Commodore 3022 Printer

[TonyDuell]

It is a spool of ribbon, not a cartridge, so there's a good chance you'll be able to get something that will work. I _think_ the Epson TX80 used the same mechanism.

AFAIK, yes, the 2022 is the tractor feed model, the 2023 the friction feed one. There is no sane way to convert one to the other. The link that grounds one of the port pins used to drive the stepper motor in the former model is detected by the firmware at power-up and enables the friction feed solenoid driver routine, etc. So I _think_ the ROM is the same in both models.

Incidentally I was given my 2023 because the bottom pin in the printhead was broken. I did get a replacement printhead in the end but before that I just soldered a jumper on the printhead connector to wire-OR the drivers for the bottom 2 pins. The output was a bit odd, but readable, and a lot better than no printer at all.

[ScottishColin]

Morning. Work meetings at 08:30. Ugh.

From the -other- end of R5 down to ground. Meter on resistance, mains plug inserted but switched off at the socket, black probe on earth, red on R5 - 2.2kΩ

Resistance from 7A (5) to 0V - also 2.2kΩ
Resistance from 7A (10) to 0V - 18.7kΩ

There doesn't seem to be a 6B on this board - I'll annotate the drawing that is in that PDF in a while to try to properly locate everything.

Colin.

Originally Posted by SiriusHardware

Good spot by Mark, I hadn't followed that 5V line far enough to realise that it was switched, however the 5V does seem to be present.

We can disregard the mythical case-open switch because J8, which is connected across it, has been confirmed to be fitted.

For the measurement of C6 I would expect to see a brief flash of low resistance rising to a high resistance - for a 10uF capacitor that would only take a brief moment but you should see that, so I'm not sure we had the right measurement points there or were making proper contact.

One end of R5 should have direct continuity to 7A (5), find out which one that is and then measure from the -other- end of R5 down to ground. Meter on resistance, not on continuity - as you initially put the probes on those points you should see a brief flash of low resistance, rising to a higher resistance. If you don't see that we may need to do a proper check on C6, although an open-circuit C6 would not cause our reset-low problem.

Final suggestions for tonight, with power off, measure the resistances from 7A (5) to 0V, from 7A (10) to 0V, and from 6B (6) to 0V.

[ScottishColin]

I've not looked into these (apart from downloading them just in case) but these seem to be the ROMs:

https://zimmers.net/anonftp/pub/cbm/...022/index.html

Colin.

Originally Posted by ortek_service

I've now also managed to work-out which of the (Both confusingly labelled EPSON, and not sure what the other '3110' label refers to) diagrams applies. As the manual doesn't make it clear what the 2022 and 2023 differences are.
I've also not managed to work out how a 3022 / 3023 differs, other than they are targeted at specific PET model series. And that the PET 2001(N/B) doesn't apparently have print routines built in, and you must have a printer customised or use with either the 2001N or 2001B?
But hopefully any PET 30xx / 40xx model can be used with a 30xx printer.

The only Commodore printers I recall having much experience of was a (Seikosha? based) MPS-801 (Commodore cut-down IEEE-488) 'Serial' one on the C64, where after fitting a new ribbon, the head wasn't returning to start. But this just used a very long coil spring to do this, and a bit of WD-40 freed-up the slightly-sticking mechanism.


Both 2022/2023 manual schematics seem a bit over-complex, having RAM (and timers + I/O) split between two 6532 'RIOT' IC's. And there's a crucial typo that says the ROM is in a 6332 (So easily confused with a 6532 / an RRIOT, with ROM in it), when it is actually (luckily) in a 'standard' 2332 dedicated ROM IC.
Hopefully these are all OK - But at least there are ways of replacing these if the originals are not available
(Assuming there's a copy of the ROM out there on the 'net, if it unfortunately ever fails / to verify it is still OK)

It seems to me that nIRQ (which is also a feed into their reset circuit) is driven by a (OR) gate of '4B' (Is there a table anyway to translate these PCB positions to real part numbers? - As seems to be lacking on the schematic / 'Cross-Reference' parts list / B.O.M) which is driven by an 'IFC' line from the IEEE-488 port connector (Pin 9), that is Pulled-high with 3k3 and pulled low with 6k8 'termination' resistor networks.
So the printer can also be reset by a signal on this port.

