Hello Benjamin,
Thank you for writing in and so sorry for the inconvenience caused on you.
Could you please tell us more details of your operation, such as the input voltage/current, the wiring, the load, the working environment?
Could you please tell us which fault LED is always on?
If you can, we sincerely hope that you can send us some images or video of the fault LED and the wiring 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.
Best regards

Hello henry,
Thank you for writing in.
Since many product are with similar titles, it is hard for us to ensure which product you are referring to.
Could you please send us the link of the product or the order ID if you have bought the product?
With your help, we can find a solution more quickly.
Beg your understanding.
Best regards

Hello Frank Palm,
Thank you for writing in.
Since many products are with similar titles, it is hard for us to ensure which product you are referring to.
Could you please tell us your order ID or the link of the product?
It is better that you can tell us more details of your application, such as the load, the working environment.
As you have said that “without adding any switching noise either up or down the power lines”, does the power supply will always provide 12V steady DC power or does the voltage will go down even lower than 9V?
With your help, we can find a solution more quickly.
Waiting for your reply.
Best regards

Hello Dane,
Thank you for writing in.
Since many products are with similar titles, it is hard for us to ensure which product you are referring to.
Could you please tell us your order ID or the link of the product?
It is better that you can tell us more details of your operation, such as the input voltage/current, the wiring, the working environment.
If you can, we sincerely hope that you can send us some images or video to let us check the problem details.
With your help, we can find a solution more quickly.
You can send an email (service at droking dot com) with this information.
Looking forward to hearing from you.
Best regards

Hello Jaime Castillo,
You’re welcome.
If you have any questions, please feel free to write back to us.
Have a nice day!
Best regards

Hello Al,
Thank you for writing in.
Here is a recommendation for you:
Part number: 200186
DROK® DC 3-21V Load Battery Tester, 35W 3A Portable USB Monitor, Intelligent Constant Current Electric Discharge Resistance Power Resistor Kit for Power Bank Capacity Testing Support QC2.0/3.0

TECHNICAL PARAMETERS:
Voltage Range: DC 3-21V (compatible with quick charging such as the Qualcomm QC2.0, 5V/9V/12V/20V, Qualcomm QC3.0, BC 1.2, MTK-PE and Apple 2.4A etc.)
Current Range: 0-3A continuously adjustable (roughly adjust 0-3A by per 0.1A , precisely adjust by per 0.01A)
Accumulative Capacitance Range: 0-99999mAH
Accumulative Electric Energy Range: 0-999.99Wh
Power Range: 0-35W( the continuous discharging power is less than 35W)
Accumulative Time Counting: 0-1000h
Voltage Testing Deviation: 0.01V
Threshold of Smart Temperature Control: when the temperature﹥55℃（131℉), the fan would automatically work; when﹤45℃(113℉), the fan would automatically turn back off
Detector of Smart Temperature Control: premium NTC thermistor
Switching Regulator IC Frequency for Fan: 1.2MHZ
Power Supply Indicator: blue light when powering on
Fan Speed: 6000/min, 40×40×20mm
Controlling Chip: constant current chip
Radiator: 6063 aerospace aluminum radiator, 40×40×10mm
Adjustment Potentiometer: durable metal potentiometer
Discharging Power Tube: voltage-controlled low-impedance MOSFET (more stable constant current when is on high voltage, high temperature)
Operating Temperature: ﹣10 ~﹢65℃ (14-149℉)
Product Dimensions: 100mm×48mm×30mm

WARM TIPS
When operating a burn-in test discharging, the resistor would get hot, about at 80-85℃, so please note not to be hurt by the heat.

Hope this can help you.
Best regards

Hello Mike G,
Thank you for writing in.
Here is the recommendation for you:
DATASHEET_090588
Hope this can help you.
Best regards