XB1 controller works fine but no LED white light, mixed PCBs

[sidgallup]

I got this controller from someone that thought it didnt work because the LED light never comes on and the rumbling motors were disconnected, however after tests, it works perfectly fine on battery and also USB cable, the only thing its lacking is the LED withe light, it never comes on either via battery or USB cable.

i swapped the LED diode from a donor board that i confirmed was working and it still wont come one, and the LED diode i removed from this controller worked fine on the donor PCB.

After inspectiona nd almost going insane, i noticed they are not PCBs from the same revision, the charging board is from the first model 1537, number  X860655 011, and the joystick board its from a 1697 model, number  X901912 008

Is this why LED isnt working?  ive read these boards are not compatible, but this combination is working perfectly fine except the LED light. Dont know if the issue is with combining these boards from different revision, or maybe theres something damaged on the power board.

Any help appreciated.

[RDC]

The 1537 and 1697 are pretty much the same thing, no reason that LED shouldn't work.

You can check R10 and Q3 on the power board, but you mentioned the Rumble motors, and if those are also not working then I'd suspect U2 or something around there keeping it from working as all it really does is power the LED and Rumble motors. 


1537 - https://acidmods.com/forum/index.php/topic,43204.0.html

1697 - https://acidmods.com/forum/index.php/topic,43725.0.html

[sidgallup]

The 1537 and 1697 are pretty much the same thing, no reason that LED shouldn't work.

You can check R10 and Q3 on the power board, but you mentioned the Rumble motors, and if those are also not working then I'd suspect U2 or something around there keeping it from working as all it really does is power the LED and Rumble motors. 

thanks for the reply... ive been testing for shorts around the U2 area and everything seems correct, ive replaced U2 IC with one from a donor board that has a working LED light, but still i get no white light.
I noticed the main board is getting really low voltage to R10, its getting 0.6v and after R10 and into  Q3 its getting 0.3v which seems lower than expectede.
So ive been tracing continuity from R10 to pin2 on the J2 connector and its fine, then connecting the joystick board, i get continuity from R10 on the power board, to TP45 on the joystick board so i assume theres no broken trace here, if im not mistaken, after TP45 that trace goes under the U1 IC chip so im not sure how can i test if its a broken solder ball under U1.

Is there any other point on either board that i could put a jumperwire directly into R10 just to test if it lights up? on a working controller i can see R10 should get 1.2v, is this correct?

[RDC]

Those voltages on R10 are fine, it's not turning on the power to the LED per say, that is just the signal from the MCU to turn on Q3 (thru R10) that then turns on the Ground side of the LED. It's a PWM signal (around 1kHz and 20% duty that you would need a scope to see) so a DMM isn't going to show you the full 3.3v there, only around 0.6v or so, but that seems good from your measurements.

Is R5 good? It should have 3.5v on one side and around 3.2v on the other. If there is no 3.5v on R5 then the U2 circuit is suspect, or something in the Rumble circuit is possibly dragging that voltage down. If there is no 3.5v on R5, you can remove Q10 on the top board there and that will eliminate it being anything to do with the Rumble circuit. If the 3.5v is still missing, then it's U2 or one of it's support components. If the 3.5v comes back, then I'd suspect U4 or U5 on the bottom board is shorted internally.