ZXY6005 buttons malfunction

[malekblbl]

I have a ZXY6005 Buck Converter, it was working really well until suddenly buttons stopped working properly, in fact it seems like they swap functions.

ZXY6005 have 5 buttons "UP / DOWN / <-> / SEL / OK" but now its all messed up.
UP is still UP
DOWN is performing UP
<-> is performing DOWN
SEL is performing <->
OK is performing SEL

I don't know if it's a software or a hardware problem, as per the attached schematic it may be the 3.3v supply or a resitor connected to the buttons, just guessing.

does anyone had this problem, you help is much appreciated.

[rg58]

It's basically just a simple voltage divider. The controller meassures the voltage on PIN 11 and is translating this into a function.

1) Check 3.3V near R41
- TURN OFF -
2) Check R41 = 1MOhm - pull-up resistor for PIN 11 = High (unlikely the cause, but check it anyway)
3) Check R42 = 10kOhm
4) Confirm resitance between R42 right side (3.3V) and R49 (left side=GND) is 10.4kOhm (or less)
5) Double-confirm R43 right side to R49 left side (GND) is 400 Ohm

I assume either the 3.3V are too low OR R42 has gone higher OR a problem with the soldering between the resistors of this voltage divider. Can you see that the key is performing the function that the previous key (further left in the schematic) was supposed to do? A sign of lower voltage which corresponds to the function of the other key (as evaluated by the controller on PIN11).