Sinclair ZX80 / ZX81 / Z88 Forums

Hi all,

I'm looking for some advice on how to repair my Alphacom 32 / TS 2040 printer.

The attached picture shows the self-test output followed by what should have been:
TEST 1
TEST 2
TEST 3
TEST 4
(repeated a few times)

I cleaned the contacts of the edge connector. This helped me go from the TS1000 crashing after most LPRINT attempts, to being able to run programs with loops containing LPRINT. I am also now able to use the computer with both the printer connector and 16k RAM expansion connected simultaneously.
I also cleaned the PCB end of the ribbon connectors inside the printer.

Would you have any ideas as to what could be wrong?
Do I just need to scrub the contacts harder, or could something more serious be at play?

I once read somewhere that Memotech RAM modules needed a certain DIP switch setting to work with the Alphacom but cannot swear to the truthfulness of it,Sinclair's module should be OK though. The Alphacoms are generally very robust and as the self test is producing actualprint then I would say the actual printing mechanics are OK and the fault lies somewhere in the connection chain.

Does the printer perform OK without the RAM module attached?

Thanks for responding.

The output you see is without the RAM pack installed (mine being a TS1016). I'll try doing a deeper clean of the connections later.

The interface between the computer and the printer is unusual. The signals used by the computer were designed for Sinclair's ZX Printer. Loss of any one of the output signals from the computer will result in the printer not working correctly.

From your photo, is it doing line feeds from the computer okay?

If yes, that points to the data line that controls the pixel printing.

As suggested by a member earlier, the self test working okay is a good sign that most of the printer is okay.

Hence I agree that the most likely problem is a poor connection between the computer and the printer electronics. That would include the connection cable.

Mark