Oric-1 Help Needed

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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iss
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Re: Oric-1 Help Needed

Post by iss »

RetroKrazy wrote: Fri Dec 15, 2023 10:24 pm... I do get a single quote character " printed on screen after a cold reset. Is this normal?
Indeed, it can be count as normal :).
Most often the printed char is the pound sign £ but can be any one - no rule here.
The source of the problem is unknown but it's most probably related to power.
You can try:
- another classic power brick or decent switching PSU 9V;
- a good 5V power source attached after the 7905 (i.e. directly to the VCC and GND tracks);
- add pull-up resistor 1k ... 10k (value is not critical) as shown on the pic:
Screenshot_20231216_021632.jpg
RetroKrazy
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Re: Oric-1 Help Needed

Post by RetroKrazy »

Well, she lives! Full battery of tests and she passed them all. Even tape loading (well, off a SVI-CAS :D ) and no problems so thank you all for the help!
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Dbug
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Re: Oric-1 Help Needed

Post by Dbug »

Great to hear :)
Now the question is: Do you know what actually was the things that fixed it :D
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Re: Oric-1 Help Needed

Post by RetroKrazy »

Yes, swapping the 4864 memory out for the 4164 - memory issue as that was the only change before she properly sprang to life! I need a better tester that can check the 4864 to find out which of them is faulty though.
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iss
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Re: Oric-1 Help Needed

Post by iss »

RetroKrazy wrote: Sun Dec 17, 2023 4:50 pmI need a better tester that can check the 4864 to find out which of them is faulty though.
Why not DRAMARDUINO? :D
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Re: Oric-1 Help Needed

Post by RetroKrazy »

Sorry I've not been on for a bit. RL got in the way and my wife was hospitalised.

Happy New Year all and TY to all for the very helpful feedback! I have a small YT channel and thought it only fair I share here too, though please dbug, delete this post or move it if it breaches any forum rules.

This was 3 weeks of corrupted file recovery (almost 75% of the files were corrupted and lost a few) plus editing to get to this stage.



and iss, does it do 4864 as only lists 4164 and 41256 unless I missed something?
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iss
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Re: Oric-1 Help Needed

Post by iss »

RetroKrazy wrote: Fri Jan 05, 2024 10:22 pmdoes it do 4864 as only lists 4164 and 41256 unless I missed something?
Yes, it can test any 64K x 1bit, including 4864.
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Re: Oric-1 Help Needed

Post by kenneth »

@RetroKrazy
Nice repair ! 8)
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Re: Oric-1 Help Needed

Post by Chema »

Great repair! Congratulations!
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Re: Oric-1 Help Needed

Post by Jonh »

Great stuff, RK!

BTW, you can break out of unprotected Basic programs with CTRL-C
You can also usually prevent autorun on an unprotected Basic or M/C program with CLOAD"",N

Enjoy!
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Re: Oric-1 Help Needed

Post by RetroKrazy »

Jonh wrote: Sun Jan 07, 2024 2:17 am BTW, you can break out of unprotected Basic programs with CTRL-C
You can also usually prevent autorun on an unprotected Basic or M/C program with CLOAD"",N
Thanks, good to know!
iss wrote: Sat Jan 06, 2024 1:27 am Yes, it can test any 64K x 1bit, including 4864.
Looks like I have a project to test those 4864s then :D
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Re: Oric-1 Help Needed

Post by RetroKrazy »

A viewer spotted that there appears to be two caps missing, one to the left of C14 and between C18 and C20 right below the RAM. I'm guessing as there is no screen print on the board with those designators, the spaces are unpopulated and I don't see them on the schematic around the RAM ICs, they aren't necessary?
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iss
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Re: Oric-1 Help Needed

Post by iss »

RetroKrazy wrote: Tue Jan 09, 2024 5:01 pm...the spaces are unpopulated and I don't see them on the schematic around the RAM ICs, they aren't necessary?
Indeed, they are factory unpopulated, may be the reason is mechanical (i.e. better fitting in the case).
20240109_181236.jpg
Else, the CAPs are just decoupling ones and I normally replace them with smaller sized 47nf or 100nf.
You can try to solder both hoping to minimize the ripples in VCC, which actually can be the source for the issue.
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Re: Oric-1 Help Needed

Post by RetroKrazy »

iss wrote: Tue Jan 09, 2024 5:23 pm Indeed, they are factory unpopulated, may be the reason is mechanical (i.e. better fitting in the case).
Could also be a little bit of money saving as otherwise it works well :)
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