SEGA Saturn SOPHIA - CUSTOM Build of rare MDR50 "VCD" cable

Discussion in 'Sega Saturn Programming and Development' started by Gerry_MAN, Sep 17, 2017.

  1. Gerry_MAN

    Gerry_MAN Spirited Member

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    Hi Folks,

    A Friend of mine here, owns a Sega Saturn SOPHIA Programming BOX, along with the JVC PC-IF3 Emulator interfacing card. He is missing the very rare type of MDR50 cable assembly, that is used on this system for the "VCD" interface. As shown Below:

    [​IMG]

    I offered to build this cable for him to help him out.

    Now just to inform you all, my background is mainly in Digital-Electronics, and I am currently working in the Filed of "Test-Development" for a manufacturing company. I have been working in the filed of digital-electronics and also Robotics for the past 5 or 6 years. So with that said, putting a cable like this together is just a routine process.

    I recently assembled a similar type of connector for a RARE N64 Development cartridge called the
    IS-VIEWER64 and I managed to get the unit up and running.
    You can check out the details on this endeavor at the link below:
    https://assemblergames.com/threads/is-viewer-64-custom-scsi-cable-working.66597/

    So Now,
    here is a photo I found of the actual "VCD" interface cable.
    The unique thing about this cable is that it uses Receptacle (FEMALE) connectors as part of the Cable assembly. This is not the norm.....It is more common for Cable assemblies to use MALE (PLUG) connectors.

    [​IMG]


    A similar cable assembly that uses the "Receptacle" type of MDR connectors is shown below....
    This is just for your visual reference of the connector style:

    [​IMG]


    As you can see here in the photo below, the Male "PLUG" connectors are actually installed on the SOPHIA Programming BOX and are also used on the JVC PC-IF3 Emulator Card for the "VCD" interface.

    [​IMG]

    [​IMG]


    Notice the specific difference here with the male PLUG connectors compared to the Standard "3M MDR50".
    And that is... the extruded Alignment TAB's on the top and bottom.

    [​IMG]

    This difference in their design, requires that the Receptacle connectors used on the cable assembly, must have a slight decreased in the "Width measurement" from top to bottom. At least compared to standard MDR50 connectors. For it to mate perfectly.... this is a requirement.


    So, now I have already done a significant amount of research on these rare MDR type of connectors. Some discussion surrounding this topic, have previously been discussed here on AssemblerGames....Link below:

    https://assemblergames.com/threads/saturn-scsi-need-cable.12141/


    So after reading all of this and also checking with some of my own contacts, I have actually found a source for these very Rare types of MDR connectors through one of my contacts. Similar connectors are used with Logic Analyzer interfacing hardware. Unfortunately, the contact I have made is a bit reluctant to give out too many details on their source... and also any of the specs. I'm suspecting these were a custom build for the JVC emulator cards. Regardless, I did receive a few images which are shown below:

    These are basically a Custom variant of the standard "3M" MDR50 series of connectors and Receptacles and are made in Japan.
    Also Just to point out: "PLUGS" = MALE connectors "RECEPTACLES" = FEMALE connectors.


    As shown in the image below you can see the Alignment TAB's are present....this is the same as those used on the SEGA Saturn SOPHIA hardware. So at least this confirms that I have ordered the right connectors.

    [​IMG]


    So NOW!!!
    This is where I need some help from you all here in the DEV community.

    I am hoping that someone here who already owns this Special "VCD" cable for the SOPHIA programming Box, would be willing to run some CONTINUITY tests on the cable for me?

    This I need to verify, to make sure that the Cable wiring from one end to the other, is in fact a "1....to....1" configuration and does not use some strange wiring configuration.

    Usually these types of digital communication cables Like SCSI......use a configuration called:
    "Straight Pass Through"

    This simply means they use the following wiring sequence from one connector to the other.
    Pin#1---- to---- Pin#1
    Pin#2---- to---- Pin#2
    Pin#3---- to---- Pin#3
    ^
    |
    Pin#48---- to---- Pin#48
    Pin#49---- to---- Pin#49
    Pin#50---- to---- Pin#50



    However, JVC and SEGA may have decided to create a custom wiring sequence between the two ends of the cable connectors as extra security or possibly for some other special reason.

