Just bought an Atom

discussion of games, software, hardware & emulators relating to the Acorn Atom and Acorn System machines.
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Lardo Boffin
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Just bought an Atom

Post by Lardo Boffin » Sun Feb 24, 2019 2:56 pm

In a fit of probable madness I have just bought an Atom on eBay. Working status unknown. :? But then it was the cheapest one I have seen in a long time.

It doesn’t come with a PSU. What am I likely to need for one and any ideas where I can get one? From what I have read of other peoples threads on here it may require non-standard power?

Will post pictures when it arrives. :D
Atom, issue 5
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BBC model B 32k issue 7, turboMMC, Opus Challenger 3 512k, Pi 3 coproc
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hoglet
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Re: Just bought an Atom

Post by hoglet » Sun Feb 24, 2019 3:04 pm

It looks like a nice clean issue 5.

Dave

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AndyF
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Re: Just bought an Atom

Post by AndyF » Sun Feb 24, 2019 3:15 pm

:D Excellent.

http://www.beebmaster.co.uk/Atom/AtomPSU.html and https://www.beebmaster.co.uk/BeebHelp/AtomPower.html

EDIT... And > viewtopic.php?t=14852

Personally though I'd simply await to see what arrives first, with regard to you may need a few other bits first. It may of been modified in which case it could require a different PSU type. I'm thinking here of along the lines of a 780x / 790x regulator fitted etc. If memory serves it had/has two by default, someone may of fitted solid-state replacements and/or done other works.
Last edited by AndyF on Sun Feb 24, 2019 3:18 pm, edited 3 times in total.
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oss003
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Re: Just bought an Atom

Post by oss003 » Sun Feb 24, 2019 3:39 pm

Hi Lardo,

you don't have to be mad to buy an Atom ........ :lol:

If you bypass the voltage regulators and the Atom isn't packed with expansions, a 2A 5V USB power supply is ok.
You do have to find a plug which fits but you can find the right type on this forum: viewtopic.php?f=44&t=13633

Greetings
Kees
Last edited by oss003 on Sun Feb 24, 2019 3:40 pm, edited 1 time in total.

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roland
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Re: Just bought an Atom

Post by roland » Sun Feb 24, 2019 4:21 pm

Is that the one that is still listed on EBay?
FPGAtom: 512 KB RAM, Real Time Clock and 64 colours
MAN WOMAN :shock:

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trixster
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Re: Just bought an Atom

Post by trixster » Sun Feb 24, 2019 5:29 pm

Get an AtoMMC, one of Prime’s RAM/ROM boards, a Colour Card, a Tube Interface and a Matchbox Copro. Win!
A3020 | A3000 | A420/1 | BBC B | Master Turbo | ZX48K | NeoGeo
Atom | Amiga A4000 | A3000 | A1200 | A500 | PC Engine | Enterprise
Falcon | Saturn | PS1 | SNES | CPC6128 | C64 | 3DO | MD | Jaguar | X68000 | CD32

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Lardo Boffin
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Re: Just bought an Atom

Post by Lardo Boffin » Sun Feb 24, 2019 5:46 pm

AndyF wrote:
Sun Feb 24, 2019 3:15 pm
:D Excellent.

http://www.beebmaster.co.uk/Atom/AtomPSU.html and https://www.beebmaster.co.uk/BeebHelp/AtomPower.html

EDIT... And > viewtopic.php?t=14852

Personally though I'd simply await to see what arrives first, with regard to you may need a few other bits first. It may of been modified in which case it could require a different PSU type. I'm thinking here of along the lines of a 780x / 790x regulator fitted etc. If memory serves it had/has two by default, someone may of fitted solid-state replacements and/or done other works.
Thanks for the links. :D
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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Lardo Boffin
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Re: Just bought an Atom

Post by Lardo Boffin » Sun Feb 24, 2019 5:47 pm

oss003 wrote:
Sun Feb 24, 2019 3:39 pm

you don't have to be mad to buy an Atom ........ :lol:
Its more that it is untested and may cost a small fortune to fix. :D
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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Lardo Boffin
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Re: Just bought an Atom

Post by Lardo Boffin » Sun Feb 24, 2019 5:48 pm

roland wrote:
Sun Feb 24, 2019 4:21 pm
Is that the one that is still listed on EBay?
I hope not! Are you looking at the one for around £400?
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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Lardo Boffin
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Re: Just bought an Atom

Post by Lardo Boffin » Sun Feb 24, 2019 5:49 pm

trixster wrote:
Sun Feb 24, 2019 5:29 pm
Get an AtoMMC, one of Prime’s RAM/ROM boards, a Colour Card, a Tube Interface and a Matchbox Copro. Win!
Sweet. I was maybe hoping to connect it to my econet as well. 8)
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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oss003
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Re: Just bought an Atom