I also see that the switched +5V supply that also goes to their reset circuit, is controlled by Q1, that itself is controlled by the 'Power' rail. So locks-out the logic, if this is not present.

I've not yet found the paper feed switch on the schematic, that is also used for test-mode. But do need to get it out of reset first.

[SiriusHardware]

I did used to spray WD-40 into the ribbon cartridge, after taking the lid off

I had heard of the WD40 refresher trick but hesitated to mention it in case it was just one of those Urban legends which circulate quite widely, but don't actually have any merit. You may be the first person I know to have tried it and found it to be viable.

[ScottishColin]

This is definitively an EPSON 3110 inside - see attached phot.

Colin.

Originally Posted by ortek_service

I've now also managed to work-out which of the (Both confusingly labelled EPSON, and not sure what the other '3110' label refers to) diagrams applies. As the manual doesn't make it clear what the 2022 and 2023 differences are.
I've also not managed to work out how a 3022 / 3023 differs, other than they are targeted at specific PET model series. And that the PET 2001(N/B) doesn't apparently have print routines built in, and you must have a printer customised or use with either the 2001N or 2001B?
But hopefully any PET 30xx / 40xx model can be used with a 30xx printer.

The only Commodore printers I recall having much experience of was a (Seikosha? based) MPS-801 (Commodore cut-down IEEE-488) 'Serial' one on the C64, where after fitting a new ribbon, the head wasn't returning to start. But this just used a very long coil spring to do this, and a bit of WD-40 freed-up the slightly-sticking mechanism.


Both 2022/2023 manual schematics seem a bit over-complex, having RAM (and timers + I/O) split between two 6532 'RIOT' IC's. And there's a crucial typo that says the ROM is in a 6332 (So easily confused with a 6532 / an RRIOT, with ROM in it), when it is actually (luckily) in a 'standard' 2332 dedicated ROM IC.
Hopefully these are all OK - But at least there are ways of replacing these if the originals are not available
(Assuming there's a copy of the ROM out there on the 'net, if it unfortunately ever fails / to verify it is still OK)

It seems to me that nIRQ (which is also a feed into their reset circuit) is driven by a (OR) gate of '4B' (Is there a table anyway to translate these PCB positions to real part numbers? - As seems to be lacking on the schematic / 'Cross-Reference' parts list / B.O.M) which is driven by an 'IFC' line from the IEEE-488 port connector (Pin 9), that is Pulled-high with 3k3 and pulled low with 6k8 'termination' resistor networks.
So the printer can also be reset by a signal on this port.

I also see that the switched +5V supply that also goes to their reset circuit, is controlled by Q1, that itself is controlled by the 'Power' rail. So locks-out the logic, if this is not present.

I've not yet found the paper feed switch on the schematic, that is also used for test-mode. But do need to get it out of reset first.

[SiriusHardware]

There doesn't seem to be a 6B on this board - I'll annotate the drawing that is in that PDF in a while to try to properly locate everything.

That may just be a problem with the poor reproduction of the document - what I thought looked like 6B may instead be 4B, to verify that, check for continuity between 4B (6) and 7B (25). If you do have continuity, measure the resistance between 4B (6) and 0V.

[ortek_service]

Originally Posted by ScottishColin

This is definitively an EPSON 3110 inside - see attached phot.

Colin.

>>
>>

Well that's very confusing that on the Schematic they've referenced that (Actually turns-out to be the mechanism) number on, isn't actually the one being used with it in this case. And it might have been more logical if they'd put the Control board part no. in the title, instead, being as they both use the same 3110 mechanism.

