Commodore 3022 Printer

[ortek_service]

Originally Posted by ortek_service

>>

EDIT: I've just found a copy of the original (50 page) 2022/2023 User Manual: http://www.zimmers.net/anonftp/pub/c...ter-Manual.pdf

And, as well as showing / explaining the different 2022 / 2023 models, and which is tractor feed, it also describes the ribbon
- Which has a tension sensing auto-reverse system, that typewriters did also use. So is rated to last 2 million characters (like endless loop cartridges were)

Reading through the user manual, it states that 'Underwood' type spools are used, which I presume was a standard size / sizes?
And places (Inc. UK company I'd previous found) on Amazion (MarketPlace) are selling Underwood Red/Black typewriter ribbons for round £4.

I also note that the manual mentions the 'reverse' (negative image) printing of characters, but says you shouldn't print more than 5 in sequence, else the print head will be damaged! So it seems there wasn't much heatsink on the print-head & graphics / screen printing with mostly-black background wasn't really possible (Although it doesn't look to have a true bit-map mode - only being able to print standard 'PETSCII' / 1 User-defined character).

It does also seem that on the 3022 tractor-feed version, you can program the line-spacing. Whereas on the 3023 Friction feed version it is fixed. So I guess that's what the link to choose between these, mainly does so that Firmware knows the model.

[ScottishColin]

Not got anywhere near the printer today, but if that ROM needs replacing, it's a 40-pin device and my programmer can't program them...

Colin.

Originally Posted by ortek_service

Yes, the '901472-03' out of the three 901472-0x files there, matches the number that is on the 2332 ROM fitted to yours, I'd found from the photo you'd earlier posted. So you should be able to read yours, as a 2532 EPROM, if your programmer supports those
- or as a 2732 with a pins 18 & 21 swap adaptor: https://wereallgeeks.wordpress.com/2...2_progadapter/

Even though Zimmers (incorrectly?) describe the 901472-03 as being CBM 2023 Firmware
- With 901472-06 described as being CBM 3022 firmware
And also 901472-04 described as being CBM 2022 AND 2023 firmware
(Well this 2022/203 Service Guide, does list the '6332' (But 2332 on both Commodore and Epson board schematics) ROM as being part no. 901472-04

And I did compare those 3 versions, and there are quite a few bytes different. Which would imply that the 3022 wasn't quite just a re-badged of the 2022, and there are ROM differences that may affect compatibility with some 2000-etc. series PET's. Although, luckily it seems your 3022 was untended to work with the 3016 PET.

But reading-out yours may be a useful quick-check, to ensure that reads-OK at least, once reset issue is sorted.

Hopefully the heads smoking a bit was only some dust etc. burning-off due to overheating as not designed to be permanently driven on . And none of the coils have burnt-out. But it should be possible to do a quick low-resistance range on DMM 'cold-resistance' check on all 7? head-coils, once the cable is disconnected, to ensure they all read about the same and none have gone o/c or maybe shorted turns.


I also spotted that the 6532 'RIOT' IC's are confusingly marked with a custom CO10750-12 part number and don't have the 6532 they are more-commonly known as (or 901458-01 Commodore parts-list number). I do recall that COnnnnn numbers were used by Atari, who also used 'RIOT' IC's, so maybe these were stock originally made for them.

[ScottishColin]

OK - print head off and cable removed. Power on and no movement of the roller, but 7B is still out.

7B is a 40 pin IC and is marked as C010750-12. On the underside it is marked as a 6532.

Colin.

[Mark1960]

6532 is RIOT, ram, i/o, timer, not programmable memory.

[TonyDuell]

A couple more comments...

The ribbon had little studs/eyelets near the end to trip the autoreverse mechanism (some typewriters do this too). The epson manual describes the reversing mechanism and how to take it apart.

You want to get those PCB screws out, you are going to want to get to the solder side. Incidentally, can you get the mechanism out? If so, then I'd remove the complete ribbon drive unit at this point (it's only 3 screws, one of which is the clamp for the printhead flexiprint) to make it easier to remove the printhead.

And you're not going to believe this, but I've checked my spares stock and it seems I have a TX80 printhead. It may well be the one with the broken pin that came from my 2023, but the solenoid unit would be good. I might consider exchanging it for your dead one if need be.

[SiriusHardware]

if that ROM needs replacing, it's a 40-pin device and my programmer can't program them...

The ROM is the smaller IC, upper left corner of the PCB, with the number "2332" screen printed next to it. Depending on how the CS pins were defined during the mask programming setup, you may be able to read it directly in your programmer or you may need an adaptor to hold one or more of the CS pins in the correct state for reading.

We'll need to look at the CS pins of the ROM on the circuit diagram to work out what needs to be done in that respect. Edit: I see Owen has already done the research and it should be readable as a 2532.

As has been mentioned the 6532s are 'swiss army' chips, they contain a bit of RAM, a timer and an I/O port device all in one package.