Post by oss003 » Sun Feb 24, 2019 6:41 pm

You can find info about Atom expansions here: viewtopic.php?f=13&t=8168&p=86259&hilit ... ard#p86259

Greetings
Kees

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roland
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Re: Just bought an Atom

Post by roland » Sun Feb 24, 2019 7:35 pm

Lardo Boffin wrote:
Sun Feb 24, 2019 5:47 pm

Its more that it is untested and may cost a small fortune to fix. :D
don't worry, Atom parts are easy to get and quite cheap. As long as the main board is in good condition all will be fine :D
FPGAtom: 512 KB RAM, Real Time Clock and 64 colours
MAN WOMAN :shock:

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KenLowe
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Re: Just bought an Atom

Post by KenLowe » Mon Feb 25, 2019 12:05 am

oss003 wrote:
Sun Feb 24, 2019 3:39 pm
you don't have to be mad to buy an Atom ........ :lol:
... but it does help :lol: :lol:

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Re: Just bought an Atom

Post by Prime » Mon Feb 25, 2019 1:30 am

roland wrote:
Sun Feb 24, 2019 7:35 pm
don't worry, Atom parts are easy to get and quite cheap. As long as the main board is in good condition all will be fine :D
Seconded all reasonably standard chips, weirdest ones are the 8304 and 81LS95, though I think the beeb also uses the latter.

Cheers.

Phill.

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Re: Just bought an Atom

Post by DutchAcorn » Mon Feb 25, 2019 5:38 am

The Atom takes 5V regulated if you bypass the 7805's (which is a good idea in any case). 5V PSU's are not hard to come by. For a fully expanded Atom 3A capacity is advised (see the Atom Technical Manual).

A plug that fits the power socket can be hard to find. See this thread: viewtopic.php?p=178619#p178598

No need to resort to replacing the original power socket though; I have a few spare plugs if you have trouble finding one.
Paul

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1024MAK
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Re: Just bought an Atom

Post by 1024MAK » Mon Feb 25, 2019 11:54 am

Yeah, lots of good advice above. Just check if the on board 5V regulators are bypassed or not before applying power.

If they are bypassed, use a 5V regulated power supply (e.g. USB 5V power supply).
If they are not bypassed, then a 7.5V to 9V regulated, or a 8V to 9V unregulated DC power supply is normally used. You can use slightly higher voltages, but then the heat sink runs hotter. Okay for occasional short term use, but not preferred if you will be using it a lot.

Obviously double triple check polarity before connecting any power supply.

If you’re not sure, post up some photos and all the Atom hardware geeks can advise further :mrgreen:

Mark

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roland
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Re: Just bought an Atom

Post by roland » Mon Feb 25, 2019 8:10 pm

Prime wrote:
Mon Feb 25, 2019 1:30 am
Seconded all reasonably standard chips, weirdest ones are the 8304 and 81LS95.
Last week I ordered a few of those on Ebay. Still widely available for $2 - $2.5.
FPGAtom: 512 KB RAM, Real Time Clock and 64 colours
MAN WOMAN :shock:

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Lardo Boffin
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Re: Just bought an Atom

Post by Lardo Boffin » Thu Feb 28, 2019 12:12 pm

It just arrived (badly packaged but luckily intact) so here are some photos. I don’t know why but I thought it would be bigger?

Its an issue 5 so full marks to Hoglet. :D

097B648C-9C0C-43D9-B663-9B5FF47E1B21.jpeg
D3AD57BF-B9E8-4188-800D-4A68570D4566.jpeg
Some brown stuff on the PCB.
E03FA56C-1BBD-4597-8667-5556824D7255.jpeg
E8CE7AB1-5E54-4DA6-A679-2887C6639AD6.jpeg
86289A1E-64EE-42F9-BEFD-2A8643A00C78.jpeg
269BA011-EAE6-4DB5-9E81-1410FA36D815.jpeg
17A2F281-AF33-48B8-A19D-D1E19A93D195.jpeg
DD913F13-66E1-4B22-9533-72B411FAF6B9.jpeg
So I guess not too bad!

How do I determine whether it is 5V or 8V? Presumably some close ups of somewhere are required?

I assume the 5V mod is the ‘best practice’ for these?

Thanks

Lardo
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
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Re: Just bought an Atom

Post by jms2 » Thu Feb 28, 2019 12:31 pm

Lardo Boffin wrote:
Thu Feb 28, 2019 12:12 pm
How do I determine whether it is 5V or 8V? Presumably some close ups of somewhere are required?
Yes - if you look just "under" the heatsink, there will be two (I think?) voltage regulators if it is an 8V machine. The 5V mod involves removing these.
I assume the 5V mod is the ‘best practice’ for these?
Yes, that's my understanding, because it avoids the considerable heat that is generated by the regulators.

That's a beautiful machine by the way! :D
Last edited by jms2 on Thu Feb 28, 2019 12:33 pm, edited 1 time in total.

