Centronics Cable and Mixed up Signals

[decuser]

Hi,

I bought a v3 retro printer awhile back and have just now gotten around to using it. After struggling to figure out why:

10 PRMN\ "Lmllo, orll!"
20 OO\O 10

Was being read from the port when:

10 PRINT "Hello, world!"
20 GOTO 10

Was sent. I got out a multimeter and looked at the pins on the male and female side of the centronics M/F adapter thing that came with my retro printer. It appears that Pins 4 and 5 on the male side are both wired to pin 4 on the female side and they are both wired to pin 5, as well. Is this per design? Because it seems faulty to me. These pins are listed as DATA BIT 3 and DATA BIT 4 here:

https://pinoutguide.com/ParallelPorts/i ... nout.shtml

Which would seem to cause the issues of bits being wrong as above (any time bit 3 and/or bit 3 are high, both bits 3 and 4 will go high and only when both are 0 then bits 3 and 4 will stay low.

Anyhow, is it a problem or am I confused about how it works? If it's a problem, what's my fix?

Will

[decuser]

OK. So... the fix was to take the adapter apart and inspect it for solder bleed. Sure enough, there was cruft bridging pins 4 & 5. I got it off with my exacto knife, put it all back together again and voila:

10 RMM ABCLMNOLMNOLMNOPQRS\]^_\]^
20 RMM abclmnolmnolmnopqrs|}~|}~
30 RMM 0123<=>?<=0 -_=/_]?>/",<.>
<0 RMM /?!@#,-^..,-

10 REM ABCDEFGHIJKLMNOPQRSTUVWXYZ
20 REM abcdefghijklmnopqrstuvwxyz
30 REM 01234567890 -_=+[];:'",<.>
40 REM /?!@#$%^&*()

Y'all gotta be more careful putting these things together. I'm a retro enthusiast, not a hardware guy. This adapter thingamig shoulda just worked. But, thanks for putting the retro printer doohickey out there. It works great now! Off to see if I can get it going to my actual printer (cups works fine, so I gather once I get my config settings back where they belong, it'll do its thing).

[RWAP]

Ah yes, my apologies - one or two of the metal cable adaptors have proved to have a minor issue where the solder manages to bridge 2 pins. Unfortunately, they are home made - we do try to test them all before they are shipped

[decuser]

No worries (ha! just occurred to me that this is an Australian comment, isn't it? - good ol' Crocodile Dundee), anyway all's well that ends well