Oric-1 Repair
Re: Oric-1 Repair
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.
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.
Oric Extended Basic V1.1
(C) 1983 Tangerine
37631 Bytes Free
(C) 1983 Tangerine
37631 Bytes Free
- mikeb
- Flight Lieutenant
- Posts: 282
- Joined: Wed Sep 05, 2018 8:03 pm
- Location: West Midlands, UK
- Contact:
Re: Oric-1 Repair
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?
Wait, you got a 10 key? What advanced model of Oric is this?
- mikeb
- Flight Lieutenant
- Posts: 282
- Joined: Wed Sep 05, 2018 8:03 pm
- Location: West Midlands, UK
- Contact:
Re: Oric-1 Repair
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?
Re: Oric-1 Repair
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.
Oric Extended Basic V1.1
(C) 1983 Tangerine
37631 Bytes Free
(C) 1983 Tangerine
37631 Bytes Free
Re: Oric-1 Repair
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?
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?
Re: Oric-1 Repair
Iirc these are the values you have to set in the AY registers to access each column.
- mikeb
- Flight Lieutenant
- Posts: 282
- Joined: Wed Sep 05, 2018 8:03 pm
- Location: West Midlands, UK
- Contact:
Re: Oric-1 Repair
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?)
Re: Oric-1 Repair
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: 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.
i.e. if particular bit is '0' then the column is 'activated'.
Here is better picture and how the things work: 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.
Re: Oric-1 Repair
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.
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.
Re: Oric-1 Repair
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. )
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. )
Re: Oric-1 Repair
Success!
I swapped the 4051 chip and it works. Another keyboard saved. )
I swapped the 4051 chip and it works. Another keyboard saved. )