Hello Paul,
You’re welcome.
Could you please send us the product link of DROK FJ40D12A10 so that we can ensure which product?
Best regards

Hello Shannon,
Thank you for writing in.
Have you connected a load to the output of the board?
If yes, what is the load?
Could you please send us some images of your wiring and the working environment to let us check the problem details?
You can send this information to us by email (service at droking dot com).
With your help, we can find a solution more quickly.
Looking forward to hearing from you.
Best regards

Hello Ramachandran,
You’re welcome.
Here is an image that we think it is useful to you:

Hope this can help you.
Best regards

Hello Paul,
Thank you for your interest in our product.
Here is a recommendation to you:
Part number: #180080
DROK DC-DC Adjustable Buck Voltage Converter Stabilizer 6-32V to 1.25-32V LCD Display Constant Volt Amp 6V 12V 24V Step Down Voltage Regulator Power Module with USB Port Protective Shell

Parameters：
Input voltage: 6~32V
Output voltage: 1.25~32V (Input must be 1.5 higher than output.)
Output current: Max.5V, adjustable, recommend the use of within 4.5A. (Over 2A or 35W, please enhance heat dissipation.)
Constant current needs above 2V output voltage, then can be adjusted. Only in the status of constant current can current adjustment work.
Output Power: Max. 75W (recommend the use of within 50W, please reduce power if the dropout voltage is large)
Operating temperature: -20 ~+70℃
Operating frequency: 180KHz
Conversion efficiency: up to 96%
Short circuit protection: Yes
Input reverse polarity protection: None
Over-temperature protection: Yes (Automatically shut off the output when over-temperature.)
Connection: terminals or solder terminals; VIN is input; VOUT is output
Module dimension: 65.6 x 40 x 25mm

Voltage-calibration Method:
In the case of power off, press and hold the “SET” key and power on, then enter into voltage calibration mode, and LCD screen starts to flash, release the “SET” key;
press “SET” and “ENT” key to increase or reduce the voltage to the right input voltage. It will automatically saves after 2s, then power off and the calibration is complete.

Current-calibration Method:
Suitable for no-load with current display or slightly large current. In the case of power off, press and hold “ENT” and power on, then enter into current calibration mode and LCD screen starts to flash, release the “ENT” key; press “SET” and “ENT” key to increase or reduce the voltage to the right value. It will automatically saves after 2s, then power off and the calibration is complete.

Please note that if you want to use this product in your application, you need to enhance heat dissipation.
Hope this can help you.
Best regards

Hello ArneS,
Thank you for your quick reply.
Could you please send us a video of your testing to let us check the problem details?
With your help, we can find a solution more quickly.
Looking forward to hearing from you.
Best regards

Hello Tom Fisher,
Thank you for writing in.
So sorry that we cannot find the product by DROK part # X000MC5S7.
Could you please check the part # X000MC5S7 again or tell us your order ID so that we can ensure the product?
Waiting for your reply.
Best regards

Hello Grant,
Thank you for writing in.
So sorry that the 3.5mm audio input jack cannot be removed.
Hope you can understand.
Best regards

Hello Bruce,
Thank you for writing in.
Could you please tell us your order ID or the link of the product so that we can ensure which product you bought?
With your help, we can find a solution more quickly.
Looking forward to hearing from you.
Best regards