DIY Bluetooth Retrofit CM5908

[dfraid]

Here is my schematic that builds on both of your designs.

[bbowman]

Hey bbowman, how did you connect to the volume board?
Did you strip the wire? I have the harness out with a header pin showing the correct position (I believe) but I can't really tell how you combined them? or did you just abandon the 8 pin female harness and just plug the TG into the male end of the volume board.?

So I actually soldered the wire directly o the top of the volume board where the female plug header is. If you look at the PDF I created with a bunch of the small pics with annotations, you will se it in the bottom left corner. You actually don't need the signal from the orange wire. I removed that wire from the plug and just taped it off with some electrical tape. What you do want is the signal from the volume board, which captures the momentary switch input from the volume knob. I hope that makes sense. If you look back at that PDF with all the pics I think it should be clear.

[dfraid]

So I actually soldered the wire directly o the top of the volume board where the female plug header is. If you look at the PDF I created with a bunch of the small pics with annotations, you will se it in the bottom left corner. You actually don't need the signal from the orange wire. I removed that wire from the plug and just taped it off with some electrical tape. What you do want is the signal from the volume board, which captures the momentary switch input from the volume knob. I hope that makes sense. If you look back at that PDF with all the pics I think it should be clear.

You're talking about soldering right here? (I think I see it on the PDF now that you mentioned it)
I tried it with a T-tap (you can see the orange wire it exposed slightly) but I am having a couple of issues.

1. No audio, but that might be the head unit itself - I will know tomorrow when I test it with a cassette.

2. I have no way of toggling the radio vs Bluetooth. I turn on the head unit and the Bluetooth connects right away.

[bbowman]

Yes that is exactly where I soldered a wire, but you also need to disconnect the original orange wire from the volume board. My guess is that whatever exists down that orange wire is switching the latch and turning on your BT module. You can either remove the orange wire from the female end of the plug, or just snip it. I removed mine with a small pointy tool so that I could revert it to original if I want. You just have to press down on the little tab and pull it out. Once you remove that wire, you should be able to test the latching circuit. On radio power-on, you should have no voltage on the V_out of the latch (and hence your BT module should be off). Once you push in the volume knob, that should pull the Trigger input on the latch to ground, causing V_out to go to +12v, which turns on the BT module.

And regarding audio out - I think your board has a head phone output doesn't it? So you could just pop in some headphones to test and then if that works and your still having issues it must be amplifier related.

[dfraid]

Yes, that is exactly where I soldered a wire, but you also need to disconnect the original orange wire from the volume board. My guess is that whatever exists down that orange wire is switching the latch and turning on your BT module. You can either remove the orange wire from the female end of the plug, or just snip it. I removed mine with a small pointy tool so that I could revert it to the original if I want. You just have to press down on the little tab and pull it out. Once you remove that wire, you should be able to test the latching circuit. On radio power-on, you should have no voltage on the V_out of the latch (and hence your BT module should be off). Once you push in the volume knob, that should pull the Trigger input on the latch to ground, causing V_out to go to +12v, which turns on the BT module.

And regarding audio out - I think your board has a headphone output, doesn't it? So you could just pop in some headphones to test and then if that works and your still having issues it must be amplifier related.

Okay, bbowman that kind of worked!
- Soldered the pin on top and disconnected the orange wire from the plug
- Power push button works
- The Drok headphone jack test worked
- Cassette worked / still works - I reversed everything to check
- The radio works

I just can’t get audio from the drok to the head unit. I double-checked my wiring still nothing…

tyeler18 any suggestions?

[bbowman]

Okay, bbowman that kind of worked!
- Soldered the pin on top and disconnected the orange wire from the plug
- Power push button works
- The Drok headphone jack test worked
- Cassette worked / still works - I reversed everything to check
- The radio works

I just can’t get audio from the drok to the head unit. I double-checked my wiring still nothing…

tyeler18 any suggestions?

I just looked over your previous posts, and at some pictures of the DROK module from Amazon. I noticed a marking on the board from the Amazon add that looks like "LGR" pointing to the 3-pin connectors on the board. I assume this is "Left-Ground-Right" corresponding to the pins.. I noticed in your diagram you linked above that you had the ground wire as the far left pin. Is it possible you just have one of your wires switched? No ground could be causing your issue.

[dfraid]

I just looked over your previous posts, and at some pictures of the DROK module from Amazon. I noticed a marking on the board from the Amazon add that looks like "LGR" pointing to the 3-pin connectors on the board. I assume this is "Left-Ground-Right" corresponding to the pins.. I noticed in your diagram you linked above that you had the ground wire as the far left pin. Is it possible you just have one of your wires switched? No ground could be causing your issue.

Yes you’re right, the diagram is incorrect - I thought that was the issue as well.
but I double checked the wiring and used a fresh cable that came with the Drok and header pins to just plug and play without any luck.

[captain confused]

I got mine working with the Pioneer last august and it sounds great! Really throws people off when I change songs with my phone and take calls in the car. Cool mod for old radios with defunct tape decks.

[chicaneS54]

Will this work with the CM5907?

[bbowman]

Will this work with the CM5907?

I don't have experience with the 5907, but I know they are very similar to the 5908... If the internals look similar to the pics posted here (same number of pins, same wire colors) I would say chances are pretty good that it would work. However if any of the wiring looks different, then you would need to reverse engineer the new pin locations.

The general theory of operation should certainly apply. The only question is if the various pins and wires are the same across the two radios.