help repair dealsens ps5 v2

Hello everyone!

I’m facing a serious issue while repairing two game controllers with BDM-010 and BDM-020 boards. I want to describe the situation in detail in hopes someone has faced something similar and can offer advice or solutions.

Controller 1 (BDM-020 board):
After connecting the batteries, one battery immediately starts blinking repeatedly (3 times in a cycle).
After cleaning, there was a short circuit somewhere, and now it blinks continuously without stopping when connected via USB.
There were glitches — the LED backlight sometimes flickered bright and dim, and the right trigger vibration motor activated spontaneously.

Controller 2 (BDM-010 board):
When connected via USB, it also blinks 3 times and then stops.
I re-soldered the 3D sticks (TMD Genful), after which it stopped being recognized by PC and PS5. The desoldering and soldering were done carefully without overheating. It worked before but had heavy drift issues.
One stick was sticking — it didn’t always return to the zero position, as if it was stuck. Possibly flux got inside the stick during soldering. Later, yellow liquid was coming out from under the trigger.
I cleaned it with medical and technical alcohol, after which the stick started to “click,” but after some time it stuck again.

Now I’ve removed both sticks, but the board still doesn’t boot properly; it blinks 3 times when connected to USB and then stops.

I’ve been checking continuity from ground, USB, and the IC — I suspect some circuits are damaged or shorted.
Resistance measurements and continuity tests on the board haven’t given clear results yet.

Questions and help needed:

• Has anyone encountered this 3-blink error and complete failure to initialize after resoldering sticks?
• What are the main circuits and contacts I should test and check on BDM-010 and BDM-020 boards?
• How can I properly test the batteries if one of them immediately starts blinking upon connection and the other doesn’t respond at all?
• Any tips on repairing the ICs or soldering on these boards without causing permanent damage?

Thanks in advance for any help or advice!