    So it could be different and be like this:
    Pin#1---- to---- Pin#50
    Pin#2---- to---- Pin#49
    Pin#3---- to---- Pin#48
    ^
    |
    Pin#48---- to---- Pin#3
    Pin#49---- to---- Pin#2
    Pin#50---- to---- Pin#1



    So this is why I need someone who owns the cable to check the CONTINUITY between all the 50 Pins. Just to confirm that it is in fact a "Straight Pass Through" cable and uses a Pin#1---- to---- Pin#1 configuration for all 50 pins in the cable assembly.


    So for those of you that might not be familiar with the "Continuity check".....
    this is a Test you perform using a "MULTI-METER" that is set to the "CONTINUITY" mode.


    By connecting the probes from PIN#1 on one side of the connector
    to PIN#1 on the opposite......if they are in fact wired together it will create a TONE sound.
    This is essentially the same test used for checking Fuses. A Graphic Image of this process is shown below:


    [​IMG]

    [​IMG]

    So this is where I am at Folks..... I need your help!

    If we can confirm this cables wiring sequence, then I can move forward and build this cable and test it on the SOPHIA System. Hoepfully it is a Pin#1---- to---- Pin#1........"Straight Pass Though" cable. :p


    Anyhow,
    I hope to here back from someone who can help me.
    Cheers Folks!

    Kind Regards,
    Gerry O'Brien
    http://www.digital-circuitry.com

     
    Last edited: Sep 22, 2017
  2. jollyroger

    jollyroger Robust Member

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    Hi Gerry,
    I seem to recognize the cable as being similar or identical to the one connecting the Cross Products CartDev Saturn Virtual CD port to the Mirage CD emulator.
    If that is the case, I have that cable, and if noone else does it, when I have some time I can do the continuity tests on it.
    Jollyroger
     
  3. Gerry_MAN

    Gerry_MAN Spirited Member

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    @jollyroger,

    That is Great!! :D

    As long as we can confirm that these cables are the same...and that they are in fact interchangeable.
    I would need to see some kind of documentation stating this.... just to be sure.

    Another quick way we can confirm this....
    Can you check your cable for a Serial # or Cable Assembly # ?
    Most custom made cables like this will have a Label that has transparent Heat-Shrink tubing covering it.

    I would like to compare these model # with those shown on a cable from someone that actually has an official "VCD" cable assembly for the SOPHIA Programming Box.

    I wonder if the manuals state the Cable Assembly numbers? I'll have to double check that.
    Hopefully someone can come forward and provide a Photo of the cable for us?


    Thanks so much for your help. :D
    Cheers!
    -Gerry
     
  4. jollyroger

    jollyroger Robust Member

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    Hi Gerry, I have the cable in my hands, and it looks literally identical to the one in the first picture (the one with the three cables).

    It comes with the same ferrite cores, and the very same label "Manufactured by Devlin Electronics LTD Basingstoke Hants Tel No. 01256 467367" :)

    If the cable in that picture is from the Sophia box, then I am pretty sure the cables are identical, given that they serve essentially the same purpose...

    Jolly
     
  5. Gerry_MAN

    Gerry_MAN Spirited Member

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    @jollyroger WOW!! Fantastic!!

    That is Great News!
    Well....whenever you can fit the time in to perform that continuity test....That would be EPIC!!

    Thanks so much for your help @jollyroger......it is really very much appreciated. :D

    Cheers!
    -Gerry
     
  6. jollyroger

    jollyroger Robust Member

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    I will do the continuity test, but please keep reaching out to people with the Sophia box, so that we can try to completely ensure that it is indeed the same cable, even though evidence clearly points towards it...
    Jolly
     
  7. Gerry_MAN

    Gerry_MAN Spirited Member

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    @jollyroger Perfect!

    You Bet!!
    That's the reason for this post!! :cool:

    The plan is to toss this Link at... as many people as possible ....possible owners of a SOPHIA system.....or just other interested Saturn developers. Then maybe we will get lucky, and find the info we need.

