VOGONS


First post, by Boohyaka

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Hoy,

Got myself a MPU-401 breakout box from a retired musician. It wasn't used in years but was perfectly stored and looks great. He didn't have anything else though - no interface card, no cable.
Purchased a regular DB25 cable (from what I've read from Great Hierophant's blog, it should be fine?) and a MIF-IPC-B clone card (pre-assembled).

I left the interface card config by default, so 330h IRQ2/9. I booted and...immediately noticed computer sounds coming out of the small piezo speaker inside the MPU-401, definitely at a level that cannot be normal. Tried to run stuff and it is not properly detected (DOSMID says "MPU not detected", and running games, no midi message is received by the MT-32). Trying to send a command with MPUTHRU.COM freezes the computer.

Thing is, I usually have a PCMIDI MQ clone in that computer, running at default 330h IRQ2/9 as well, and running perfectly fine, so I doubt it is an interface card settings problem or conflict?

Any thoughts?
Cheers

Reply 1 of 6, by keropi

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did you check the LPT cable pinout to match the one on the Lo-Tech wiki? https://www.lo-tech.co.uk/wiki/Lo-tech_MIF-IPC-B
it's the "Roland MIF-IPC Cable Pinout" pdf link at the end

🎵Link to buy a PCMIDI mpu
🎧Orpheus soundcard project
💻WTB Amstrad PC7486SLC-33 system

Reply 3 of 6, by Madowax

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Boohyaka wrote on 2020-09-09, 14:35:

you must be right as always...assumed all cables would be the same but the pinout seems weird in my cable... i'll figure out a proper cable and try again! thanks!

JFYI I used a simple DB25 extension cord and a gender changer at one end and it works perfectly fine. Extension cord must be straight pin to pin with all pins connected.

Manhattan, 6FT DB25 Male to Female Data Cable, 301565

StarTech.com DB25 Slimline Gender Changer M/M - Serial / parallel gender changer - DB-25 (M) to DB-25 (M) - GC25SM

Last edited by Madowax on 2020-09-09, 15:28. Edited 1 time in total.

Reply 4 of 6, by Boohyaka

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Yep that's my issue...I assumed my cable was straight pin to pin, but it isn't when I tested continuity...I opened it up and it only has 11 cables, and even those aren't pin to pin but all over the place. no idea what shit cable i got, it was advertised on ebay as a DB25 male-to-male cable and I just assumed it would be fine..it wasn't. Lesson learned.

Reply 5 of 6, by Madowax

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Boohyaka wrote on 2020-09-09, 15:27:

Yep that's my issue...I assumed my cable was straight pin to pin, but it isn't when I tested continuity...I opened it up and it only has 11 cables, and even those aren't pin to pin but all over the place. no idea what shit cable i got, it was advertised on ebay as a DB25 male-to-male cable and I just assumed it would be fine..it wasn't. Lesson learned.

I used this two:

Manhattan, 6FT DB25 Male to Female Data Cable, 301565

StarTech.com DB25 Slimline Gender Changer M/M - Serial / parallel gender changer - DB-25 (M) to DB-25 (M) - GC25SM