Help - new atom user

discussion of games, software, hardware & emulators relating to the Acorn Atom and Acorn System machines.
Post Reply
Dggmcilroy
Posts: 4
Joined: Sat Aug 25, 2018 4:50 pm
Contact:

Help - new atom user

Post by Dggmcilroy » Sat Aug 25, 2018 5:24 pm

Hi all,

I’m happy to be on your site, although unashamedly looking for help.

Got an atom a few days ago and very excited, though there is a but. Although I’m a late 40 something and have had many Sinclair, Amstrad and commodore’s, as well as a bbc b, oric and dragon 32, I’ve never had an atom, electron or Archimedes.

Carefully plugged the ‘new’ atom in....... tuned in ch36...... and waited...... I get what looks like a QR code with alpha numerics on it.

I’ve tried on two other sets, including an old crt that happily displays on uhf my speccy and zx81.

I’m getting about 12v with no load. I’ve got an original acorn psu and it looks like the original uhf cable.

Engineering isn’t my thing, so technically I’m not au fait with the boards and circuits. A cursory glance suggests all chips are well seated.

Any thoughts? Is it my tv(s)? I read the output is 60hz and that sometimes fiddling with vertical hold is needed?
Attachments
5AE0E3D4-4197-41C1-BC1B-11531374873F.jpeg

User avatar
Lardo Boffin
Posts: 1279
Joined: Thu Aug 06, 2015 6:47 am
Contact:

Re: Help - new atom user

Post by Lardo Boffin » Sat Aug 25, 2018 5:49 pm

Have you pressed Break after switching it on?
BBC model B 32k issue 4, 16k sideways RAM, Watford 12 ROM board, Viglen twin 40/80 5.25" discs, Acorn 6502 coproc
BBC model B 32k issue 7, turboMMC, Opus Challenger 3 512k, Pi 3 coproc
BBC Master, Datacentre + HDD, pi co-proc

User avatar
hoglet
Posts: 7511
Joined: Sat Oct 13, 2012 6:21 pm
Location: Bristol
Contact:

Re: Help - new atom user

Post by hoglet » Sat Aug 25, 2018 6:09 pm

Hello and welcome!

Can you post some photos of your atom board:
- some of the whole board
- a close up of the area around the heat sink

If you are using the original (unregulated) supply, it's very important to make sure the 5V regulators have not been bypassed. Otherwise you end up feeding 8V into pretty much every chip, which usually causes a lot of damage.

Also, it looks like you are getting stable video, so the TV/monitor is working fine and there is no need to mess with the vertical hold.

Dave
Last edited by hoglet on Sat Aug 25, 2018 6:10 pm, edited 2 times in total.

User avatar
flaxcottage
Posts: 3243
Joined: Thu Dec 13, 2012 8:46 pm
Location: Derbyshire
Contact:

Re: Help - new atom user

Post by flaxcottage » Sat Aug 25, 2018 7:09 pm

Welcome. :D
- John
Image

Kazzie
Posts: 204
Joined: Sun Oct 15, 2017 7:10 pm
Location: North Wales
Contact:

Re: Help - new atom user

Post by Kazzie » Sat Aug 25, 2018 8:33 pm

Hi, and welcome!

You've clearly got a very forward-looking Atom if it's generating QR barcodes for you.

In all seriousness, I'll second Hoglet's observation that your TV is fine: it looks like it's faithfully representing the data sent to it by the Atom. The issue now is working out what it is inside the Atom that's causing it to send garbage characters out to the TV.
BBC Model B 32k issue 7, Sidewise ROM board with 16K RAM
Archimedes 420/1 upgraded to 4MB RAM (mid- restoration)
Acorn System 1 home-made replica

User avatar
oss003
Posts: 2780
Joined: Tue Jul 14, 2009 11:57 am
Location: Netherlands
Contact:

Re: Help - new atom user

Post by oss003 » Sun Aug 26, 2018 5:59 am

Welcome,

Nice to have another Atom user at Stardot and enjoy the forum.

Sometimes it will help to remove every IC one by one, clean it's legs and put it back a few times. It could be that some contacts are corroded.

Here's a little guide to help you getting your Atom working: viewtopic.php?f=44&t=6318&p=60505&hilit ... ion#p60505

If you are looking for some extensions boards or Atomic software, have a look at this post: viewtopic.php?f=13&t=8168&p=86259&hilit ... ard#p86259

Greetings
Kees
Last edited by oss003 on Sun Aug 26, 2018 6:07 am, edited 2 times in total.

Dggmcilroy
Posts: 4
Joined: Sat Aug 25, 2018 4:50 pm
Contact:

Re: Help - new atom user

Post by Dggmcilroy » Sun Aug 26, 2018 10:02 am

Hi all,

Thanks for your welcome and obs.

I’ve tried pressing break after starting. Makes no difference to the screen.

Some pics attached of the board. The expansion board for some reason on arrival wasn’t connected to the man board. I know not why. Either way I didn’t get a display when it wasn’t and no display when it is.