[SiriusHardware]

Tony, would it be possible for you to measure the resistances of the solenoid coils on your TX80 head? If Colin then makes the same measurement on his that may give us some idea of the state of his solenoid coils.

[SiriusHardware]

Regarding the RIOT ICs, I had a quick look around to see if anyone has made a tester project for these. Here is one commercially available product, but while I respect the development time which would have gone into it, I feel it is overpriced given the limited number of devices it tests.

https://www.pinballsolutions.eu/prod...a-riot-tester/

It would theoretically be possible to make a 6532 tester with an Arduino Mega and a datasheet for the 6532. It would not be an absolutely trivial task, this ongoing forum thread gives some idea of the process.

http://forum.6502.org/viewtopic.php?t=7678

[ScottishColin]

I have loaded the contents of the 2332 and it compares correctly with the file 901472-03.bin from Zimmers.

Colin.

[ScottishColin]

Thanks Tony - that's very kind. I'm hoping I haven't done a bad thing to the print head; I guess we'll see though.

Colin.

Originally Posted by TonyDuell

A couple more comments...

The ribbon had little studs/eyelets near the end to trip the autoreverse mechanism (some typewriters do this too). The epson manual describes the reversing mechanism and how to take it apart.

You want to get those PCB screws out, you are going to want to get to the solder side. Incidentally, can you get the mechanism out? If so, then I'd remove the complete ribbon drive unit at this point (it's only 3 screws, one of which is the clamp for the printhead flexiprint) to make it easier to remove the printhead.

And you're not going to believe this, but I've checked my spares stock and it seems I have a TX80 printhead. It may well be the one with the broken pin that came from my 2023, but the solenoid unit would be good. I might consider exchanging it for your dead one if need be.

[ScottishColin]

Motherboard is now free for easier testing.

Colin.

[SiriusHardware]

When you took 7B out it allowed the voltage on the 7B pin 25 receptacle to come up, most likely letting the system come up out of reset. Can you put 7B in a breadboard (or any other anti-skid solution of your choice) and measure the resistance between its VCC pin (20) and pin 7 of 7B.

The voltages we previously measured on the IFC / 7B (7) / 4B (5) node seemed higher than they ought to be, given that the voltage divider on the IFC line should hold that line at roughly two thirds of 5V in the absence of any other signal to drive it low or high.

[ScottishColin]

It is infinite.

I tested the other 6532 and get 5MΩ.

Colin.

[SiriusHardware]

Assuming the printhead etc are still disconnected, can you put 7B back in with pin 25 disconnected from the socket, but all other pins in place. You can either gently bend out pin 25 of the RIOT before placing it in the socket, or if you have a spare conventional 40-pin socket, remove the pin 25 contact from the spare socket, put the RIOT into that and put the RIOT and modified socket into the 7B socket.

However you do it, then power up the board and measure the voltage on 4B(6).

This is to find out whether it is the IRQ pin of the RIOT which is holding the board in reset.

[ScottishColin]

4.97V.

Colin.

Originally Posted by SiriusHardware

Assuming the printhead etc are still disconnected, can you put 7B back in with pin 25 disconnected from the socket, but all other pins in place. You can either gently bend out pin 25 of the RIOT before placing it in the socket, or if you have a spare conventional 40-pin socket, remove the pin 25 contact from the spare socket, put the RIOT into that and put the RIOT and modified socket into the 7B socket.

However you do it, then power up the board and measure the voltage on 4B(6).

This is to find out whether it is the IRQ pin of the RIOT which is holding the board in reset.

[SiriusHardware]

Still with that same setup in place, what voltage do you now have on the main RESET line of the system (for example on the RES pin (pin 1) of the 6504?)

[ScottishColin]

Again, 4.97V.

Colin.

Originally Posted by SiriusHardware

Still with that same setup in place, what voltage do you now have on the main RESET line of the system (for example on the RES pin (pin 1) of the 6504?)

[SiriusHardware]

OK, so lifting the IRQ pin of the 7B RIOT allows the system to come up out of reset.

I believe both 6532s are socketed, what happens to the voltage on 4B (6) when you place the other 6532 in 7B's socket with all of its pins connected? Before moving them around, make sure to mark them in some way so we always know which IC came from which socket originally.

[ScottishColin]

I moved the other 6532 into 7B and left the orignal 7B out of the motherboard - i.e. 5B was empty - 4.98V.

Colin.

Originally Posted by SiriusHardware

OK, so lifting the IRQ pin of the 7B RIOT allows the system to come up out of reset.

I believe both 6532s are socketed, what happens to the voltage on 4B (6) when you place the other 6532 in 7B's socket with all of its pins connected? Before moving them around, make sure to mark them in some way so we always know which IC came from which socket originally.

[SiriusHardware]

Try that again but with the 7B RIOT now fitted (all pins connected) temporarily in the 5B position. Leave the IC originally from 5B in the 7B socket and look again at what happens to the system RESET line.