Search found 143 matches

by John Ferguson
Tue May 26, 2020 6:46 pm
Forum: acorn atom and acorn system series
Topic: Noise killer board and HDMI interface
Replies: 6
Views: 86

Re: Noise killer board and HDMI interface

I have a colour board with the output connected to C2 and then on to the modulator. Is there anyway this type of output could be diverted to the HDMI interface? The HDMI adapter doesn't need an internal colour board to function. It decodes the colour signals that the 6847 generated directly. These ...
by John Ferguson
Tue May 26, 2020 4:55 pm
Forum: acorn atom and acorn system series
Topic: Noise killer board and HDMI interface
Replies: 6
Views: 86

Re: Noise killer board and HDMI interface

Dave

Many thanks Dave for the answers.

I have a colour board with the output connected to C2 and then on to the modulator.

Is there anyway this type of output could be diverted to the HDMI interface?

Regards

John
by John Ferguson
Tue May 26, 2020 4:37 pm
Forum: acorn atom and acorn system series
Topic: Noise killer board and HDMI interface
Replies: 6
Views: 86

Re: Noise killer board and HDMI interface

Thanks Roland

What can yo say about fitting the noise killer board and the HDMI interface together in the same Atom?

Regards

John
by John Ferguson
Tue May 26, 2020 4:18 pm
Forum: acorn atom and acorn system series
Topic: Noise killer board and HDMI interface
Replies: 6
Views: 86

Noise killer board and HDMI interface

Hi Dave

Nearly finished assembling the noise killer board but am wondering about the following.

The IC specified for U5 is a 32k device.

Is this amount of memory available for programmes?

Can you fit both the noise killer board and the HDMI interface?

Regards

John
by John Ferguson
Thu May 21, 2020 10:49 am
Forum: acorn atom and acorn system series
Topic: Composite video from the Atom
Replies: 1
Views: 104

Composite video from the Atom

I have been fine tuning the output from my colour board as seen on a TV via the modulator.

The output from the colour board is connected to C2.

The question is if I connect pins 9 and 10 of PL4 to the composite video connection on the TV will I get a better quality colour picture?

John
by John Ferguson
Wed May 20, 2020 1:54 pm
Forum: acorn atom and acorn system series
Topic: Replacement power jack for Atom
Replies: 6
Views: 237

Re: Replacement power jack for Atom

I have just fitted a standard DC power connector to my Atom as the existing one was very worn and loose. The 0v legs needed to be bent slightly and the power tab cut off level with the connector and soldered to connect to the Atom PCB. Where it obstructed the case next to the DIN connector a small a...
by John Ferguson
Sun May 10, 2020 11:08 am
Forum: acorn atom and acorn system series
Topic: Another Atom acquired not working
Replies: 23
Views: 716

Re: Another Atom acquired not working

I have several of those roms available. You can have one for P&P, that's €7.50 from the Netherlands to the UK. But I think there will also be some roms available in your country which will have less P&P costs. Yes please Roland. I will PA you with my address. Please let me know how to pay you. Rega...
by John Ferguson
Sun May 10, 2020 10:59 am
Forum: acorn atom and acorn system series
Topic: Atom Printing
Replies: 13
Views: 2038

Re: Atom Printing

Hmmm, looks like RXBOX is not compatible with my printer. I also hadn't realized the standard printer port on the Atom was 7 bits, and not 8 bits. I found a listing in Acorn User, November 1985, page 193/195 that does a Screen Dump and only needs a 7 bit interface: http://8bs.com/cgi-bin/magsel.cgi...
by John Ferguson
Sun May 10, 2020 9:59 am
Forum: acorn atom and acorn system series
Topic: Another Atom acquired not working
Replies: 23
Views: 716

Re: Another Atom acquired not working

This Atom only works with the basic ROM from another working Atom inserted in the IC20 position.

Is is possible that a member of this forum could supply me with a replacement IC at cost?

I realise that this ROM is no longer available but someone may have a spare.