But I guess they just reprinted the Epson one, where Epson did have different control boards for their different mechanisms. (Although, using the same main 'Commodore' IC's, and having the IEEE-488 interface, would rather indicate that this too was really a Commodore design, just made by Epson for them)

However, Commodore calling their own version of the control board 'Epson Printer Logic. is also a bit confusing, when in a manual for ones that all used the same Epson mechanism, but different control board makes / designs.
But again, I guess Commodore had different control boards for different mechanism manufacturers (if they were using any others at that point), so had labelled their schematic as being for an Epson make (But model of mech. would also have been helpful!)

I'm still wondering what physical differences there are between the 202x and 302x models, as the external pictures I found looked rather similar.

[ScottishColin]

Resistance between 4B pin 6 and 0V - 6.4kΩ.

Colin.

Originally Posted by SiriusHardware

That may just be a problem with the poor reproduction of the document - what I thought looked like 6B may instead be 4B, to verify that, check for continuity between 4B (6) and 7B (25). If you do have continuity, measure the resistance between 4B (6) and 0V.

[ScottishColin]

Actual documentation for this printer (3022) is very difficult to find - most Commodore equipment has been scanned/saved but the 3022 seems to be an exception.

The only document I can find that explicitly has the 3022 in its title is below (but is in German and has no schematics in it):

http://www.zimmers.net/anonftp/pub/c..._3022_3023.pdf

Colin.

Originally Posted by ortek_service

Well that's very confusing that on the Schematic they've referenced that (Actually turns-out to be the mechanism) number on, isn't actually the one being used with it in this case. And it might have been more logical if they'd put the Control board part no. in the title, instead, being as they both use the same 3110 mechanism.

But I guess they just reprinted the Epson one, where Epson did have different control boards for their different mechanisms. (Although, using the same main 'Commodore' IC's, and having the IEEE-488 interface, would rather indicate that this too was really a Commodore design, just made by Epson for them)

However, Commodore calling their own version of the control board 'Epson Printer Logic. is also a bit confusing, when in a manual for ones that all used the same Epson mechanism, but different control board makes / designs.
But again, I guess Commodore had different control boards for different mechanism manufacturers (if they were using any others at that point), so had labelled their schematic as being for an Epson make (But model of mech. would also have been helpful!)

I'm still wondering what physical differences there are between the 202x and 302x models, as the external pictures I found looked rather similar.

[TonyDuell]

As an aside, Epson made an optional IEEE-488 interface board for some of their printers (MX80,etc). But it used ASCII, not PETSCII. When I first looked at the Commodore service manual mentioned in this thread, I thought the Epson board schematic was just a reprint of an Epson centronics-interfaced printer, for reference. It isn't of course.

AFIAK the only difference between the 2022 and 3022 is the number printed on the case. Commodore wanted to make it seem applicable to the later series of PETs. They did the same sort of trick with their disk units too.

[ortek_service]

Originally Posted by SiriusHardware

I had heard of the WD40 refresher trick but hesitated to mention it in case it was just one of those Urban legends which circulate quite widely, but don't actually have any merit. You may be the first person I know to have tried it and found it to be viable.

Yes, I think I read it in a computer-magazine and I hadn't really got much to lose as compatible ones I bought were only around £2-£3 each. But had packed-up not too long afterwards, when I wanted to print something.
I did the WD-40 trick several times, and it can result in a bit messy prints to start with, as excess WD-40 goes onto paper (even after trying to eliminate excess from inside the cartridge)

I expect there are better solvents to use, to redistribute ink from unused upper / lower areas of the ribbon. It would also probably be better to use actual ink, but excess of that would no doubt make a lot more mess so can't just poor that across the ribbon. It might be possibly to make a re-inking device, with an ink-soaked foam roller in contact with the ribbon, as it is fed over this.

