OverLOAD

I purchased a Mazda Tape add in module for a single purpose only: To play MP3's from an external source. Initially I though that if my Idea of installing a 1/8" headphone jack, directly wired into the module didn't work, I would still be able to use a regular tape adapter.

Heres what I bought, and here's the results.

- Mazda RX-8 (same as Mazda 6) Tape player add-in module & Faceplate
- 20 foot Headphone extension cable (6-ft is plenty)

You'll need a soldering Iron, a scredriver and a bit of patience and bravery.

1. Unpack the goods: My New Mazda Tape module:

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2. Pop the cover off the unit.. (unscrew the two screws in the back, on the bottom, the big side with the connector) then lift up the cover plate:

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3. Then locate the little Printed Circuit Board (PCB) that is located below:

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4. Next, prepare your headphone extension cable. I used a cable with a female end, since I wanted it to look less noticeable. Then locate the following specific points on the circuit board.. notice the little labels on the PCB silkscreen R-CH & L-CH.. they were very handy in figuring exactly where I should wire this together

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5. Then run your extension cable up the back of the tape module through this hole.. Once it's through, tie a tight knot in it to prevent it from coming back out.

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6. Then solder on the 3 wires as shown below. For reference, I used a radio shack extension cable. If you happen to want to use the same type of cable, I got a 20' extension cable for about $7.99. The yellow wire goes to the tip of a male connector (Left Channel), the red goes to the middle connector (Right Channel), and the back wire goes to the base connector (Signal return/ground).

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6b. Here's a closeup of the solder connections..

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7. Then close up the unit, and prepare for installation.

Follow the instructions in the install booklet for installation. However, before you put everything back together, run your wire for the AUX in, behind the head unit console, and down under where the ashtray is, then run it forward, and towards the cup-holders (or some other location you would prefer

I cut a little hole in the edge of the clip that's next to the E-brake, so that the wire would have a better fit without being crimped.

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Viola! You are done! (If you put everything back together). I left out a few steps, but you should be able to figure everything out from the tape module. The most confusing thing I ran into was the small retaining bolt that goes into the side of the radio. It's actually right on the side of the radio (on the left side for North American vehicles), and way, way in the console. I only managed to do it with a screw-driver with a socket attachment. I think it was a 10mm bolt..

OverLOAD

Look at this! My MP3 player is all snug!

Happy hacking!


Some final comments.. It's probably possible to do a similar type hack to the CD units, but I wasn't brave enough to hack into that.. I needed something cheaper

And the Audio Quality? Absolutely Terrific. My fourth tape adapter, a high quality unit, which was the pick of the litter of several such units was pretty good, but this AUX line in bypass is as good as it gets. Is it reliable? What's the signal level like? Yes, and good. It's not as loud as it could be, but that's a good thing. It's probably possible to blow up parts of the tape module with too much volume.



OverLOAD

züm- züm

Ah, this HOWTO will come in very handy for me when OmniFi comes out. Has anyone seen this system yet? From what I understand, since it is wireless, you'll be able to drag MP3's into your RX8 right from your desktop.

Info links here:
http://www.omnifimedia.com
http://www.techtv.com/news/ces2003/s...413922,00.html

Kev

So functionally, you just select "TAPE/MD" and play your MP3 unit?

Have you still got a fully functional tape player as a result?

This is really good!

I think I'd probably expose two RCA plugs in the centre consule near the power socket.

Thanks for all of your effort in posting you works.

Kev.

B-Nez

The reduced volume may be due to halving with the silent tape deck. Maybe cutting the tape signal and wiring in a toggle switch between external and tape? Cool stuff though. Are you experienced at this sort of stuff, or did you just sleep at a Holiday Inn Express last night? I ask because it takes cajones to trial and error a brand new (uncheap) radio. Hats off to you either way.

Gamera

Nice work!

Couple of questions: Do you need to have a dummy tape in (and presumably with the motors spinning) for the input to be audible? The cassette player still works normally, right? The audio levels of the cassette player still the same as before the mod (if by chance you listened to it before the mod)?

For about $160, this sounds like a cool solution for an AUX port, at least until/if Blitz or PIE comes out with an adaptor. I think those have generally run between $75-150, so the cost of OverLOAD's method isn't too bad. Running the cable through the cap in the cup compartment was a great idea, btw.

OverLOAD

Yup, I meant to mention that last night..

It only works with a dummy tape, so bust out that old tape you made of yourself when you were 8 years old, and pull the tape spools out. Insert the Tape, press the Tape/MD button, and you hear the Aux source. When you eject the tape, it mutes the input.

And by reduced volume, I mean just a wee little bit. I have the rockbox firmware on my Archos, and to get a volume level equal to the radio stations takes about 93% of maximum.. I'd just rather run it a little lower, and not take the chance.

It works really well. I kind of surprised myself by how easily it all seemed to come together. I was willing to take it all apart, since I figured the worst thing I'd blow up was the tape module.. And I wanted an AUX in Really bad!. In terms of my Experience with this sort of stuff, I'm pretty much a rank amatuer at Electrical design, however I'm resourceful enough to be able to find the datasheets for all the IC's that were on the Op Amp Eq PCB in the tape deck. That helped a bit.. I've taken apart a bunch of stuff before, but this is really my only motivation so far to actually do a useful mod to some gear that I had. This head unit was desperately in need of some AUX in..

