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Oric Atmos Boot-Up Query

Posted: Thu Jul 26, 2018 10:23 am
by Vyper68
Hi
I have a new Atmos i have just bought and overall it seems in good condition. It needed some TLC though on closer inspection. The PSU Socket was very loose and i needed to replace it. Some of the keys were non-working or very intermittent. That turned out to be one key had contacts that were not closing and completing the circuit i managed to fix that. The other keys were down to bad solder connections. I replaced all the solder connections on the keyboard ( keyswitches only - not entire PCB ) and that fixed those problems.

The other problem is not something i have come across before - on boot up the Atmos has a random character where the cursor would be and the cursor is one character to the right - so it is printing one random character.

Does anyone have any idea what that could be caused by?

The only other thing i have done is replaced the electrolytic capacitors but the problem was there before i did all the repairs.

Re: Oric Atmos Boot-Up Query

Posted: Thu Jul 26, 2018 10:48 am
by Symoon
Vyper68 wrote:
Thu Jul 26, 2018 10:23 am
on boot up the Atmos has a random character where the cursor would be and the cursor is one character to the right - so it is printing one random character.

Does anyone have any idea what that could be caused by?
I also have this "feature" on several Atmos.
I can't remember exactly but I think it is something like the RAM byte that holds "the key that has just been pressed" is randomly initialized - that depending on the garbage on screen you can see for 1 or 2 seconds when booting the Oric.

IIRC this also happened in certain conditions with Euphoric (when double-clicking on a TAP file), according to the "RAM Pattern" parameter chosen for the boot.

I don't know (or don't remember!) why some Orics have random garbage on screen when booting, and why other always have the same, nice "picture". I'd be curious to know!

Re: Oric Atmos Boot-Up Query

Posted: Thu Jul 26, 2018 12:50 pm
by Vyper68
This one has a multi-coloured block random pattern a bit like the ZX Spectrum then it goes to a page of black & white vertical lines and then the Oric welcome screen ( plus "{" 90% of the time ).

It does seem to take a bit longer to boot than my old Atmos ( unless my mind is playing tricks on me ). I am pleased that it seems to be a known "quirk" and not a indicator of a problem. :)

Re: Oric Atmos Boot-Up Query

Posted: Sat Jul 28, 2018 10:12 am
by iss
You're not alone! :)
And I think I have one more Atmos with the same issue.
I don't know why this really happens, but it's interesting for investigation.


Re: Oric Atmos Boot-Up Query

Posted: Sat Jul 28, 2018 10:38 am
by Symoon
On my very 1st Oric-1, I always have this nice and clean boot screen:
Screen88.gif
Screen88.gif (1.65 KiB) Viewed 610 times
... And never any character after "Ready".
But on most of my other machines, I get random garbage - and the random character.

Re: Oric Atmos Boot-Up Query

Posted: Sat Jul 28, 2018 10:42 am
by Dbug
All the time using the same powerbrick, or have you tried with different ones?

I know that one of my Atmos was booting differently depending of which power brick I used.

Re: Oric Atmos Boot-Up Query

Posted: Sat Jul 28, 2018 11:01 am
by Symoon
(not sure the question was for me but anyway ;) ) always got the "clean" boot screen with various PSU, even with disk drive IIRC.

I'm currently digging my emails, because I now recall the Euphoric issue: with Ram patterns 0 and 1, when double-clicking on a TAP file to load it automatically, Euphoric thinks a key has been pressed (just like our real Orics above), and the games asking "pess a key" to start were starting automatically! This didn't happen with Ram Pattern 2 (the "clean" one).
Ram patterns parameter in Euphoric is a great way to see if a game made on emulator initializes correctly its variables (happened with O-Thrust a while ago, remember?)

Anyway I found back a 1st mail, Fabrice saying (rough translation):
"In Euphoric the Ram pattern was a drawing until I understood the mapping with rams polarity. It is now representing the rams content when the Oric is powered."
"some Orics have 8 ram chips, each one holding a bit from a byte; others have 2 chips, each on holding 4 bits".
So it depends on ram chips types, and their amount apparently! Doesn't explain in detail the garbage, but that's a start.

Re: Oric Atmos Boot-Up Query

Posted: Sat Jul 28, 2018 4:31 pm
by Vyper68
Well my Atmos has 8 4164 stylye RAM Chips.

Image

Re: Oric Atmos Boot-Up Query

Posted: Sat Jul 28, 2018 4:33 pm
by Vyper68
iss wrote:
Sat Jul 28, 2018 10:12 am
You're not alone! :)
And I think I have one more Atmos with the same issue.
I don't know why this really happens, but it's interesting for investigation.

I get the same character as you most of the time - this is very odd.

Re: Oric Atmos Boot-Up Query

Posted: Tue Aug 07, 2018 10:14 am
by ibisum
I have 8 Atmos, an Oric-1 and a Telestrat - and they all behave differently depending on the power supply being used. I've noticed that the lower Amps, the messier the screen on boot up - maybe this is a clue?

Re: Oric Atmos Boot-Up Query

Posted: Thu Aug 09, 2018 3:19 pm
by Vyper68
ibisum wrote:
Tue Aug 07, 2018 10:14 am
I have 8 Atmos, an Oric-1 and a Telestrat - and they all behave differently depending on the power supply being used. I've noticed that the lower Amps, the messier the screen on boot up - maybe this is a clue?
I am using a decent 9V 1A PSU what are you using for your Oric's & Telestrat ( nice :D )