MSX Palcom laserdisc help

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By Shertz

Supporter (5)

Shertz's picture

31-12-2020, 19:29

Hello MSX friends. Somewhat new to this group and to the MSX computer.

I seem to be having trouble connecting my laserdisc player to my Pioneer PX-V7 Palcom MSX computer. I've connected the Palcom to a laserdisc player that is similar to the LD-1100 that has an mono input jack. The LD player starts up fine when I type CALL LD. It also is able to do searches. The Palcom can detect what LD game is playing. But after that, the Palcom dosent do anything else. The Palcom plays through the attract sequence once and searches back to the beginning and the process starts over. After a few times of this I eventually get a an error message.

Please watch the YouTube video.

Yes, I am using high quality cables. Yes, my player is fully working. No, I don't 'think' the laserdisc has laser rot. No, I don't have a working LD-700 or equivalent player to test. And I have tested other palcom laserdiscs and same thing happens.

Any help is greatly appreciated! Thank you!!

https://youtu.be/ISb1hz3W13o

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By st1mpy

Paladin (825)

st1mpy's picture

31-12-2020, 22:58

I'm not an expert or have a setup, but do you just have 1 cable connected between the msx and ld? I guess that just controls the ld remotely from msx. I think a cable to load the game data from ld to msx is missing?

By djh1697

Paragon (1597)

djh1697's picture

31-12-2020, 23:34

The Pioneer LD1100 is mentioned in the service manual, the LD700, and LD7000 are mentioned in the MSX FAQ, along with the connection diagram, not sure if that is helpful? I have used the superimpose on the PX7, but never had the chance to use the Laserdisc interface. There is just the one cable, if you look at the pinout connections it has got both I/O connections. If the cable is not working correctly you might only be seeing the introduction screen?

https://www.faq.msxnet.org/connector.html#LD-700IO

By st1mpy

Paladin (825)

st1mpy's picture

31-12-2020, 23:59

These ld games start by loading the game from ld to msx, like a tape game. So it says Found, so the msx found the game data on the ld. Then it fails after that. I don't know how long the load is meant to be, so not sure if it is waiting for the ld to load to msx or it loaded and msx fails.

By NYYRIKKI

Enlighted (5873)

NYYRIKKI's picture

01-01-2021, 00:07

Check that you have not mixed up Left and Right channel RCA-cables and that the cables coming from LD-player are connected to sound input and not sound output.

By djh1697

Paragon (1597)

djh1697's picture

01-01-2021, 00:27

NYYRIKKI wrote:

Check that you have not mixed up Left and Right channel RCA-cables and that the cables coming from LD-player are connected to sound input and not sound output.

Surely that would not cause the game to crash and restart though?

By NYYRIKKI

Enlighted (5873)

NYYRIKKI's picture

01-01-2021, 00:41

djh1697 wrote:
NYYRIKKI wrote:

Check that you have not mixed up Left and Right channel RCA-cables and that the cables coming from LD-player are connected to sound input and not sound output.

Surely that would not cause the game to crash and restart though?

I think it just tries few times and then gives error... The description of the problem definitely points towards wrong connected audio cables... The remote controller cable seems to work fine as the player starts to play.

By NYYRIKKI

Enlighted (5873)

NYYRIKKI's picture

01-01-2021, 01:46

Ah, sorry, my bad... I didn't check the video... As there is "Found: STELLAR" then the cables can't be totally wrong... This seems more like audio quality problem...

Edit: removed my stupid ideas

I think it might be in the signaling after all... Maybe the player does not return ACK on some case? ...or something like that (These are just wild guesses here)

Louthrax wrote:

Here's the pinout of the LD-700 Laserdisc player:

      7  1
           4
    a   b   c
           i
      g  h 

Pin functions from the LD-700 Laserdisc player side are:

     1   I  INT/ /EXT
     4   O  /EXT ACK
     7   I  EXT CONTROL
     a   -  GND (this is also the shielding)
     b   O  +11V (do not use as a powersource)    
     c   O  RF
     g   -  NC
     h   -  NC
     i   O  VIDEO (75 Ohm)

More details on the pin functions:

    PIN DIR NAME       FUNCTION
     1   I  INT/ /EXT  Signal when Laserdisc stops playing.
                       Used by the MSX to stop superimposing before it loses v-sync.
     4   O  /EXT ACK   Confirm command and completion.
                       When the MSX sends PLAY to the Laserdisc, ACK is held low
                       while the disc spins up. It goes back up once the disk is
                       playing.
     7   I  EXT        Commands sent from MSX using the NEC IR protocol.

I think here is the best "documentation" how it all works, if you can just decipher it:
https://github.com/openMSX/openMSX/blob/master/src/laserdisc...

By Shertz

Supporter (5)

Shertz's picture

01-01-2021, 02:04

Thank you all for responding. I'm starting to think there's something faulty with my MSX computer. The player I'm trying to use is an LD 1100 and that uses a 3.5 mm mono Jack. Not the LD 700. I can't find any information and how to properly connect the MSX to a LD 1100 LaserDisc player. The actual LD 1100 does not have an input jack. I have read elsewhere that you're supposed to connect and IR-LED and acts like a remote control.. I have ordered and IR LED on eBay so I'll try to see if that helps but I don't see that it would. As I continue to get error messages.

By Shertz

Supporter (5)

Shertz's picture

01-01-2021, 02:12

Does anyone have a scan of the px-v7 manual. I know there is a px-7 on here. But I just want to make sure that the V7 is the same.

By mars2000you

Enlighted (5984)

mars2000you's picture

01-01-2021, 08:11

It's the same manuals for both Japanese machines:

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