, 2020 7:03 pm

Interesting . Will have a look around see if it has any info on it or if I can locate a drawing for it at some point now I know it's not a home brew board . Thanks

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oss003
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Re: Acorn atom repair

Post by oss003 » Sun May 03, 2020 7:14 pm

It looks a bit like this one .....
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colour_card.gif

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oss003
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Re: Acorn atom repair

Post by oss003 » Sun May 03, 2020 7:19 pm

Or this one ....
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atom_colour_encoder_cct.png

bprosman
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Re: Acorn atom repair

Post by bprosman » Tue May 05, 2020 2:43 pm

Do you know anything about the quality of this board Kees ? Meaning the picture quality.

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Multiwizard
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Re: Acorn atom repair

Post by Multiwizard » Tue May 05, 2020 3:04 pm

I still need to build/mount & test this nice Delft Colour board, see pic below

http://www.acornatom.nl/atom_nieuws/198 ... 842086.htm

But there are so many nice things to do in so little time :( but I will... 8)


Greetings, Wim... :-)
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P1330151 Delft Colour board.JPG

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oss003
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Re: Acorn atom repair

Post by oss003 » Tue May 05, 2020 3:06 pm

I must say that I have never seen a real one ..... so I don't know but it's probably RF out so not that good ....
Maybe John can help you vecause he said he had a simular one.

Greetings
Kees

John Ferguson
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Re: Acorn atom repair

Post by John Ferguson » Wed May 06, 2020 9:01 am

oss003 wrote:
Tue May 05, 2020 3:06 pm
I must say that I have never seen a real one ..... so I don't know but it's probably RF out so not that good ....
Maybe John can help you vecause he said he had a simular one.

Greetings
Kees
Here is the output from this colour board. I thought that it was excellent.

John
20180427_091355_resized.jpg

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oss003
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Re: Acorn atom repair

Post by oss003 » Wed May 06, 2020 9:42 am

For RF ok ..... but RGB, VGA or HDMI quality is much, much better ....

viewtopic.php?f=44&t=16907
viewtopic.php?f=44&t=5994

Greetings
Kees

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