I Can remove the ice chips as has been suggested to see if that makes any difference and thanks for the link.

Some pics for ref. I haven’t removed the expansion board now I plugged it in, but could if that would be helpful.

Thanks,

David
Attachments
085ECA10-D61D-4584-9BAA-2FB47E33068D.jpeg
82C68C11-E198-4EFC-B858-E827C2EC7CCD.jpeg
BC0FF334-1C1B-4752-8B8F-5F29D9C47060.jpeg
64CFDA73-04DF-4D9B-AA46-8061343B5313.jpeg
1941708A-E74E-45F8-BDA3-2FB9A792CDC4.jpeg
82E0F09A-9C76-4A36-A30F-7420A6A6BF0C.jpeg
EB9D31B9-4A0C-4675-8C03-F60DF91339C9.jpeg
097ACAC6-AF85-4EE8-8DBF-03B2727E58F5.jpeg
AEF9DAB9-928B-450C-B186-698B901FE777.jpeg

Dggmcilroy
Posts: 4
Joined: Sat Aug 25, 2018 4:50 pm
Contact:

Re: Help - new atom user

Post by Dggmcilroy » Sun Aug 26, 2018 10:17 am

Further to last, I unplugged the expansion board and so attach some more pics.

Thought though, given it look some gentle persuasion to get it off, there is no way it came off during transit so had been left that way before shipping. As I don’t know the what is on the expansion board I can’t speculate why.
Attachments
B2CF577A-7A0C-4AB8-892C-04CE6199FB96.jpeg
9B08AC3B-C781-476F-839A-5D1B92E15EF6.jpeg
DD54F6C0-8D7B-4603-A380-F7680FF9931E.jpeg
00951E7A-D052-4575-8F88-A9BCEB8DC7B4.jpeg
A8044993-11C9-4FDB-B8DE-33AF8C8FD62E.jpeg
0F1CF168-F764-4E3F-B2C1-A11B5A806144.jpeg

User avatar
hoglet
Posts: 7511
Joined: Sat Oct 13, 2012 6:21 pm
Location: Bristol
Contact:

Re: Help - new atom user

Post by hoglet » Sun Aug 26, 2018 10:32 am

David,

Thanks for the photos.

That's quite an unusual configuration, which complicates things a bit:
- The base Atom only has 2K of RAM fitted
- The expansion board adds a further 16K implemented with 8x 4116 DRAM (with room for a further 16K)
- The expansion board also contains a switching power supply.

The 4116 DRAM chips I think need several power supply voltages: -5V, +5V and +12V. That's probably the purpose of the switching supply.

I didn't quite understand the following sentence:
Either way I didn’t get a display when it wasn’t and no display when it is.
It's just possible that the switching power supply on the expansion board is powering the whole Atom.

Do you have a multi meter, and know how to use it?

I would start off with the expansion board removed, and check that each of the Atom chips is receiving 5V (measure directly across the power supply pins of each chip, taking care not to short anything).

Once you have verified each of the chips is correctly powered, you can move on to the next stage.

A common failure on the Atom is the 2114L RAM chips. A failed RAM chip in IC51/52 will prevent the Atom from starting. It would be worth swapping the 2114L RAM chips over (i.e. swap the pair in IC 42/43 with the pair in IC51/52), and see if that changes the symptoms.

Dave
Last edited by hoglet on Sun Aug 26, 2018 10:33 am, edited 2 times in total.

Dggmcilroy
Posts: 4
Joined: Sat Aug 25, 2018 4:50 pm
Contact:

Re: Help - new atom user

Post by Dggmcilroy » Sun Aug 26, 2018 10:39 am

I don’t understand all of that, but I have a friend with a multi meter who will.

The sentence you refer to... with or without the expansion board plugged in, the screen display was the same as the first pic I sent.

Thanks for your guidance to date, I’ll let you know how I get on.

David.

User avatar
hoglet
Posts: 7511
Joined: Sat Oct 13, 2012 6:21 pm
Location: Bristol
Contact:

Re: Help - new atom user

Post by hoglet » Sun Aug 26, 2018 10:41 am

Dggmcilroy wrote:
Sun Aug 26, 2018 10:39 am
The sentence you refer to... with or without the expansion board plugged in, the screen display was the same as the first pic I sent.
That's good - that means the switching power supply on the expansion board is only powering the expansion board.

Dave

User avatar
hoglet
Posts: 7511
Joined: Sat Oct 13, 2012 6:21 pm
Location: Bristol
Contact:

Re: Help - new atom user

Post by hoglet » Sun Aug 26, 2018 10:45 am

Here is a link to the manual for your RAM expansion board:
viewtopic.php?f=44&t=13338

The RAM expansion board looks like it is correctly configured to map the 16K RAM at addresses #2800-#67FF.

This leaves IC 52/53 providing #0000-#03FF and IC 41/42 providing #8000-#83FF

Dave
Last edited by hoglet on Sun Aug 26, 2018 10:59 am, edited 1 time in total.

Post Reply