88-94 Factory Stereo Info

Discussion in 'Audio + Electronics' started by AK49BWL, Apr 9, 2020.

  1. df2x4

    df2x4 Domestics only.

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    If you go to mediafire.com you can upload the file there and post a download link here for free. No account necessary. Just right click on the file name once it's done uploading and then click "Copy Link."

    EDIT - Looks like they only retain the files for 14 days unless you register an account though. On the bright side, it's still free to register.

    DOUBLE EDIT - DropBox and Google Drive are some other similar options.
     
    Last edited: May 22, 2020
  2. Sportbike23

    Sportbike23 Newbie

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    Eveready and df2x4 like this.
  3. AK49BWL

    AK49BWL GMT400 Forever!

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    I use Google Drive for the larger files myself. That link worked great, you mind if I rehost it on my Drive for future access? This looks very useful!

    Now I'm gonna have to pull apart one of my older CDMs.. This is for the two-board units. What interests me more is the list of vehicles these were used in.
     
  4. Sportbike23

    Sportbike23 Newbie

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    Yeah, go for it, hope it helps!
     
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  5. df2x4

    df2x4 Domestics only.

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  6. CorvairGeek

    CorvairGeek Newbie

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    Don't know if a lot of people realize it, but GM also used CDMs though a lot of car lines with the higher end radios. Some were attached to the radio, while some were remote, like the trucks. Some really remote (Cadillacs) and had them in the trunk.

    Here is a 91 Riviera radio that had an external CD player. It has a 2 PCB CDM with a build date of 1990.

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    I think this amp does sound better than the non EQ version of this stereo.
     
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  7. AK49BWL

    AK49BWL GMT400 Forever!

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    I'm definitely going to have to check more vehicles when I go back to the salvage yard now lol.

    The Cadillac radios are an interesting bit of work, particularly the BOSE versions.. The CDM is the same physical size pretty much, but has no internal amps: The BOSE amps are attached to the speaker boxes! Four individual amps on the Caddy and Corvette BOSE systems. I really want to get my hands on one of these lol. I also don't know if any of those came with 5-band EQ. The non-BOSE CDMs seem to be the same as the truck CDMs tho.



    @CorvairGeek I see THAT one has the 5-EQ :D external CD player you say??? Hmm! I'm guessing the controls are on the deck itself?

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    Interesting! Given that, I wonder if it's compatible with the truck heads or CDMs. The display definitely isn't, obviously, considering there's no CD indicators. Would be kinda cool to see what it does lol. Also whether the EQ system on the car CDM works with the trucks digital EQ display. Thanks, now I am going to go find some more radios to hoard!




    Oh, also just gonna throw this down here for the heck of it... How to adjust the tape player's playback speed. I'm not gonna get into the precision aspect of it but the quick version is this.

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    That hole in the top of the motor between the two ribbon cables is the adjustment hole. A small, preferably plastic, flat-blade screwdriver can be used to turn the motor's internal potentiometer to adjust the motor speed. I say preferably plastic because a metal one can ground out on the frame of the motor.. Which won't hurt anything, but will max out the motor speed when it happens lol.

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    Go clockwise to make it faster, counter for slower.
     
    Last edited: May 22, 2020
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  8. CorvairGeek

    CorvairGeek Newbie

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    I believe that the CD player did look like that. I didn't test it or take it. It was fed into pins 11-16 of the CDM. I convert everything for an aux input, so I haven't messed with cassettes or CD sections.
    The pin out is on the cover of this CDM below. Not all of them are marked, for what ever reason.
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    The Bose and non-Bose are physically the same and the same pin outs, just missing the amplifier section, as you noticed. I've got both variants of this radio;

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    The pinout of the Bose CDM, from a '93 Park Avenue;
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    This was from a '93 or '94 LeSabre / Park Avenue, IIRC;
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    The CDM separated for the 'head' for testing and aux input setup;
    [​IMG]
     
    Last edited: May 23, 2020
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  9. AK49BWL

    AK49BWL GMT400 Forever!

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    I have that same pinout on a few of mine as well... Was always very curious how to activate the pin 11-16 Aux input but never really looked into it. Didn't even know any other vehicles used it, but now I see, clearly some do!
     
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  10. CorvairGeek

    CorvairGeek Newbie

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    IIRC, going high or low on 'DATA' does all the switching for inputs, not a specific, signal or pulse. These even kick up the volume one increment which switching from the radio, which matches the volume level better.

    [​IMG]
     

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