How to Repair HC-06 or HC-05 Bluetooth Module

A lil about HC-06

Features:
HC-06 is a Bluetooth module that you can hook up with Arduino for small range serial communication. It allows your device to both send or receive the TTL data via Bluetooth technology without connecting a serial cable to your computer. Works with any USB Bluetooth adapters.

Default Baud Rate: 9600,8,1,n
Built in antenna
Coverage up to 30ft ( I dnt think so but its in spec sheet ) ( 10 feet in real life scenario with usb bluetooth 2.0 adapter )

Specifications:

Bluetooth version: V2.0+EDR

Operating voltage: 3.3V

Default Baud Rate: 9600,8,1,n.

Signal coverage: 30ft

Item size: 4.3 X 1.6 X 0.7cm

Item weight: 3g

Package size: 9 X 3 X 1cm

Package weight: 8g

Tools required to repair the module :

Soldering iron
Wire
Digital Multimeter

Step 1: Diagnosing the Issue

The first step is to check if all the connectors are okay.
Test the pins and soldering joints by DMM ( setting it a beep and making sure it beeps depicting the connections are okay )
If the joints are okay the second thing to check is your voltage regulator ( In my case this was faulty and mostly its the thing that gets faulty either due to high input or if you mix VCC and GND of the module)

How to check the voltage regulator ?

Give VCC and GND connections to your Bluetooth module. I gave 5V from Arduino UNO and used one of the ground.
Set your DMM to voltage and check the voltage of the regulator as shown in the pic. Black wire of your DMM at GND and red wire of your DMM at Vout. If the DMM shows voltage less then 3V then its definitely regulator that is faulty. If it gives more then 4V then again its faulty.
In my case it was 0.6V thats why one of the LED was litting up dim like shown in the pic above.

What if voltage regulator is fine ?

Like i said before its 80% the chance that voltage regulator will be the culprit. But if its not then most probably either of the 2 ICs on the module have died and believe me if an IC goes dead even intel can't repair it.

Step 2: Solutions

These are the solution that can help you with a faulty voltage regulator.

If your soldering skills are good replace it with the same voltage regulator
If you can trust a voltage source that can give 3.3V with good accuracy and stability like 3.3V on the Arduino UNO you can directly give that 3.3V to vout of the regulator.

I went with option 2 and soldered a small wire at vout like shown in the picture. Then inserted that wire's other end to 3.3V of Arduino and the module switched on perfectly.

Now when my HC-06 is on it gives a solid red light and a blinking blue light ( ready for connection). Before it was just a dim red light.

In picture as the LEDs are very close the red and blue light merges and gives a violet/purple kind of shade as you can see in pics.

Extras

I threw one of the module a year back because then i didn't know it was such an easy fix :/

If any of you are following me and expecting the CNC build update i am really sorry to say that the Work is around at 60% with y axis rail at 90% and currently is at halt state. The issue is that i got these small projects that i have to do to earn as i dnt have a job right now so it will take some time. But as promised what ever i have done i have took a lot of pics to make a good guide that will help many i hope.

Also dnt hesitate to ask a question or questions or correct me if you found a mistake :)

Peace