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Re: Just bought an Atom

Post by 1024MAK » Thu Feb 28, 2019 12:33 pm

Short answer, yes if you have a suitable 5V 2A (or greater current) power supply unit. If you want the long answer / other options, ask!

Wire links LK6 and LK7 are fitted to bypass the two 5V regulators (LM340T-5 or 7805 or equivalents).
These links are physically near the regulators (the heatsink blocks the view of them when an overhead photo is taken).
But it looks like LK7 is not fitted. So LK6 is unlikely to be fitted as well.

There are some schematic diagrams in this thread.

If you are not sure about the configuration, only apply a 5V supply. You can then test the 5V pins on some of the chips. If it is significantly less than 5V, the bypass links are not fitted.

ETA: the presence of the voltage regulators and their heatsink does not always mean that the board is congfigured for 8V to 9V operation. If links LK6 and LK7 are fitted, it is optional whether the heatsink / regulators are removed or not.

Mark
Last edited by 1024MAK on Thu Feb 28, 2019 12:39 pm, edited 2 times in total.

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Re: Just bought an Atom

Post by Prime » Thu Feb 28, 2019 4:51 pm

Looks good, you have :

6K of CPU RAM, 2K of video RAM, Both integer & floting point ROMS. You don't have the printer port, bus buffers or 6522 fitted. And it looks like someone tried ignoring the advice in the Dragon manual not to feed coputers Tea and Coffee.......

You do have the video header fitted so you can take composite from it. It's the 2x5 pin header next to the power plug, one will be ground the other video.

Once you turn it on even without a monitor you can usually tell if the machine is working by hitting break and then typing CTRL-G a few times and you should hear it beep.

Cheers.

Phill.

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Lardo Boffin
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Re: Just bought an Atom

Post by Lardo Boffin » Fri Mar 01, 2019 9:37 am

Here is a photo of the regulators and link 6:-

7835A194-DC27-4034-9C00-9ECCABD98B56.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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Lardo Boffin
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Re: Just bought an Atom

Post by Lardo Boffin » Fri Mar 01, 2019 9:38 am

And a quick clean of the board. Most of the brown stuff is gone.

25FA0C38-8FBF-4782-86D4-D465E17A7334.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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danielj
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Re: Just bought an Atom

Post by danielj » Fri Mar 01, 2019 9:39 am

Looks like the regs haven't been bypassed. I'd fit links 6 and 7 and get a regulated 5V 3A supply. :)

d.

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1024MAK
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Re: Just bought an Atom

Post by 1024MAK » Fri Mar 01, 2019 10:58 am

Lardo Boffin wrote:
Fri Mar 01, 2019 9:37 am
Here is a photo of the regulators and link 6:-
Yeah, link LK6 does not look like it’s fitted.

What test gear do you have?
What DC power supplies do you have?

Mark

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Lardo Boffin
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Re: Just bought an Atom

Post by Lardo Boffin » Fri Mar 01, 2019 11:33 am

1024MAK wrote:
Fri Mar 01, 2019 10:58 am
Lardo Boffin wrote:
Fri Mar 01, 2019 9:37 am
Here is a photo of the regulators and link 6:-
Yeah, link LK6 does not look like it’s fitted.

What test gear do you have?
What DC power supplies do you have?

Mark
A multi-meter and not sure about DC supplies yet. I have a bunch of wall wart types but not checked out their ratings.

I’m currently edging towards sending this to someone that knows what they are doing so I don’t risk breaking it.
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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roland
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Re: Just bought an Atom

Post by roland » Fri Mar 01, 2019 4:23 pm

Congratulations, you have got yourself a nice Atom. We will get this working if it doesn't already =D>
And I am a bit jealous because you have a real floating point rom; I never had one =P~
FPGAtom: 512 KB RAM, Real Time Clock and 64 colours
MAN WOMAN :shock:

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anightin
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Re: Just bought an Atom

Post by anightin » Mon Mar 04, 2019 4:37 pm

Mine just arrived in the post so will open it up and fit an AtoMMC as soon as I've finished my System1 build.
IMG_2843.jpeg

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Lardo Boffin
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Re: Just bought an Atom

Post by Lardo Boffin » Wed Mar 06, 2019 12:52 am

Is it possible to do a Spectrum type composite mod on these?
Given that I have the video out header pins present presumably it would be possible to desolder the wire(s) going into the modulator and pass in a feed from these pins?
That would avoid having to make up some sort of cable to connect to the pins which would be extremely inconvenient to plug in and unplug.
Or is the point of the pins to be able to add a socket that then allows a cable to be plugged into it via the gap in the case?
Thanks!
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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tricky
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Re: Just bought an Atom

Post by tricky » Wed Mar 06, 2019 6:48 am

That is a common mod including my atom but I don't have the details.

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