Oric 1 and Atmos - repair help needed - EDIT: Oric 1 works

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

Post by Steve M » Thu Feb 16, 2017 1:52 pm

If you mean the boot up screen that is supposed to be from the ram chips IIRC

I think only the original type will produce the nice blocks of B&W. Other chips produce vertical lines or horizontal pattern. Don't read too much into the initial boot screen. I've got numerous Orics that produce numerous patterns. and yet they all boot up OK.

Do the checks and try changing that reset capacitor. Check the timers.

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

Post by Steve M » Thu Feb 16, 2017 4:57 pm


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

Post by YuT666 » Thu Feb 16, 2017 5:30 pm

Thanks, i know all these repair pages.

I replaced the C8 & C21 capacitors with new ones and piggy backed all rams ... still the same issue. None of the rams is getting hot.

Maybe i should desolder the via 6522 ... if there is a chance, that this wanker will cause the error.

And what about IC8, IC20 and IC21? They are not known for causing such failures?

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

Post by Chema » Thu Feb 16, 2017 7:34 pm

About the smaller ICs 8, 21,... , anything interfacing with the memory may cause the computer to hang if if fails, but I've never heard of an Oric with such failure alone. The 6522 and the ULA also may cause this. The ULA has a good probability of being ok as you have an image, but who knows... The 6522... I wonder if you could somehow disable it. Maybe setting the CS pin, accessible in the expansion bus as IOCONTROL, to low, or by unconecting the Vcc pin. The Oric should boot, almost. At least to point where IRQs are expected.

I doubt the sound chip may be the cause, as it is interfaced through the VIA and used for sound, of course, and reading the keyboard.

Pity al the involved chips are soldered!

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

Post by YuT666 » Thu Feb 16, 2017 8:33 pm

I think, replacing the via would be a possibility. If there's still the same prob after the replacement ... it turns out to be more difficult.

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

Post by YuT666 » Thu Feb 16, 2017 10:41 pm

So ... i socketed a new via and this crap still has the same issue ... after that i fu**ed up the new one, 'cause i pulled him out in an angry way ... my fault.

Well, i replaced the cpu, the 6522 & the capacitors. What remains? The rams are all only warm and i get similar results when i measured them.

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

Post by Steve M » Fri Feb 17, 2017 11:50 am

My RAM chips don't feel warm. As these chips tend to want replacing and you seem to have spares it might be worth removing them and fitting sockets and putting a fresh set in.
Did you go through the test procedure here? http://oric.signal11.org.uk/html/repairguide.htm

If the 6502 and 6522 are OK and the RAM have been changed (!) then there is the 74ls04 and 74ls257 that can sometimes throw up some odd errors, but to me it looks like one of the main chips that is at fault. Check for broken tracks .

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

Post by YuT666 » Fri Feb 17, 2017 1:24 pm

Thanks Steve ...

So i want to check the RAMs again (each) ... what should i measure here exactly?

One more question: NMI pin 6 (6502) goes directly to?

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

Post by Chema » Fri Feb 17, 2017 8:11 pm

About the NMI in the 6502 it goes directly to the reset button. Nothing else. Check the schematics here (in two parts):
http://oric.free.fr/hardware.html

Again, if you could use the LA on the address bus signals during boot (just a few cycles) it could give us more hints... if not those, the data bus signals. I could calculate the values that should appear, if you are interested.

About the RAM chips, you see that people who repair these old computers usually desolder all of them, put sockets and substitute chips as a first step. It seems to be a common problem. I wouldn't dare to do anything similar.... I am too dumb and dangerous using a soldering iron
:(

Why don't you check continuity of the address and data lines between the 6502 and the memories? That should be easy to do and may be worth checking...

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

Post by YuT666 » Fri Feb 17, 2017 8:56 pm

Well, i'm not very familiar with measuring those stuff. I would say, that i find this really quite dreadful.

So i've to measure all of these adresse and data lines ... but i don't know, what should be good results.

And RAMs A0 - A7 with CPUs A0 - A7 ... and Data in & Data out (CPU). Sorry, but that's not my stuff.

Image

Image

Maybe it's better to send this crap to an Oric repair service in the UK before i hack this one to pieces.

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

Post by Chema » Fri Feb 17, 2017 9:14 pm

What's the fun if there is no challenge? If you finally measure the address lines for a few cycles, post the pic here.

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

Post by YuT666 » Fri Feb 17, 2017 10:38 pm

This challenge isn't that funny ...

Thanks for your help, but i'll don't try more. It only makes me angry. Angry as hell. The Oric 1 works, so who cares ... i don't have a cumulus (seems to be sold out and i sent godzil 2 pms without an answer .. strange, 'cause i asked in a very polite way - but some gods are not willing to give an answer to the ordinary people) or other newer mass storage solutions, so it is completely senseless and there is no reason to sell my soul for this.

Please close & thanks again for your help guys.

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

Post by Chema » Sat Feb 18, 2017 9:42 am

Okay. Sorry for not being more helpful. The best idea, then, is converting your 1 in an Atmos, by putting the 1.1 rom, changing or adapting the keyboard connector, and using the Atmos case. The other would be good for replacements.

About mass storage solutions, I would not expect a new cumulus anytime soon. Godzil is usually very active and responsive, but I guess he is quite busy now.

Best option is Silicebit controller, but he is also too busy now, so doesn't come here often. I heard he had some trouble with components imported from China not arriving or having delays of months. But I am sure he will mount the controllers as soon as he can.

Just keep connected to this forum to exchange experiences and keeping up to date with new productions!

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

Post by Dbug » Sat Feb 18, 2017 12:27 pm

Converting the Oric 1 to Atmos is indeed a good suggestion.
Just move the Oric 1 motherboard in the Atmos case and swap the ROMS.

Done :)

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

Post by Steve M » Sat Feb 18, 2017 12:41 pm

Here's an option. http://www.mutant-caterpillar.co.uk/sho ... kut3oomn43

Only £35 to fix an Oric. Seems like a good deal. The amount of time you can spend and the amount you pay for spare chips, it seems like the best option. Bring the Oric back to life.

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