Have fun, and like I said, this can probably also be done with the stock CD head unit, but you'd probably also need to burn a 'Dummy CD' of one track of blank audio to get that to work..

Net result is that this mod works very well, and I'm more than satisfied with the results.. And Yes, the tape player works 100% normally and will still play regular tapes. The sound levels didn't seem to change intensity at all... just remember to disable the AUX-in source when you do that so you don't have two simultaneous sources (and funny sound)..

However, standard disclaimer: I take no responsibility for any damage that you may do, while trying this mod on your own. I have mentioned everything that I feel is important to completing this mod successfully, but please don't blame me if you mess something up.

Otherwise, happy modding!

OverLOAD


Edit: p.s.

Just another note. I modified my previous tape adapter so that I removed the tape sender unit, and the headphone cable. This allows me to use this as the dummy tape, since a regular tape will keep cycling, and a tape that you've ripped the actual tape out of, will read "TAPE ERROR" on the LCD status screen... Other than that, it sounds great. If possible, get shielded extension cable. And on another note, someone elsewhere mentioned that there would be electronic interference in the tape module, corresponding to engine RPM's. I have not experienced this. I've even only heard of this in very old AM radios..

martinl78

The next best thing here would be to use an ohm meter/continutity tester to find out what pins on the output of the cassette deck actually carry the audio. And, what pin gives a signal to indicate that a tape is in the unit. If we could find this out, many folks could hook up what they need without having to buy a cassette unit to do it....and without having to make a dummy tape.

Gee, it would be so much simpler if Mazda would make a unit that would go in place of the cassette that would supply inputs (they could even put limits on them to protect the main unit).

Excellent work to even get this effort working even this well!

Attack

That's a great idea... something that you could put in the well for the cassette deck that has the inputs, maybe a face plate that had some depth so you could put in an ipod, hard disk mp3 player, etc.

It shouldn't be too hard to figure out where the signals are coming from in the cassette deck's conversation with the head unit, but the hard part would be how to replicate them.

I'd definitely be willing to pay 50+ bucks for something to plug into the bottom of the unit to give me an aux jack without the need for a cassette deck...

OverLOAD

These are both good suggestions, about a new module, and tracing the pins. And it's exactly what I tried.

Unfortunately, I was unable to determine exactly which pins on the connector carry audio. I used my favorite 20 function Fluke knockoff multimeter, and I was able to determine that about 7 of the pins on the connector are for ground.

If you are looking at the back of the unit, here's my guess of what's what:

Top of tape module:
Loads from (front) end (front = /|\ way)

Conenctor pinout:

1 . 3 . 5 . 7 . 9 . 11 . 13 . 15
. 2 . 4 . 6 . 8 . 10 . 12 . 14

1 = ground
2 = signal left?
3 = n.c ??
4 = signal right?
5 to 9 = ???
10 & 11 = +Vdc
12 & 13 = ground to battery
14 = ??
15 = ground

From what I tested, this is my best guess so far. This is only from memory as well.. I couldn't verify that this was correct, since I didn't run the unit outside of the car.

I would speculate as well that pins 5 to 9 are a databus connection. It's either a proprietary FMS Audio connection, or it's a CAN bus connection. There is a bug IC on the connector board that seems to handle all this good stuff.

In order to make a module that would function as an AUX in, and integrate seamlessly, would require the bus based capabilities of the FMS data bus, to tell the head unit what type of module it was, and what text to display on the LCD status.. (even just to say AUX would be a challenge, since you need to know the correct message code, and the formatting for the text).

To get this kind of setup working would be wonderful though, since you probably could fit most hard drive based MP3 players in the space the tape module uses, and you could get a little better sound quality, maybe even an SPDIF input connection. But to nail it, would take a lot of R&D to reverse engineer the bus traffic to make the head unit capable of switching into AUX mode from the tape button, and built a module capable of sending the signals. Basically, if FMS Audio gave us the schematics and even some help with the software for the chips, it would still be a big job.. I'm satisfied with this, unless someone else develops an add-in module, or an AUX kit.

Cheers!

OverLOAD

Attack

You're the man, Overload

I think you're spot on with the difficulty level of coming up with something from scratch to solve the problem. So maybe a good alternative is thinking about how to do surgery on the existing tape deck module to get what we need.

Do you think it would be possible to:

* Remove the "guts" of the cassette deck and leave the electronics in tact

* Fool the electronics into thinking there's a cassette in place all the time. If I recall right, most cassette decks have a switch that's depressed when the cassette is inserted -- if this is how the FMS deck detects the presence of the tape, just soldering the two ends of the switch wires together should permanently close the switch.

* Display is something I don't even want to begin to think about Though it would be nice to be able to eliminate the tape error message... maybe tinkering a little with the tape head would let us figure out a way to make it think there's a signal coming from a cassette.

