White Screen

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Posts: 2
Joined: Thu Mar 07, 2019 1:54 pm

White Screen

Post by Doragonfighter »

My problem is, I just see a white screen when I give the power supply of 9 V to the Osci.

The LED normally blinks two times at the beginning, also after I press RESET.
The voltages on the board are all near the reference voltages.

In the test mode the LED blinks slowly, so it should mean that I may have any open at port pin what should be connected.

I checked the voltage signals on the pins of the screen board. I checked, that on pin 2, 4, 22 and 36 are a voltage of 0,82 V, like on the measure spot on R40.
But on these ones should be measured 0 V because they are not connected in the circuit plan.
When I check the voltages of the pins without putting the screen board on the mainly board, all voltage signals are correct.
So that must mean I have some shorts on the screen board.
I also checked with my multimeter, but there is no wrong short at the pins on the screenboard.

Do anyone have a clue?
Thanks in forward for reading this and think about it.
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