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Re: Oric 1 and Atmos - repair help needed - EDIT: Oric 1 wor

Posted: Mon Feb 13, 2017 5:01 pm
by Chema
Great, congratulations!

Re: Oric 1 and Atmos - repair help needed - EDIT: Oric 1 wor

Posted: Mon Feb 13, 2017 5:10 pm
by YuT666
Thanks ... it is a little bit strange. The cpu was the first component i replaced ... and the Oric is working. It might have been the RAMs or the 6522 or the ULA or or or ...

Re: Oric 1 and Atmos - repair help needed - EDIT: Oric 1 wor

Posted: Mon Feb 13, 2017 5:48 pm
by iss
Great indeed! Congratulation and it's highly probable, that Atmos has the same problem.
Actually it's very easy to burn the CPU when connecting some periphery in wrong way to the expansion port.

Re: Oric 1 and Atmos - repair help needed - EDIT: Oric 1 wor

Posted: Mon Feb 13, 2017 6:57 pm
by Chema
If iss is right (he surely is) the the owner might have tried to plug something in the expansion port and broke the two Orics. I've heard people plugging the PSU into the expansion port by accident. Some even cover the expansion port to avoid damage.

And you've made a good job with the socket! I would've never done the replacement without burning other chips and totally destroying the Oric :)

Re: Oric 1 and Atmos - repair help needed - EDIT: Oric 1 wor

Posted: Mon Feb 13, 2017 7:53 pm
by YuT666
Yes, this could be the problem ... the seller did the same failure with both Orics. I think i'll make a cover for the expansion port too. So i think tomorrow it's time for the Atmos.

Re: Oric 1 and Atmos - repair help needed - EDIT: Oric 1 wor

Posted: Mon Feb 13, 2017 8:45 pm
by Steve M
Great thread. Very interesting.
I've a drawer full of little plastic covers for the expansion port. Let me know if you want a couple - or a hundred.

Re: Oric 1 and Atmos - repair help needed - EDIT: Oric 1 wor

Posted: Mon Feb 13, 2017 9:01 pm
by YuT666
Well, i would take some ... :wink:

And now i should go for a cumulus ... but it's hard get one.

Re: Oric 1 and Atmos - repair help needed - EDIT: Oric 1 wor

Posted: Tue Feb 14, 2017 10:54 am
by YuT666
Atmos:

I desoldered the old cpu and put a socket in. Tried three different cpus and the Atmos still has the same issue (the pattern i showed in the first post). I checked the socket again and again, but that changed nothing. All cpus worked with the Oric 1, so there must be an other problem. Crap.

Re: Oric 1 and Atmos - repair help needed - EDIT: Oric 1 wor

Posted: Tue Feb 14, 2017 12:24 pm
by Chema
Argh!

Did you try piggibacking the memory in the Atmos?

Re: Oric 1 and Atmos - repair help needed - EDIT: Oric 1 wor

Posted: Tue Feb 14, 2017 4:18 pm
by YuT666
Yes, i tried all 8 RAMs ... no change.

Could someone please show me a pic from the bottom side of an issue 4 board? I only have one modification there.

Maybe i should put the V1.1 basic rom into the issue 3 and put the good board in the atmos case, so i have time to repair the issue 4.

Re: Oric 1 and Atmos - repair help needed - EDIT: Oric 1 wor

Posted: Tue Feb 14, 2017 6:09 pm
by iss
Attached are both sides of issue-4, because the "patch" which makes VIA not so hot has a capacitor on the component side (see red arrow).
Else, I have 3x issue-4 without any modifications and they work well, so you decide...
It's good idea to check ROM v.1.1 in issue-3 - this will confirm that it's ok.
20170214_185140-1.jpg
20170214_185156-1.jpg

Re: Oric 1 and Atmos - repair help needed - EDIT: Oric 1 wor

Posted: Tue Feb 14, 2017 7:14 pm
by Steve M
Maybe different issue but this is an interesting read.
http://blog.tynemouthsoftware.co.uk/search/label/Oric

Re: Oric 1 and Atmos - repair help needed - EDIT: Oric 1 wor

Posted: Wed Feb 15, 2017 10:11 pm
by Godzil
If it goes that far, yes probably :) (as most of the important components are use for keyboard/sound/DRAM/video)

Maybe the composite/RF is not working but who care?

Re: Oric 1 and Atmos - repair help needed - EDIT: Oric 1 wor

Posted: Thu Feb 16, 2017 11:45 am
by Chema
Let's first try to repair that Atmos! I am not sure if you made all the checks you did in the Oric-1, such as measuring voltages at main chips, check for ram going too hot, checking the clock and phi2 signals, the RST signal...

Please let us know how far you went in these checks :)

Oh! and, by the way, if you plan to use the Atmos case in the Oric 1, it is NOT just a matter of putting the 1.1 ROM and using the Atmos case, because the keyboard needs a different connector (nearly identical but with longer pins). Not sure if it is easy to put some kind of extension but else you'll have to change it.

Re: Oric 1 and Atmos - repair help needed - EDIT: Oric 1 wor

Posted: Thu Feb 16, 2017 11:55 am
by YuT666
Yes, i did the same checks with nearly the same results. But the Atmos shows an other error pattern (as shown in the first post).

I received a 6522 VIA yesterday, but i don't want to desolder the old one.