John
by John Ferguson
Wed May 06, 2020 9:01 am
Forum: acorn atom and acorn system series
Topic: Acorn atom repair
Replies: 16
Views: 397

Re: Acorn atom repair

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
by John Ferguson
Sun May 03, 2020 6:55 pm
Forum: acorn atom and acorn system series
Topic: Acorn atom repair
Replies: 16
Views: 397

Re: Acorn atom repair

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
by John Ferguson
Fri May 01, 2020 1:22 pm
Forum: acorn atom and acorn system series
Topic: Atom noise killer board
Replies: 1
Views: 147

Atom noise killer board

Dave

I have sent you a private message about problems I am having with the noise killer board.

I expect I have misunderstood the assembly instructions.

Regards

John
by John Ferguson
Sun Apr 26, 2020 7:54 pm
Forum: acorn atom and acorn system series
Topic: Another Atom acquired not working
Replies: 23
Views: 716

Re: Another Atom acquired not working

Yes dealing with problems is part of learning but it is frustrating at times. The pleasure when you have solved them is well worth waiting for. I learnt a lot.

John
by John Ferguson
Sun Apr 26, 2020 6:05 pm
Forum: acorn atom and acorn system series
Topic: Another Atom acquired not working
Replies: 23
Views: 716

Re: Another Atom acquired not working

I believe that if the Atom boots and you can hear errors like this, then the 6847 must at-least be generating the VSYNC signal. So this means that the video clock is likely to be running. Asking as a sheer Atom novice, how would a lack of VSYNC / video clock signal stop the Atom from booting? Dave ...
by John Ferguson
Sun Apr 26, 2020 3:51 pm
Forum: acorn atom and acorn system series
Topic: Another Atom acquired not working
Replies: 23
Views: 716

Re: Another Atom acquired not working

I believe that if the Atom boots and you can hear errors like this, then the 6847 must at-least be generating the VSYNC signal. So this means that the video clock is likely to be running. Asking as a sheer Atom novice, how would a lack of VSYNC / video clock signal stop the Atom from booting? Dave ...
by John Ferguson
Sun Apr 26, 2020 1:24 pm
Forum: acorn atom and acorn system series
Topic: Another Atom acquired not working
Replies: 23
Views: 716

Re: Another Atom acquired not working

You can also check the voltage of the clock signal. If there's no clock at all then you would have a voltage of <= 0.8 V or >= 4.5V Other voltages might indicate a clock signal but it says nothing about the wave form and frequency. So it is a rough check. Roland The voltage on pin 33 of the 6847 IC...
by John Ferguson
Sat Apr 25, 2020 1:50 pm
Forum: acorn atom and acorn system series
Topic: Another Atom acquired not working
Replies: 23
Views: 716

Re: Another Atom acquired not working

You can also check the voltage of the clock signal. If there's no clock at all then you would have a voltage of <= 0.8 V or >= 4.5V Other voltages might indicate a clock signal but it says nothing about the wave form and frequency. So it is a rough check. Roland The voltage on pin 33 of the 6847 IC...
by John Ferguson
Thu Apr 23, 2020 4:41 pm
Forum: acorn atom and acorn system series
Topic: Another Atom acquired not working
Replies: 23
Views: 716

Re: Another Atom acquired not working

You can check the clock on pin 33 of the 6847. The should be a 3.58MHz square wave. If that's not there then IC9 or the crystal might be broken. Roland I have replaced the crystals for the processor and video IC’s but I still have no display. I am not able to check the clock pin as I do not have th...
by John Ferguson
Mon Apr 20, 2020 11:56 am
Forum: acorn atom and acorn system series
Topic: Another Atom acquired not working
Replies: 23
Views: 716

Re: Another Atom acquired not working

Roland I have replaced C4 and shorted out the 1Mh choke to no visible effect. The modulator produces a signal but there is no monitor output. I have checked all the connections to the crystal circuit for the video chip. The 6847 chip appears to have no output despite installing the one from the work...
by John Ferguson
Sat Apr 18, 2020 3:40 pm
Forum: acorn atom and acorn system series
Topic: Another Atom acquired not working
Replies: 23
Views: 716

Re: Another Atom acquired not working

Thanks Roland for the explanation.

John
by John Ferguson
Sat Apr 18, 2020 12:43 pm
Forum: acorn atom and acorn system series
Topic: Another Atom acquired not working
Replies: 23
Views: 716

Re: Another Atom acquired not working

When talking about the choke you say a shortcut as well. Can you explain this please?

