Oric-1 Repair

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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Vyper68
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Re: Oric-1 Repair

Post by Vyper68 » Mon May 20, 2019 6:03 pm

Well this is odd, The traces are all OK on the Main and Keyboard PCB...
Left shift does not work for < >
Right Shift does not work for ? * ) + |

So I will have to keep on this one to see if i can find out why. It's working which is the main thing.
Bazinga!

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mikeb
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Re: Oric-1 Repair

Post by mikeb » Mon May 20, 2019 6:08 pm

An odd combination of characters, they seem to be grouped physically (by proximity) rather than by organization in the row-column matrix (see the Service Manual .pdf).

Wait, you got a 10 key? What advanced model of Oric is this? :)

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iss
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Re: Oric-1 Repair

Post by iss » Mon May 20, 2019 6:15 pm

mikeb wrote:
Mon May 20, 2019 6:08 pm
Wait, you got a 10 key? What advanced model of Oric is this? :)
It's obvious '0' :D. Here is the matrix:
kbd.png
kbd.png (125.82 KiB) Viewed 3431 times
The only suspects here are 6522, AY-3-8192 and 4051, maybe the TR2 too...

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Re: Oric-1 Repair

Post by iss » Mon May 20, 2019 6:16 pm

mikeb wrote:
Mon May 20, 2019 6:08 pm
Wait, you got a 10 key? What advanced model of Oric is this? :)
It's obvious '0' :D.
Here is the matrix and the keys are on the same row:
kbd.png
kbd.png (125.82 KiB) Viewed 3428 times
The only suspects here are 6522, AY-3-8192 and 4051, maybe the TR2 too...

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Re: Oric-1 Repair

Post by Vyper68 » Tue May 21, 2019 9:01 am

:D oops 10 Key LOL
Bazinga!

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Re: Oric-1 Repair

Post by mikeb » Tue May 21, 2019 6:14 pm

iss wrote:
Mon May 20, 2019 6:16 pm
Here is the matrix and the keys are on the same row:
They're not in the same row, hence my puzzled comment.

Original posting 7 failed keys: Right: "8 0 - =" and Left: " , . / "

By your picture (which is in a different (more logical order) compared to the service manual) :-

"8,0,/ and =" are in one row (7) aka " * ) ? +"
", ." are in another (4) aka "< >"
"-" is in a third. (3) aka "£"

And new addition "|" aka "\" (also row 3).

How is that the same row?

If it's the entire row, what about k/K, :/; and l/L etc? Do they work?

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Re: Oric-1 Repair

Post by Vyper68 » Wed May 22, 2019 9:20 am

k/K l/L and ;/: work with both shift keys and also Ctrl works as well. It's not a big problem I can work around it, I am just pleased I got it working compared to when it arrived.
Bazinga!

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Re: Oric-1 Repair

Post by Steve M » Sat Aug 10, 2019 4:05 pm

I've got a keyboard with failures of the comma, full stop right and down keys, all on 4 row.
The circuit seems OK so I guess it leaves the keyboard chip as the likely suspect?

I've got an Atmos that boots but it is rather reluctant. It can take 3 or four times plugging in the power supply. I've swapped the C8 and C21 with no change. The chips are mostly socketed so I've swapped 6502, 6522 and RAM and it is still struggling.

Any suggestions? What to try next?

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Re: Oric-1 Repair

Post by Steve M » Sat Aug 10, 2019 4:16 pm

iss wrote:
Mon May 20, 2019 6:15 pm
. Here is the matrix:
kbd.png
I'm trying to follow this. What are the hex numbers referring to? IN the AUG the connector pins are given as 1 2 3 4 12 11 9 5

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Re: Oric-1 Repair

Post by Chema » Sat Aug 10, 2019 7:31 pm

Iirc these are the values you have to set in the AY registers to access each column.

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Re: Oric-1 Repair

Post by mikeb » Sat Aug 10, 2019 7:44 pm

Steve M wrote:
Sat Aug 10, 2019 4:05 pm
I've got an Atmos that boots but it is rather reluctant. It can take 3 or four times plugging in the power supply. I've swapped the C8 and C21 with no change. The chips are mostly socketed so I've swapped 6502, 6522 and RAM and it is still struggling.
When it powers up (but fails to boot), what happens if you manually short P40 and P1 of the 6502 with a wire (~RESET to GND) briefly? Does it then start?

If so, your reset is still not long/hard enough for everything to be working correctly when the 6502 is released from cold boot.

Have you checked the inverter chip used to generate the clock, in case it's not oscillating as well as it used to, and is having trouble getting started? (Leaving the ULA still getting its act together when the reset is already finished?)

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Re: Oric-1 Repair

Post by iss » Sat Aug 10, 2019 8:30 pm

As @Chema said the HEX values represent which column is to be scanned
i.e. if particular bit is '0' then the column is 'activated'.
Here is better picture and how the things work:
OricKbd.jpg
For instance to check if the comma is pressed we set AY I/O register to value #FD - this passes '0' to the entire column, if the 'comma' is pressed the '0' travels to the input pin 1 of 4051, we set bits 0,1,2 of VIA port B to #04 - this routes the '0' on input pin 1 to the output pin 3 and the transistor TR2 inverts the signal to '1', so when we read VIA port B we will have bit 4 set i.e. PB4='1'. That's it! :)

The easiest way to proceed is to replace the keyboard with working one - if everything works then VIA and AY are OK.
You said the entire row is not working - check the track which starts from pin 1 of the 4051.

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Re: Oric-1 Repair

Post by Steve M » Sat Aug 10, 2019 9:40 pm

Thanks - I hadn't thought of the values like that as I just have a separate keyboard to work on.
I'm just trying to check things with a continuity tester and can't find any problems, so I'm suspecting the chip is faulty.


Mike, I'll try that. I'll see if I have a spare inverter to swap. I will have one on another socketed board I could swap over to try at least.

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Re: Oric-1 Repair

Post by Steve M » Mon Aug 12, 2019 12:16 pm

Tickling the 6502 would boot the Atmos. It was still a bit sluggish.
Most of the chips are socketed so I stuck in a different 740ls04 and it boots. Many thanks for the tips !!!

I've found some 4051 chips whilst looking for 74ls04 so I may replace the keyboard chip and see if it sorts things.

(Just for clarity, I don't have an entire row faulty - the 4 keys are on the same row. )

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Re: Oric-1 Repair

Post by Steve M » Tue Aug 13, 2019 3:38 pm

Success!
I swapped the 4051 chip and it works. Another keyboard saved. :))

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