Hello, I was given a NordicTrack 1750 treadmill with a non working touchscreen console. I took it apart and from what I can see, there is a problem with the display portion of the console. Nothing comes on. I took the display board apart and started testing the tiny components and I would like some advice. The board that controls the touchscreen appears to be based on an Samsung ARM Cortex 8 design. I am unable to find the schematics for the board, so I it is hard for me to properly diagnose the issue. Plus I am no electronic expert, I understand the basic functions of the various components, but that is pretty much it. I poked around the board and from what I can understand, I have a 12v input which goes into NB634 mosfet that provides some 9v and 5v to the system. From what I can gather, the mosfet works as it should since I am getting some 5v and 9v ouputs (See pictures). I followed the circuit to a MAX8698CEWO that should be providing most of the high power/low voltage to the CPU and other ICs and I think that my issue is with this PMIC. I took some measurements from the pins that I have access to (see pictures) and I can see the 5v on IN1 through IN6 but I get only 1 LDO line with a 3v output (LDO1). All the other LDOs aren't providing any voltage that I can measure. When I poke around the board, I can find some 5v at certain points but no 3v anywhere else. I did find some 1.2v near the CPU but that is it. I get no 3.3v for the display or any voltage for the memory and flash. My question is, can the issue with the lack of 3v coming from the PMIC be cause by a failed PMIC or can it be something else? Also, if the PMIC is bad, Is there a way to know if the PMIC was used with the default settings or if the LDO output settings were changed?
Thanks Thanks.Maxim-Integrated-MAX8698CEWO-T_C2682647.pdfNB634 datasheet.pdf