Genuine Epson etc ribbons probably lasted longer, but I doubt any will be too good after nearly 40years!

[ScottishColin]

I asked this question on a Facebook group a while back and got the following reply:

"I believe all the 30xx model numbers are the European versions on the 20xx line.

When the PETs with full size keyboards were released, they kept the 2001 name and 20xx series in the US but changed to 3000 series in Europe.

The 3016 is the same as the 2001-16N and the 3040 floppy drive is the same as the 2040."

Colin.

Originally Posted by TonyDuell

As an aside, Epson made an optional IEEE-488 interface board for some of their printers (MX80,etc). But it used ASCII, not PETSCII. When I first looked at the Commodore service manual mentioned in this thread, I thought the Epson board schematic was just a reprint of an Epson centronics-interfaced printer, for reference. It isn't of course.

AFIAK the only difference between the 2022 and 3022 is the number printed on the case. Commodore wanted to make it seem applicable to the later series of PETs. They did the same sort of trick with their disk units too.

[SiriusHardware]

Resistance between 4B pin 6 and 0V - 6.4kΩ.

With the machine on again, what state / what voltage do you see on 7B (25)?

And what voltage do you have on 4B (5)?

[ScottishColin]

7B pin 25 - low.

4B pin 5 - high at 4.27V

Colin.

Originally Posted by SiriusHardware

With the machine on again, what state / what voltage do you see on 7B (25)?

And what voltage do you have on 4B (5)?

[SiriusHardware]

7B pin 25 - low.
4B pin 5 - high at 4.27V

OK, power, off, please check for continuity between 4B pin 5, 7B pin 15 and the 'IFC' pin of the IEE488 connector. This is to make sure we are definitely looking at the right gate.

Question for Tony, most likely?

As far as I can make out the IFC input on the IEEE488 interface is biased by a 3K3/6K8 voltage divider to about 2/3 of 5V which in the eyes of gate 4B 4/5/6 will be a logic '1' and will result in a low output state on IC 4B (6) and therefore applied to the input of the reset timer circuit.

Does the printer need to be connected to an actual IEEE488 host in order to see a 'low' state on the IFC input?

[ScottishColin]

According to this I believe the IFC pin to be pin 9 - is that correct?

Colin.

Originally Posted by SiriusHardware

OK, power, off, please check for continuity between 4B pin 5, 7B pin 15 and the 'IFC' pin of the IEE488 connector. This is to make sure we are definitely looking at the right gate.

Question for Tony, most likely?

As far as I can make out the IFC input on the IEEE488 interface is biased by a 3K3/6K8 voltage divider to about 2/3 of 5V which in the eyes of gate 4B 4/5/6 will be a logic '1' and will result in a low output state on IC 4B (6) and therefore applied to the input of the reset timer circuit.

Does the printer need to be connected to an actual IEEE488 host in order to see a 'low' state on the IFC input?

[SiriusHardware]

And Colin, I'm assuming that all checks and tests since this thread started have been with the printer stand-alone and not connected to either of the PETs. Do you have a printer cable?

Yes, the IFC pin of the IEE488 connector looks to be pin 9.

[ScottishColin]

Yes - all tests have been carried out with no cable connected.

I have a few and have already tried connecting to the PET with no joy but cann again.

Colin.

Originally Posted by SiriusHardware

And Colin, I'm assuming that all checks and tests since this thread started have been with the printer stand-alone and not connected to either of the PETs. Do you have a printer cable?

Yes, the IFC pin of the IEE488 connector looks to be pin 9.

[ScottishColin]

Apologies - fr the record I meant to add this link:

https://en.wikipedia.org/wiki/IEEE-488

All continuity checks out OK between 4B pin 5, 7B pin 15 and Pin 9 of the IEEE port.

Colin.

[SiriusHardware]

Can you (...always with power off on both units) connect the printer to one of the PETs, turn the PET and printer on and check the voltage on 4B (5) again?

Just heading off for lunch.