Playing MP3s using your original Previa radio.

[Jonny]

My 91 just had the radio and tape player, no CD unit. I finally got tired of pirating tapes to play and have rigged it up to accept the tunes on my iphone. This is a $10 job.

On the back of the unit is a 13 pin din plug...

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Here is a link to a post I found which details what these pins do. I also used this post as a basis for my mod.
https://www.miata.net/garage/externa...interface.html

You will need...

13 pin male din plug...

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Female 3.5mm jack outlet (shown after soldering)....

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... and a length of shielded cable.

I used 2 wire cable and a simple jack outlet, rather than the four wire and closed jack the Miata guy used in the above link. More on whether that was the right thing to do later.

Now it's basically some careful soldering. See the link for the pins to solder to. My method just uses #2 (left input), #4 (right input) and #5 (cable shield/signal ground).

On the photo below the ground goes to the center row left pin, the right input to the bottom row right pin, the left input to the bottom row 2nd from left....

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Anyway, the pin diagram in the link is correct.

For soldering the female jack, the larger tab is the ground/shield, the tab connecting to the mid depth contact is the right channel (you can easily see this one down in the hole) and the bottom of the hole is the left channel.

So when I installed the radio I found that the iphone input plays on top of whatever is playing on the radio or the cassette. Since the Miata guy had said that the Miata unit came with a factory plug connecting pins 1/2 and 3/4 when there was no CD player, and since the previa does not need a plug to function without a CD player, I assumed I didn't need to do the extra stuff. Looks like I haven't quite grasped the concept somewhere.
However, it still works great - I got a sacrificial cassette, removed the tape so that it can be played continuously with no tape sound, plug in the iphone and voila. Good enough.

Depending on where you mount the jack you may have to do minor surgery on the dash. I had to file away a few hidden mms of plastic...

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It's good here, right next to the tray...

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Hopefully this helps some other tightwad with similar needs and if anyone else has done this a better way please let us know.