John
by John Ferguson
Sat Apr 18, 2020 11:14 am
Forum: acorn atom and acorn system series
Topic: Another Atom acquired not working
Replies: 23
Views: 716

Another Atom acquired not working

I have acquired another Atom for my collection which is not working as often is the case. I have carried out all the tests as advised previously for the other Atom. All the connections and voltages are correct. And all the chips from a working Atom have been installed. I renewed Q1 and Q2 as there w...
by John Ferguson
Mon Apr 13, 2020 11:37 am
Forum: acorn atom and acorn system series
Topic: Atom just acquired not working
Replies: 53
Views: 1471

Re: Atom just acquired not working

Some photos as requested. The laptop was used to load the programme.

John
20200413_111106_resized.jpg
20200413_111044_resized.jpg
by John Ferguson
Mon Apr 13, 2020 11:23 am
Forum: acorn atom and acorn system series
Topic: Atom just acquired not working
Replies: 53
Views: 1471

Re: Atom just acquired not working

What Mark said... :-D (Y) Perhaps some nice pics please ?... 8) Greetings, Wim... :-) What photos have you in mind? John Hi John, the most usual one Atom + monitor pic,, something like this... :D Greetings, Wim... :-) Thanks in advance... Here is a photo as requested. John 20200413_112026.jpg
by John Ferguson
Sun Apr 12, 2020 3:45 pm
Forum: acorn atom and acorn system series
Topic: Atom just acquired not working
Replies: 53
Views: 1471

Re: Atom just acquired not working

Multiwizard wrote:
Sun Apr 12, 2020 2:09 pm
1024MAK wrote:
Sun Apr 12, 2020 1:31 pm
8)

Well done! 👍 :D

Mark
What Mark said... :-D (Y)

Perhaps some nice pics please ?... 8)


Greetings, Wim... :-)
What photos have you in mind?

John
by John Ferguson
Sun Apr 12, 2020 12:40 pm
Forum: acorn atom and acorn system series
Topic: Atom just acquired not working
Replies: 53
Views: 1471

Re: Atom just acquired not working

John Ferguson wrote:
Sun Apr 12, 2020 10:37 am
Will do Dave.

Thanks
Dave
I can’t thank you enough. The soldering cured the break, delete, repeat, and 5 keys. So simple when you know how.

A full working Atom. I have learnt that the connections such as soldering were not a problem and all the main working IC’s were okay.

John
by John Ferguson
Sun Apr 12, 2020 10:37 am
Forum: acorn atom and acorn system series
Topic: Atom just acquired not working
Replies: 53
Views: 1471

Re: Atom just acquired not working

Will do Dave.

Thanks
by John Ferguson
Sun Apr 12, 2020 7:30 am
Forum: acorn atom and acorn system series
Topic: Atom just acquired not working
Replies: 53
Views: 1471

Re: Atom just acquired not working

Great news John .... You can find some info about repairing here: https://stardot.org.uk/forums/viewtopic.php?f=44&t=18975&p=264101&hilit=Broken+key#p264101 https://stardot.org.uk/forums/viewtopic.php?f=44&t=18327&p=254721&hilit=Broken+key#p254721 https://stardot.org.uk/forums/viewtopic.php?f=44&t=...
by John Ferguson
Sat Apr 11, 2020 5:35 pm
Forum: acorn atom and acorn system series
Topic: Atom just acquired not working
Replies: 53
Views: 1471

Re: Atom just acquired not working

John, maybe you can better work the other way around .... put the chips of the non working Atom an test them in your working Atom. Greetings Kees I have the chips from the working atom in the non working one except for the ram chips. So I will add these ram chips. If this was successful I could the...
by John Ferguson
Fri Apr 10, 2020 5:01 pm
Forum: acorn atom and acorn system series
Topic: Atom just acquired not working
Replies: 53
Views: 1471

Re: Atom just acquired not working

John, maybe you can better work the other way around .... put the chips of the non working Atom an test them in your working Atom. Greetings Kees I have the chips from the working atom in the non working one except for the ram chips. So I will add these ram chips. If this was successful I could the...

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