Timex Sinclair 2040 Printing problem

Discussions about Sinclair ZX80 and ZX81 Hardware
BrettRogersUK
Posts: 13
Joined: Sat Aug 06, 2022 12:19 am

Timex Sinclair 2040 Printing problem

Post by BrettRogersUK »

Hi All,

I have acquired a Timex Sinclair 2040 printer along with a couple of Alphacom 32 printers.

I have been testing them today and found that the 2 x Alphacom printers print without problem when doing the self test. They print the 8's and 1's without problem.

However the TS2040 prints the self test but it doesn't print 8's and 1's, instead it prints different characters. (See Pic).

I was wondering if anyone knew what this problem may be and how I can fix it. Is it a problem with a chip on the board? Hoping it's not the ROM.

Your thoughts are welcome.

Regards

Brett
User avatar
mrtinb
Posts: 1906
Joined: Fri Nov 06, 2015 5:44 pm
Location: Denmark
Contact:

Re: Timex Sinclair 2040 Printing problem

Post by mrtinb »

There is not picture.
Martin
https://zx.rtin.be
ZX81, Lambda 8300, Commodore 64, Mac G4 Cube
BrettRogersUK
Posts: 13
Joined: Sat Aug 06, 2022 12:19 am

Re: Timex Sinclair 2040 Printing problem

Post by BrettRogersUK »

Hi,

Apologies, it would appear that it didn't accept my picture that I attached.

Here it is, see attached.

Thanks,

Brett
Attachments
20220813_211236.jpg
BrettRogersUK
Posts: 13
Joined: Sat Aug 06, 2022 12:19 am

Re: Timex Sinclair 2040 Printing problem

Post by BrettRogersUK »

mrtinb wrote: Sat Aug 13, 2022 10:10 pm There is not picture.
Hi,

I've had this printer plugged into my spectrum and printed "Hello World" as a test 10 times.

While it has received the print command and printed the word it is barely recognisable. Its as though it is missing some of the dots.

I note from the schematic that there are 4 IC's that feed the print head. Could it be possible that one or more of these has failed and need replacing? I hope it isn't as they are difficult to get hold of in the UK.

Regards,

Brett
TS2040 print out from Spectrum 48k
TS2040 print out from Spectrum 48k
Last edited by BrettRogersUK on Sun Aug 14, 2022 12:16 am, edited 1 time in total.
User avatar
1024MAK
Posts: 5101
Joined: Mon Sep 26, 2011 10:56 am
Location: Looking forward to summer in Somerset, UK...

Re: Timex Sinclair 2040 Printing problem

Post by 1024MAK »

Yes, it could either be one of the chips, or a poor connection affecting the data.

Mark
ZX81 Variations
ZX81 Chip Pin-outs
ZX81 Video Transistor Buffer Amp

:!: Standby alert :!:
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb :!:
Looking forward to summer later in the year.
BrettRogersUK
Posts: 13
Joined: Sat Aug 06, 2022 12:19 am

Re: Timex Sinclair 2040 Printing problem

Post by BrettRogersUK »

1024MAK wrote: Sat Aug 13, 2022 11:57 pm Yes, it could either be one of the chips, or a poor connection affecting the data.

Mark
Hi,

I hope it isnt one of the IC's that run the print head. They are difficult to get hold of now and I don't know of an alternative.

They are all UCN4401A chips

Regards,

Brett
User avatar
1024MAK
Posts: 5101
Joined: Mon Sep 26, 2011 10:56 am
Location: Looking forward to summer in Somerset, UK...

Re: Timex Sinclair 2040 Printing problem

Post by 1024MAK »

It may also be a mechanical problem.

Mark
ZX81 Variations
ZX81 Chip Pin-outs
ZX81 Video Transistor Buffer Amp

:!: Standby alert :!:
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb :!:
Looking forward to summer later in the year.
BrettRogersUK
Posts: 13
Joined: Sat Aug 06, 2022 12:19 am

Re: Timex Sinclair 2040 Printing problem

Post by BrettRogersUK »

1024MAK wrote: Sun Aug 14, 2022 12:33 am It may also be a mechanical problem.

Mark
Hi,

What would be the first thing to look at to try and solve this puzzle??

Regards,

Brett
User avatar
XavSnap
Posts: 1940
Joined: Sat May 10, 2008 4:23 pm
Location: 'Zx81 France' Fb group.

Re: Timex Sinclair 2040 Printing problem

Post by XavSnap »

Hi Brett,

It's not a printer problem.

The Spectrum don't target the IR register to the UDG memory. (48kb offset)

The ROM isn't set to a 48k memory ram set up and picking up UDG data in a wrong location.

Spectrum only sends dots, not the real character.
Try a COPY, but try to move(copy) the UDG array to the 16k location, to retrieve the good UDG offset.

(Try the printers on a ZX81 !)
Xavier ...on the Facebook groupe : "Zx81 France"(fr)
BrettRogersUK
Posts: 13
Joined: Sat Aug 06, 2022 12:19 am

Re: Timex Sinclair 2040 Printing problem

Post by BrettRogersUK »

XavSnap wrote: Sun Aug 14, 2022 12:36 am Hi Brett,

It's not a printer problem.

The Spectrum don't target the IR register to the UDG memory. (48kb offset)

The ROM isn't set to a 48k memory ram set up and picking up UDG data in a wrong location.

Spectrum only sends dots, not the real character.
Try a COPY, but try to move(copy) the UDG array to the 16k location, to retrieve the good UDG offset.

(Try the printers on a ZX81 !)
Hi,

Thanks for the info, however how does it account for the self test printing wrong when not connected to a computer?

If I had a ZX81 I would gladly test it on there! 🤣🤣🤣

Thanks again,

Brett
Post Reply