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White Screen Issues

Posted: Tue Mar 06, 2018 6:06 pm
by minatorn
I bought a DSO138 and soldered all the parts to the board and now I am getting a white screen. I have listed below the voltage at each test point. Can anyone help me find the problem?
Input 9.38 AV- =-5.002 AV+ = 4.953
+3.3v = 3.262 +5v = 4.984 D1 = 0.148
R38(L)= 6.385 R38(R)= 8.370 R39 =-1.406
OSC = 1.927 TP22 = 3.263 R40 = 0.816
D2 = 9.380 V+ = 8.600 V- =-8.290
V1 = 0.053 V2 = 1.616 V3 =-2.857

I tried holding the soldering tip on each pin at J1 as well but that didn't help.

Re: White Screen Issues

Posted: Tue Mar 06, 2018 6:18 pm
by minatorn
I forgot to upload pics of the board. Thanks in advance

Re: White Screen Issues

Posted: Wed Mar 07, 2018 6:02 pm
by jye1
Did you see the LED blinked at power up? If you did that means MCU was running. The issue is likely caused by poor connections between MCU and LCD. It is suggested to check the soldering of pin-headers that connect the two boards. Re-solder each pin if necessary.

Re: White Screen Issues

Posted: Wed Mar 07, 2018 6:39 pm
by minatorn
Yes the LED blinked twice at start up and when I tried test mode the LED blinks slowly. I will try re-soldering and update later.

Re: White Screen Issues

Posted: Fri Mar 09, 2018 5:23 pm
by minatorn
I heated and reflowed the solder on each point at J1 and J3 on LCD board as well as J1 and J8 on Main board then did continuity tests on each pin of the both 40 pin headers and still can't find the problem.