Hello,
Recently I bought Oric Atmos off eBay as "not tested". Upon powering on it greets me with a typical black-white RAM failure screen.
I would simply replace RAM chips, as many cases described before me, but it comes also with some humming noise from the speaker, so I suspect there is something else to replace. Any suggestions or advices please?
A similar post was about affected 6502, so I am afraid it would be not that simple
https://forum.defence-force.org/viewtop ... 7&start=45
In the meanwhile my picture is close or similar to this case (RAM failure)
https://forum.defence-force.org/viewtop ... f=8&t=2029
Cheers
PS cannot burn test ROM atm
Atmos RAM failure? Need help
Re: Atmos RAM failure? Need help
Alright since none was interested I began to actually repair it
Few chips were already socketed, so I removed only soldered ones
Then a clean with ISP, just in case. All holes were checked with the pin, all tracers were buzzed for continuity. 4 sockets installed and filled with Russian RAM chips, borrowed from my Pentagon 128
After powering up the noise described above was present but in a matter of 1.5-2 seconds it became significantly silent, and I was greeted by booted machine A flawless victory!
Next step is a proper SD solution and SCART cable
Still that noise is very annoying, any tips to make it silent? Or it is an Atmos feature - never had an Oric before.
Any ideas or hints?
Few chips were already socketed, so I removed only soldered ones
Then a clean with ISP, just in case. All holes were checked with the pin, all tracers were buzzed for continuity. 4 sockets installed and filled with Russian RAM chips, borrowed from my Pentagon 128
After powering up the noise described above was present but in a matter of 1.5-2 seconds it became significantly silent, and I was greeted by booted machine A flawless victory!
Next step is a proper SD solution and SCART cable
Still that noise is very annoying, any tips to make it silent? Or it is an Atmos feature - never had an Oric before.
Any ideas or hints?
Re: Atmos RAM failure? Need help
Alright, reading suggest it is a feature, and it sounds exactly like this
http://www.mirari.fr/ZobC?a=open
So I should replace C1, C8 and C21 just to be sure
http://www.mirari.fr/ZobC?a=open
So I should replace C1, C8 and C21 just to be sure
Re: Atmos RAM failure? Need help
I was about to suggest you replace RAM and the RAM multiplexers. Those are nearly always the culprits with such symptoms. You simply were too fast