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ZX81 Memotech Interface Problems

Posted: Sun Oct 12, 2025 2:59 pm
by t0nyt
Hi, I'm trying to get retro-printer working with a ZX81 & Memotech Centronics Interface without any luck so far

Have checked continuity of my ribbon cable and am happy that's ok

As I have no way of knowing for sure that the memotech is working I was wondering if anyone knew if there was any way to find out on the retro-printer side what communications it is (or isn't) having with the zx81/memotech, without resorting to logic probes, please?

Many thanks
Tony

Re: ZX81 Memotech Interface Problems

Posted: Sun Oct 12, 2025 4:03 pm
by RWAP
Tony,

Are you capturing any raw data at all? The best way is to monitor the /tmp directory for raw files whilst printing.

If they are corrupt, then you will not a PDF - but you should see something in there.

You may need to adjust the handshaking, signal_time and bit_depth settings to get it to work with the ZX81.

Re: ZX81 Memotech Interface Problems

Posted: Mon Oct 13, 2025 1:37 pm
by t0nyt
RWAP wrote: Sun Oct 12, 2025 4:03 pm Tony,

Are you capturing any raw data at all? The best way is to monitor the /tmp directory for raw files whilst printing.

If they are corrupt, then you will not a PDF - but you should see something in there.

You may need to adjust the handshaking, signal_time and bit_depth settings to get it to work with the ZX81.
Not getting anything (other than a couple of random characters when I unplugged/replugged the connectors)

I did find that if I printed without retro-printer attached it didn’t error or hang the zx81 (not sure if that’s a good or bad thing though)

Will look at the settings you mention

Many thanks