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Atmos : it doesn't start !

Posted: Mon Mar 19, 2018 7:46 pm
by colossusfr
Hi,

I have just found my old Oric Atmos at my parent's home. I bought it in the 80's and I learned a lot from it.
It was in a good storage for all these years.

After buying a new power and a new scart cable, I tried to switch it on. It starts but not with the good screen. Here is what I see :
Image

Is there someone who could help me ? Which component could fail ?

Thanks,
Alain.

Re: Atmos : it doesn't start !

Posted: Mon Mar 19, 2018 7:57 pm
by Dbug
What you can try is to open it, leave it running for a short while and then put your fingers over the ram chips, see if one or more are warmer than the other, that's a common issue.

Re: Atmos : it doesn't start !

Posted: Mon Mar 19, 2018 9:13 pm
by Chema
Yep. Usually suspects are RAM chips. Beware a defective chip may become really hot and you can burn your finger.

At least the computer is booting.

You can also check voltages to see if they are correct in all chips. Gently press the chips that are in sockets, or remove them, clean the contacts and try again.

Also be sure your PSU works correctly.

Re: Atmos : it doesn't start !

Posted: Tue Mar 20, 2018 8:34 am
by colossusfr
Thanks for your reply.

I'll try to check all the RAM.

Alain.

Re: Atmos : it doesn't start !

Posted: Wed Apr 11, 2018 6:41 pm
by Steve M
That looks like it's booting. Do you get key clicks? If you type PING [return] can you hear the sound ?

I suspect a problem with ULA or ROM. Check pins are all connected in any socketed chips.

Re: Atmos : it doesn't start !

Posted: Fri Apr 20, 2018 5:02 am
by NekoNoNiaow
As indicated by Chema, check the voltages of your power supply.
It should be providing +9V to the Oric, which are then regulated internally to +5V.