DIY Bluetooth Retrofit CM5908

[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.

[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.

[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]

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]

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]

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]

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]

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

[dfraid]

Awesome yeah that latch board looks perfect.

And yeah if you can source the proper ribbon cable connector that would make the install super clean. I did the quick-n-dirty approach of just soldering a wire to the pad of the ribbon cable. No need to shave the pad or anything it takes solder fine just the way it is. The only catch is you need to use a VERY thin gauge wire. If you use a thick wire, it will put too much force on the solder pad when your moving all the parts around and it will start pulling the trace away from the cable. After I finished I also wrapped the connector in kapton tape to further help prevent strain on the solder joint, and also insulate the other pins on the cable.

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.?

[bbowman]

Thank you bbowman !
I actually got one from icstation- just arrived.

https://www.icstation.com/mobile/sin...02-p-9309.html
It just has a single voltage and single toggle pin as opposed to the one you used with two of each / 6 pins. So hopefully that simplifies the wiring further.

I am just trying to get my hands on FPC connector to plug into the cassette ribbon cable. I can’t really tell how you got access to the ground pin but it looks like you shaved that particular pin(#14) on your diagram and soldered to it?

The ribbon cable looks like its 18 pins and has a 1.25mm pitch.

tyeler18 what pins did you use to connect the power and ground on the Drok? The holes look pretty large.

I will document my process and upload it as a hybrid solution between both of your suggestions

Awesome yeah that latch board looks perfect.

And yeah if you can source the proper ribbon cable connector that would make the install super clean. I did the quick-n-dirty approach of just soldering a wire to the pad of the ribbon cable. No need to shave the pad or anything it takes solder fine just the way it is. The only catch is you need to use a VERY thin gauge wire. If you use a thick wire, it will put too much force on the solder pad when your moving all the parts around and it will start pulling the trace away from the cable. After I finished I also wrapped the connector in kapton tape to further help prevent strain on the solder joint, and also insulate the other pins on the cable.

[dfraid]

Hey so the latching circuit I think works great. feels very OEM to just push the volume knob and have it switch over to bluetooth. Unfortunately the latch I used looks like it's hard to get at least in North America. Any latching circuit should work. There seem to be plenty available from China if you don't mind waiting a long time. This is essentially the same one I used: https://www.ebay.com/itm/30397982088...EAAOSwNWBcjMSO. If you search something like "bistable latch" or "bistable flip-flop" on eBay/Amazon you will get a bunch of boards that all more-or-less do the same thing. If you have any questions i'm happy to help

Thank you bbowman !
I actually got one from icstation- just arrived.

https://www.icstation.com/mobile/sin...02-p-9309.html
It just has a single voltage and single toggle pin as opposed to the one you used with two of each / 6 pins. So hopefully that simplifies the wiring further.

I am just trying to get my hands on FPC connector to plug into the cassette ribbon cable. I can’t really tell how you got access to the ground pin but it looks like you shaved that particular pin(#14) on your diagram and soldered to it?

The ribbon cable looks like its 18 pins and has a 1.25mm pitch.

tyeler18 what pins did you use to connect the power and ground on the Drok? The holes look pretty large.

I will document my process and upload it as a hybrid solution between both of your suggestions

[bbowman]

Thanks for the clarification tyeler18. Do you think it would be possible to use the latching circuit proposed by bbowman with the Drok? Do you have a photo of your external switch - Just curious what it looks like and how it's mounted. Where you drawing power from?

Hey so the latching circuit I think works great. feels very OEM to just push the volume knob and have it switch over to bluetooth. Unfortunately the latch I used looks like it's hard to get at least in North America. Any latching circuit should work. There seem to be plenty available from China if you don't mind waiting a long time. This is essentially the same one I used: https://www.ebay.com/itm/30397982088...EAAOSwNWBcjMSO. If you search something like "bistable latch" or "bistable flip-flop" on eBay/Amazon you will get a bunch of boards that all more-or-less do the same thing. If you have any questions i'm happy to help

[tyeler18]

Thanks for the clarification tyeler18. Do you think it would be possible to use the latching circuit proposed by bbowman with the Drok? Do you have a photo of your external switch - Just curious what it looks like and how it's mounted. Where you drawing power from?

Yes the latching relay should work fine. I don't have a picture but its a toggle switch mounted on a dummy button above the radio. It draws power from the radio ignition wire.

[dfraid]

Radio functions normally-
I'm not using the latching circuit, I have an external switch that powers the drok on. With it powered on it enables bluetooth and you connect to it like a normal bluetooth device. It auto connects on power up anytime after that. I don't have a resource for removing the cassette drive but once you get the radio apart it's obvious and easy to do.

Thanks for the clarification tyeler18. Do you think it would be possible to use the latching circuit proposed by bbowman with the Drok? Do you have a photo of your external switch - Just curious what it looks like and how it's mounted. Where you drawing power from?

[tyeler18]

Hey tyeler18 and bbowman.

I am about to undertake this project. I have my working deck and I just received the Drok bluetooth module. The switching circuit is on the way still. I have a few clarification questions,

1. Does the radio function work normally?
2. The bi-stable latching circuit, that just allows you to control the volume with the knob and or power up the Drok module?
3. How do you connect to the Drok System once its been installed? Do you just press the Mode button and it recognizes it as a cassette ?
4. Do either of guys have a resource on removing the cassette from the radio itself?

thank you.

Daniel

Radio functions normally-
I'm not using the latching circuit, I have an external switch that powers the drok on. With it powered on it enables bluetooth and you connect to it like a normal bluetooth device. It auto connects on power up anytime after that. I don't have a resource for removing the cassette drive but once you get the radio apart it's obvious and easy to do.