* Line the interior shell of the cassette mechanism with that "no slip" stuff you can get to stick your cell phone, etc to your dash.

* Carve out a larger gap in the face plate to allow access to leave your audio device in that space.

I'm thinking out loud, so if anyone has better ideas, I'm all for it.

Thanks a lot overload for forking out the money and doing this investigation -- we all really appreciate it.

martinl78

Were those tracings done while the tape deck was operating?

I'm not sure if you'd have to issue a message. I was thinking it might have some line that would assert a signal while a tape was inserted.

I've never seen one of the cassette decks so I'm kinda in the dark. But if I had one and could hook it up, my thoughts were to try to interrogate each of the lines coming out of the deck while it was working to determine potentially what each one was.

--Heck, would even be cool to have have an interface panel or other compartment in place of the ash tray compartment that could be used for a MP3 player where you could still have the cassette or MD option. (I know...I'm dreaming a bit.)

Speed Racer

OverLOAD,
I took the easy way out and had an FM modulator installed so that I could hook up my iPod. It sounds OK but there is now doubt that it would sound significantly better with it hooked up directly. So I'll probably hack my radio too. Thanks for taking the time to figure out a way to get a line input into the radio and documenting it for the rest of us! :D

I think that you were referring to my comment in another thread about the electrical noise that can happen with cassette adapters. My last car was a '01 Celica GT-S and when the cassette adapter was inserted I would get a high pitched whine coming through the speakers that would increase with the RPMs. I spoke with one of our electrical engineers at work and he mentioned that the cable coming out of the cassette adapter is probably acting like an antenna and it is picking up EMI from the engine because it is not properly grounded. Regardless you shouldn't have that problem with your setup because your cable is grounded. Good job!

OverLOAD

All the traces were done with the unit OFF... That's the best I could come up with. Since I couldn't be sure about the left & right channels, I decided not to tap in there. Also, that is post OP Amp, so it would probably require more power from the mp3 player to drive it as high, if it's even audible. The impedance matching here is the most critical part to not blow up the head unit.. too much volume, and your head unit could fry. Also, it's possible that they just used the audio bus as the signal carrier for the sound source, which means that a digitally encoded signal has to be sent via the connector, which is too much work.

Now, As to ripping apart the tape guts... The Phantom tape has to have one of those car adapter kit thingies that both spins the tape spools, and the tape slack, fixed speed feeder, next to the tape pickup head. If you use a tape that doesn't have one of these, the tape deck never un-mutes the sound from the pickup head, and will display 'tape error'. This would likely be the result of a speed sensor on the RPMs of the tape spools... Too fast spinning means that the fixed rate spooler isn't working, and that the tape is either getting chewed up, or has snapped. This is likely controlled by the main IC on the connector PCB. Simulating this will be very difficult, however removing the tape innards would not be so hard. The spooler motors, and eject equipment could be removed without much trouble, but finding a way to get the speed sensor from the spooler motor thinking that its spinning slow enough (or even at all?) would be a problem. But this would give you all kinds of room to work with. Everything to the left side of the tape pickup head. That's big enough for even my Archos jukebox to fit inside...

As for putting no-slip inside it, I think that it could cause heat built up problems.. Did you look at how many vent holed are in the housing? It looks like they are there to keep the unit at a reasonable temperature, so blowing those vents with a pretty plastic case, or vinyl cover could cause ment-down... But If you did manage to rig it up, and get the tape deck to pass an audio signal, I'd probably remove the tape mechanisms pickup head, to try improbving the signal quality as well.. It would probably be significant. Those little heads seem to pick up EMI & RFI at very low levels that are audible at higher volumes with no actual sound source.. But the factory cover is plenty big enought to carve out, and has substantially less reinforcing then the tape module. You also wouldn't need the eject or Dolby NR buttons, so the factory module might be the best way to go. Except for the gaping hole in the dash, it wouldn't look too bad. It would even save willing hackers of the tape module from needing to but the special faceplate. They could use the factory one..


So, to sum it up, yes it's possible to fake out the tape deck and pull out the innards, you just would have to be careful how far you went, and that you could resolve all the little detection metords for the tape deck. It would probably survive a no-slip pad on the bottom (heat builtup?), but getting the faceplate to look good would be the next challenge. Perhaps your really good with acrylic moldings?

Anyway, I had a lot of fun with this, and am happy to just have something that work..

OverLOAD

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Speed Racer:

Yeah, That was the comment I was referring to... I've never heard a tape deck make that noise before, but it could be a grounding/EMI or RFI problem.. It could be the CD player picking up the EMI from the alternator. Those alternators are *very* loud in the EM spectrum.. lots of hum. good filtering (power stiffening capacitors) and grounding can help..



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ectomort

I imagine some of the wires (5-9 perhaps?) handle control signals for fast-forward, rewind, skip ahead, and skip-reverse.

OverLOAD

ectomort:

Nope, I think that from the tape module, to the 'mother' module, there's only a digital bus (speculation). The eject & Dolby reduction buttons are on the front connector, and likely only do stuff within the tape module.

OverLOAD