    Do you think you could still take some Hi-Res close up photos of the Label on your Cable?
    And also some close up shots of the MDR Female receptacle connectors on this cable assembly?

    Just so we have shots of an actual SEGA cable of this rare MDR type, and that is used with the SEGA Dev gear.
    Thanks again so much for all your help.

    Cheers!
    -Gerry
     
  8. jollyroger

    jollyroger Robust Member

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    Sure, I will take the pictures as soon as I have a little time... I am swamped at work right now.
    Jolly
     
  9. Jackhead

    Jackhead Moderator Staff Member

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    The cable Jollyroger has is the cable you are looking for. I made the first picture and yes thats your cables Jollyroger :).
    Will be great when you can share us the pinout. They really rare cables..
    Great Kit and interface card btw.
     
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  10. Gerry_MAN

    Gerry_MAN Spirited Member

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    Hi @Jackhead,

    Do you still have this cable with you?

    If you do...and it is the one you used with the SOPHIA Programming BOX "VCD" port...
    Could you also take some Hi-Res close up Photos of the Cable Label....... and also the Cable assembly end connectors?

    Again...just so we have it here on file for the record.
    That would be amazing if you could.

    Let me know.
    Cheers!
    -Gerry
     
  11. jollyroger

    jollyroger Robust Member

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  12. Gerry_MAN

    Gerry_MAN Spirited Member

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    Woaahh!! Sweet!

    You can clearly see the cable Label too....it is in Perfect Focus!! :D

    @jollyroger
    This is Awesome!!

    One more thing though if you are able and willing..??

    On the Cable itself....there is also some printed Gray Text....this indicates the type of Cable used.
    This is also very important for us to know, in case there are individually "shielded twisted pairs" of cable inside.
    This internal pairing is referred to as "STP".

    Also...if there is any way you can take a picture of the connector End...so that the connector socket is in perfect focus?
    I hate to be picky...sorry....but the one you sent is a bit blurry.

    -Gerry
     
    Last edited by a moderator: Sep 21, 2017
  13. jollyroger

    jollyroger Robust Member

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    The writing on the cable reads: "AWM 2789 VW-1 FURUKAWA-T"

    I will try to take more closeup pictures of the connector, but I don't have a camera that can focus that close.

    Jolly
     
  14. Gerry_MAN

    Gerry_MAN Spirited Member

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    Sweet! That's awesome.
    Thanks @jollyroger.

    In Regards to Photos:
    Well whatever you can manage with the camera you have is fine.....
    Just Take like 20 photos with the cable connector up close at different distances. Eventually you'll get one with the connector in Focus.

    If you look at the photo you sent....
    your Hand is in Perfect focus there...lol. :p
    So just play around with it a bit and I'm sure you can land a shot of it in Focus. :))

    Thanks again for doing all this leg work.....it is really appreciated.
    It will be pretty Epic if I can get this cable to work.

    Cheers!
    -Gerry
     
    Last edited: Sep 20, 2017
  15. retro

    retro Moderator Staff Member

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    If you read some of my previous posts on the Saturn systems, or the manuals, you'd know that the interface is the Saturn VCD interface. It was used on all hardware and is for connecting a virtual CD device, either the JVC card or Mirage.

    The connector was custom made for Sega and the manufacturer won't even discuss it. Basically... this was made for Sega, you're not Sega, this discussion is over.

    It is different from all other similar connectors in a number of ways. It took me a LOT of faffing about, snapping things off etc. to get anything to mate with a Sega connector. Not to mention buying lots of connectors that weren't right! lol. You'll see my comments in the thread you referenced on the 3M MDR, which wasn't right... firstly, you'd be using a PCB socket not a cable assembly, which is far from ideal... and then you had to take the shielding off. There are some that were somewhat better, although still needed modification. I forget the brand now. Did you order connectors intended for cables, or are they PCB mounting sockets?

    Ultimately, it would probably be easier and cheaper to change the socket and use a standard cable.... but I guess not everyone would be willing to do that.
     
  16. Gerry_MAN

    Gerry_MAN Spirited Member

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    Hi @retro,

    Thanks for jumping in here to help out.....

