Makita Radio Bluetooth Upgrade BMR102/DMR102

With the Makita BMR102/DMR102 not having support Bluetooth, I figured it was a waste of money to just buy a new Bluetooth enabled one just for the sake of having Bluetooth. So I figured I'd simply add a Bluetooth module to it...

Supplies

This was the Bluetooth module I went with, the same one can be bought from Core Electronics or pretty much anywhere if you just search for "Bluetooth module board".

The Makita radio I went with was the BMR102, however I needed to replace the amplifier too which I salvaged from DMR102 which has a very similar circuit board so I would dare say if your Makita radio has the same looking circuit boards I'd imagine this same instructable would apply. (just test using the methods listed below)

You will also need a soldering iron (and obviously solder) and some wire.

(if you need to replace the amplifier you may need a solder wick, and if you wish to replace the thermal compound you may as well get some thermal paste)

Step 1: Disasemble the Radio

First start by taking apart the radio, there are 4 allen key screws on the front and 2 philips screws inside the battery compartment.

Step 2: Replacing Amplifier (Optional)

(If you aren't having any problems with the amplifier you can skip this step)

One problem I had with this radio was a popping sound at above medium volume which I put down to a bad amplifier considering how hot it actually got.

So I used a donor radio which I remove the amp from to put in my main radio, however in order to remove it, the board needs to be unscrewed from the heatsink. However in order to get to one screw you will need to also remove the capacitor.

So first remove all the plugs (from the speakers, antenna and headphone jack PCB), unplug the lead going to the board at the bottom of the radio (see picture), next unscrew the board itself then leaver it up and unplug the large white connector (to the right of the photo).

In order to remove the capacitor you will firstly need to remove the adhesive holding it onto the board then you can flip the board over and de-solder it. The method I used was adding new solder to the pins (to make it easier to melt, using the same method to remove dried markers that won't wipe off, going over it with a fresh marker to make it then removable), once they are to their melting points I just kept going back a forth between solder pads with the iron and started wiggling the capacitor free (using light movements).

Once I removed the capacitor I then went onto removing the amplifier, I used the same method of adding new solder to the existing solder, once it had all melted in I went along it with a solder wick and removed as much of the solder as possible. Once I got most of it off I tried wiggling it out, when solder was left over I just heated it up with the iron until it came loose.

I figured while I had the amp off I may as-well replace the thermal paste, so I cleaned the heatsink and back of the new amp, added a couple pea-sized drops of thermal paste then inserted the amp back into the board, before I soldered it I firstly put the screws back in, wiped away an excess paste. Then proceeded to solder it, next I then soldered the capacitor back on (making sure it went on the same way it came off).

At this point you can re-attach the board back to the radio face. First clip on the large white connector then lever the board back down and screw it down, then re-connect the board at the bottom of the radio face.

Step 3: Find a 5v Source

After probing around the board I managed to find this jumper wire held a 5v source when the radio was turned on. Get a length of wire and solder 1 end straight to the 5v jumper wire.

If you are trying this on a different radio modal you may need to double-check this same jumper wire is producing 5v. So far the BMR102 and DMR102 did but I'd imagine if the circuit board looks very much the same it probably will also give out 5v, but might be worth double checking. In the event it may not give 5v maybe trying probing around some of the other jumper wires to see if there is another that gives 5v.

The whole idea I had with this project is I didn't want to manually switch the module on/off and especially didn't want it always powered on (when a battery it connected, despite the power state of the radio). So my goal was to find a power source on the board that would either produce a 5v source to directly power the module, or if I could only find 12v (or above) I'd use a relay and step-down board for the model.

Step 4: Hooking Up the Audio Source

I figured I'd go ahead and use the AUX2 board, located inside the battery compartment. As seen in the first photo I've put it's resting spot on the next "slot section" over, so when the Bluetooth module now sits is where the AUX2 board was. So removing that, flip it over (second photo) go ahead and solder 3 wires onto the board as shown, black it obviously used for ground, white is the left channel, and yellow is the right channel.

In order to trigger the AUX2 input on the radio, I 3D printed a plug (included the STL) to go into the audio socket. Without the plug the radio won't switch over to AUX2. (I was going to find a more permanent way, but I figured I'd just go this route). If you don't have access to a 3D printer you could either use mostly any plastic plug (or just anything nonconductive). You might be able to use a toothpick (maybe, not tested), or the alternative I was going to go with was just chopping the plug off an old aux lead and just plugging it into it.

No matter what you use, just make sure it's secured in enough to not fall out. The plug I designed is tight enough to not cause damage but tight enough where it won't fall out.

Step 5: Next Soldering Up the Bluetooth Module

Simply just follow the picture, 5v RED to positive, ground BLACK to negative on the power terminal and the speaker terminal, left WHITE to left channel and right YELLOW to right channel.

Step 6: Mounting Boards

I just used double sided tape on the Bluetooth module and pointed it in a way so I can look through the hole where the AUX2 port would be to check the module status indicator.

I then utilized the spare slot next to where the AUX2 board was, turned it 180 degrees around flipped it over.

Step 7: Finalizing Install

Go ahead and plug everything back in, the antenna, speakers and the AUX2 board. I then figured I'd zip tie a few cables to further tidy it up.

Re-attach the face, 4 allen key screws on the front and 2 philips screws inside the battery compartment.

Step 8: Enjoy!

Once back together, plug in a battery and you'll be able to check through the AUX2 hole in the battery compartment to see the light should be off, turn the radio on and only then you should see the light on the Bluetooth module start blinking. Then switch the radio over to AUX2.

Next on your device go into the Bluetooth settings and scan for the module. Depending on which one you get it might be named differently, but mine happened to be called "XFW-BT"

Step 9: Troubleshooting

Firstly it you are having any issues start by making sure you've plugged everything back in, back in it's correct spot and it's plugged in properly. Then proceed with the following steps. I've gone ahead and included a reference photo of where everything is originally plugged in.

No sound: If the rest of the radio (FM/AM) is working fine and the problem lies within the module, it could be simply a faulty module, faulty wiring. You can test this by partially disconnecting the module, weather you de-solder the whole board, and hook it up using a double-end aux cord and micro-usb cable and use either of the AUX inputs on the radio to see if there is any audio, you could possible even try a completely different speaker just to test the module.

If all else fails (nothing works) then I'd dare say it could be a faulty module. If only 1 AUX input works then, the other may be faulty.

If both AUX ports work, the module works. Then it could be a faulty wire(s).

Sound problems: If you're experiencing sound problems. Crackling/popping you may had short circuited the amplifier board, this is what happened to me during this project (hence why I had to replace mine). The give away for me was it became so hot I could barely touch it. So I figured I'd try swapping the amps over which fixed this issue for me.

Not switching to AUX2: Did you place something in the port to enable the AUX2 input? you may need to fiddle around with what you've used to trigger the input. Make sure what you've used is deep enough and a pretty snug fit, and that it hasn't fallen out.

If you still can't getting it to activate AUX2 for testing remove the battery, insert an AUX cord plug into the AUX2 port (don't worry about the other end of the cord) then re-insert the battery and try going to AUX2. If still nothing it may be a faulty AUX2 board, you may be able to visually see something wrong, double-check the wiring on the board (in step 4) you could check for continuity from the end of the AUX2 board plug to the actual audio jack on the board.

No power to module: The power source used in step 3 may either not be 5v or could be higher that 5v which if so could cause damage to the module. Get yourself a multi-meter and refer back to step 3 with finding a 5v power source.

If you are experiencing any other problems feel free to message me and I might be able to help.