Atmos 48k broken, doing strange things

If you want to ask questions about how the machine works, peculiar details, the differences between models, here it is !
How to program the oric hardware (VIA, FDC, ...) is also welcome.
dj_pirtu
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Atmos 48k broken, doing strange things

Post by dj_pirtu »

Hi!

I found my old Atmos 48k from basement and tried it. It worked maybe few minutes like normal but then it failed. It does not boot sometimes at all, just shows the weird blocks on the screen. And when it gets to basic it shows only 11kb of memory, makes 'B' letters on the screen, does that 'ping' sound randomly and when try to write something it crashes immediately.

First seven memory chips are warmer than the last one, not hot actually. Already bought new 4164-chips and I'll try to change them. Could there be something else wrong? I really want to fix this, it's so rare machine...

Image
Oric Atmos 48k
dj_pirtu
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Post by dj_pirtu »

Ok, now I found this:

http://www.nbl.fi/~nbl2192/retro/20100903_003.jpg

It was in connection with third leg from corner in IC6. Lifted it up, didn't help...

Damn, don't have oscilloscope. With that and service manual this could much easier...
Oric Atmos 48k
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Dbug
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Post by Dbug »

At least you know that most of the important components are working:
- Cpu works
- Soundchip is working fine
- VIA as well (else you would not have keyboard and sound)
- Most of the memory for sure (since you have page 0 and screen working)

I know the service manual was available somewhere, I seem to remember that Steve Marshall had a version online somewhere.

There's also a diagnostic rom/cartridge somewhere that helps testing this kind of thing.
JamesD
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Post by JamesD »

Is there a short on the B key?
dj_pirtu
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Post by dj_pirtu »

JamesD wrote:Is there a short on the B key?
No, it does that even if keyboard isn't connected.
Oric Atmos 48k
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