Triumph Adler DRH80

[powerlot]

Hi all

Bundled with my recent Alphatronic P2 haul (see here) was a serial dot matrix printer from Adler model number DRH 80 GAD 201. I took it apart, replaced the line filter, cleaned and lubed all relevant moving parts (I also made a copy of the EPROM).

Unfortunately, I can't find any information about this printer in the web. It should be a serial port printer, but whenever I set it on line it prints one character non-stop (which deafening and annoying).

If anyone has any idea about the DIP switch configuration and how to interface with it I would really appreciate it!

Thanks

 

[Chuck(G)]

It might be useful to monitor pin 14 on the 8251 (RxRDY). If that were stuck low, it would appear that a character was always ready.

 

[powerlot]

Thanks for the pointer and a likely scenario, as it looks a bit random to me when it starts doing this. Unfortunately the 8251 is deep in the back below the paper feeder and it's really difficult to reach a probe in for measuring. At this point I also don't know if the DIP switches are correct or have been messed with in the past. I cleaned them to make sure they don't make the printer act strange.

There is a RED and YELLOW led next to the on-line switch. The RED led always comes on when powered, the YELLOW one is random. Sometimes it clears, sometimes not. What I know is that some part of the communications is not working, as according to the manual, when typing in a .PP statement into the machine OS the system will hang if CTS isn't sent (which at the moment is never).



I'm one gender changer short of being able to attach the printer to a modern computer, where I'll probably be able to test it further.
Settings according to the manual:
1 start bit, 8 data bits, 2 stop bits, no parity

 

[Chuck(G)]

Unless you're sending at 110, one stop should be sufficient. (Not really a bit; just the spacing between one character and the next, so you can have, for example, 1.5 stop bits).

 

[RetroAND]

There were more hardware references in the Italian service manual - it was actually much more complete than the Deutsch one. I remember having seen other devices attached at the end of the document, I will search and examine it.

EDIT:
I see there is a 8212 and a 8156 from the MC-80 family. If you have problems with them, I can help you source them.

 

[powerlot]

Where can I find the Italian documentation? It would be nice to have that too, especially if it has more details
Thanks!

 

[powerlot]

I received my gender changer... unfortunately I can't get the printer to do anything over the serial port with what I guess could be correct settings (serial connections are before my time...)



@RetroAND any luck finding the Italian service manual? Without any documentation for this printer im poking in the dark

With the printer attached to something (or just randomly...?) it at least stopped printing gargabe at its own will.

 

[powerlot]

I hooked up my computer to the Alphatronic P2's printer port via null modem cable. In its default settings, logging the monitor output to the printer port works with the following settings (1 stop bit also works as mentioned by Chuck):



Using the same settings to send data to the printer doesn't work. When I send a text file, it produces garbage text lines similar to the ones reported in post #1, but with some other characters sprinkled in between.

I am now certain that either the DIP switches are not correctly set or the serial communication circuit is borked.

 

[powerlot]

Updates:

I managed to get actual strings of characters out of this printer. It required cleaning the paper feed microswitch and it looks like TA really didn't want you to operate this with the lid open. There is an obvious switch to the right of the paper transport which stops the printer but it must have been something additional (maybe interference or light).

Anyway I'm happy that there are no faults, just unknowns to figure out now.

This is a valid configuration:

Null-modem connection
LF as line break
the DIP switches set as follows:

	1	2	3	4	5	6	7	8
		X				X	X	X
OPEN	X		X	X	X

EDIT:
4800 baud, set like the picture in post #1
the DIP switches set as follows:

	1	2	3	4	5	6	7	8
		X				X	X
OPEN	X		X	X	X			X

it was right after all, having the lid off just made it do weird things (such as still printing garbage with the wrong settings)

 

[powerlot]

Courtesy of the VzEkC forums, the manual: https://archive.org/details/ta_drh80_bedienungsanleitung

I'll order a new ribbon and matching cable and call this one done