Two dead Atoms! Life Support possible?

emulators, hardware and classic software for atom + system machines
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Mel_P
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Two dead Atoms! Life Support possible?

Post by Mel_P » Wed Feb 12, 2020 12:01 pm

Well Mark has just taken my dead beeb and lots of stuff and I'm hoping in return for charity donations.

Talking to a friend about dead relics (!) he has 2 "dead" (i.e. non-responsive) Atoms that he built yesteryear and spent happy hours with. They became a "group property" in a computer club and he subsequently had them back in store. He dug them out recently and they were DOA.

I have checked both power supplies and they are both about 11vDC "no load". When plugged in both atoms "get warm" and the power supply heat sink gets fairly warm but there is no sign of life, no beep, no UHF signal etc. Each board has a supply rail of ~5V so power seems ok.

They seem a lost cause! is there some simple check (V, no scope available) which might give a guide to the fault - or is there some death wish which causes ageing Atoms to fail?

Any guidance please?

Mel_P

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oss003
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Re: Two dead Atoms! Life Support possible?

Post by oss003 » Wed Feb 12, 2020 12:09 pm

Hi Mel,

maybe this is a good start: viewtopic.php?f=44&t=6318&p=60505&hilit ... ion#p60505

Greetings
Kees

Prime
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Re: Two dead Atoms! Life Support possible?

Post by Prime » Wed Feb 12, 2020 1:48 pm

Also a simple test to see if the atom is alive** even if you have a fault in the video circuit is type CTRL-G (hold CTRL down whilst repeatedly pressing G), you should hear it beep.

**Alive in as far as CPU/ROM/RAM working and it's reaching basic.

Cheers.

Phill.

Mel_P
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Re: Two dead Atoms! Life Support possible?

Post by Mel_P » Thu Feb 13, 2020 7:35 pm

Ctrl G test = NO beep

Did try pressing the "Break" key before the Ctrl G test also but this had no effect.

Looks fatal!

Kazzie
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Re: Two dead Atoms! Life Support possible?

Post by Kazzie » Thu Feb 13, 2020 9:46 pm

Oh, I'm pretty sure it's not fatal with an Atom until the PCB is cracked in half! :lol: It's just a matter of how much time and effort you have, and what sort of testing equipment you have available.

Have you tried the steps suggested by Kees (oss003)?
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Multiwizard
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Re: Two dead Atoms! Life Support possible?

Post by Multiwizard » Thu Feb 13, 2020 10:20 pm

Mel_P wrote:
Thu Feb 13, 2020 7:35 pm
Looks fatal!
Belief me almost all Atoms are resurrectable ... :D


Greetings, Wim... :-)

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roland
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Re: Two dead Atoms! Life Support possible?

Post by roland » Thu Feb 13, 2020 10:55 pm

Multiwizard wrote:
Thu Feb 13, 2020 10:20 pm
Belief me almost all Atoms are resurrectable ... :D
Unless you attack them with a grinder :mrgreen:

You mention there is no UHF signal..... IMHO there should be at least a grey screen at channel 36 regardless if the Atom works or not. In the first place I'd strip it to a minimal Atom like Kees suggests and then check every ic for a correct 5V. With the 7805's in place the 5V rails are split in two parts, maybe one is broken....
FPGAtom: 512 KB RAM, Real Time Clock and 64 colours
MAN WOMAN :shock:

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Multiwizard
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Re: Two dead Atoms! Life Support possible?

Post by Multiwizard » Fri Feb 14, 2020 6:08 am

roland wrote:
Thu Feb 13, 2020 10:55 pm
Multiwizard wrote:
Thu Feb 13, 2020 10:20 pm
Belief me almost all Atoms are resurrectable ... :D
Unless you attack them with a grinder :mrgreen:
Oh :shock: who would do something gruesome like that :shock: [-X :^o

A jigsaw maybe... :lol: 8)


Greetings, Wim... :-)

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1024MAK
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Re: Two dead Atoms! Life Support possible?

Post by 1024MAK » Fri Feb 14, 2020 2:25 pm

So, to drag this thread kicking and screaming away from people who cut Atom boards up...

When you press BREAK, press and hold it for one whole second. Then try the Control-G key press.

An unmodified Atom uses TWO 7805 voltage regulators, with each supplying about half of the circuitry. So one test of the +5V is not enough. Check as many chips as possible.

Also, when the PSU is connected to the Atom, what voltage do you get when you test the input voltage with your multimeter?

As said above, even if there is no input video signal to the modulator, it will still produce a ‘carrier’ signal. But with no input, there will be no synchronisation signals. So modern TVs are unlikely to detect it. An old analogue CRT TV will display a different and less noisy image compared to the normal background ‘static’ noise that you get with an ‘empty’ channel.

Apart from a multimeter, what other test equipment do you have, or have access to?

It will be helpful if you can post up some photos of both your Atoms.

Mark

bprosman
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Re: Two dead Atoms! Life Support possible?

Post by bprosman » Fri Feb 14, 2020 2:35 pm

Imho starts with default troubleshooting.

Strip it to the minimum config.
Are all voltages ok ?.
Is the reset circuit ok (level) ?.
Is there a clock in/out the CPU and video processor ?.

If that is all ok I (but I do owe one, so easy to suggest) throw in Dave (Hoglet's) ICE-T65

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oss003
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Re: Two dead Atoms! Life Support possible?

Post by oss003 » Fri Feb 14, 2020 3:03 pm

If the power on the 6502 is +5V and ctrl-g does nothing, try swapping the 6502 with the one in the other system.

Greetings
Kees

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DutchAcorn
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Re: Two dead Atoms! Life Support possible?

Post by DutchAcorn » Fri Feb 14, 2020 7:30 pm

Can you post pictures of the boards? Do the Atoms both still have their speakers?

The RF signal can be a pain to find. You can do a simple video mod to change the output of the RF socket to composite video. See here: https://stardot.org.uk/forums/viewtopi ... 72#p232713
Paul

Image

bprosman
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Re: Two dead Atoms! Life Support possible?

Post by bprosman » Fri Feb 14, 2020 9:04 pm

Actually no mod required, composite video is available on pen 9,10 of PL/4

Mel_P
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Re: Two dead Atoms! Life Support possible?

Post by Mel_P » Wed Feb 19, 2020 10:44 pm

As I said at the beginning, these are not mine. Hence I don't want to fiddle too much and start stripping out chips etc. I have passed the info on to the owner and will let him decide how much he wants to do by way of investigation.

He did ask me to look at his "dead" BBC model b - which with fuses replaced is now very much alive. He may be selling that??

Mel_P

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