    I did realized the cable was for the VCD interface... and that it was for connecting a Virtual CD device.
    I did at least read that far in....LOL :D After all, this was what my Friend asked me to look into building for him.

    However, confirming that this cable was the same cable that @jollyroger was in possession of, and also if it was interchangeable between the MIRAGE....this was where I was Stumped.

    I did start to go through the manuals, but I've been so caught up with many other thing on the agenda, that I still haven't had the time to go through them all.... so Thank you for confirming that they are in fact interchangeable. That is great to know. :) Your knowledge of this equipment is appreciated.



    I'm not surprised.....manufactures are always so tight lipped....but I guess they have to be
    as they are bound under the policies of a signed contract. :(

    As @jollyroger mentioned in his previous post...the Label on the cable indicates that the cable assembly was Manufactured by Devlin Electronics LTD. and they would be bound by their contract with SEGA to not discuss the design requirements with anyone.

    Also as you mentioned the 3M MDR50 connectors are the wrong connector and will not work. Period!!
    The connectors on this SEGA cable assemblies are a different connector entirely. It is either a Standard connector from one of many manufacturers......or it is a custom design that was built from scratch by Devlin Electronics.... ($$$$$$ very expensive) which is quite possible as Devlin does offer Custom design services right on their website:

    https://www.devlin.co.uk/custom-design/

    So if this is the case then we are dead in the water .....exactly as you said, and we will have no choice but to perform a MOD and switch out the connectors with a more common one.



    LOL...I hear you there my friend. ;)
    The Trial and Error process can be really grueling........and Frustrating!! *#*&@*&!

    However, I believe that I may have found the connector they ended up using in this cable assembly!!
    (.....maybe!! I emphasize.... "MAYBE!!" .... LOL )


    I'm coming from a manufacturing background perspective here......so hear me out:
    Usually for Low production builds.....in this case...The SEGA Saturn Development equipment....
    These are low production products for SEGA. They don't plan on selling Millions of them compared to their consoles. A simple way for them to save big $$ on production, is to use "Off The Shelf" components instead of going custom.

    So as you yourself, were buying and testing various connectors....it is still very possible that Devlin Electronics and SEGA decided to use a specific Brand of connector and we simply need to identify which one they used. As you well know, there are more than a handful to choose from. With that said, I think I may have finally found it!!





    If it is in fact a Custom connector then you're probably Bang On here!
    We may have no choice but to do a custom MOD.

    However, I'm hoping we won't have to....and that I have actually found the connector they used.
    We'll have to wait and see if the connectors I got are a match.

    I'll try and Hunt down the Datasheets for the connectors I have ordered....and also the specs for the cable that was used. I'll follow up and post them here for everyone to check out.

    I'll keep you all posted.
    Cheers! Folks,
    -Gerry

    @jollyroger,

    If you get a chance at some point to retake the Photo of the cable connector,
    I would really appreciate it.

    Thanks for all your efforts.

    Cheers!
    -Gerry

    Hi Jackhead,
    Do you still have your Saturn Dev setup with this cable?

    -Gerry
     
    Last edited by a moderator: Sep 26, 2017
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  17. HI_Ricky

    HI_Ricky Peppy Member

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    i still find any way to build this cable for my Mirage CD :(
     
  18. Gerry_MAN

    Gerry_MAN Spirited Member

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    Hi Ricky,

    I have not forgotten about this project....
    I am just in the process of verifying some potential connectors. I have shipped these "TEST" connectors to an owner of a SEGA SOPHIA development system, as well as the JVC interface card to confirm or deny a positive match.

    Once he receives these connectors in the mail, he will test them on the SEGA SOPHIA development equipment to verify if they mate correctly with no resistance..... or if not at all. :eek:

    If the connectors are a Match..... then I can proceed to build the SOPHIA interface cable.

    However, keep in mind this is a 50/50 chance that it is in fact a match.
    We will just have to wait and see.

    My Friend should be receiving the Test connectors in about 2 weeks.
    So we'll know the outcome hopefully before Christmas.


    I'll keep you posted.
    Cheers! Everyone.
    -Gerry
     

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