Display Runs - that's all

Hello Velleman Team,

today i have build your Oszilloskop EDU 08 and now i need some help.
I send you an Picture, the Display lights up so it works but there is no signal or anything else.
I hope you have some ideas for me.

Kind Regards

Khargaraa

As a first test you may check the voltages on SK1 connector on the top board.
Please see this thread for more info:
viewtopic.php?f=69&t=18057

Done!

Top row from left to right 3.33, 0, 0, 0, 0, 0, 3.32, 0, 0.55
Bottom row 0, 3.33, 0, 0, 0, 0, 0, 3.32, 0

These are my results.

The voltages seem to be OK.
The problem may be on the display board.
Please check all the display soldering joints for possible short or open.

You can also check the voltages on the points marked A-M in this picture:

The voltages should be about:
A=9.2V
B=8.2V
C=7.2V
D=2.0V
E=1.0V
F=1.6V
G=7.2V
H=1.6V
I=4.6V
J=9.8V
K=1.6V
L=3.3V
M=11.2V

It Runs! :smiley:
Thank you for the hint!

I’m glad to see you got it sorted out!

What solved it? I have the same problem: backlight from LCD is on, but no data on LCD. Voltages on SK1 are correct but voltages on the pins A thru M are way too low…

I bought a EDU08. After putting it together, only the backlight works, no data is shown. I bought another EDU08; maybe I made an error with soldering or overheated a part. Same problem. Now I have two EDU08’s which don’t work. The pins A thru M indicate voltages that are much lower than expected.
Can you help me or point me in the right direction?
A=2,7
B=2,4
C=2,2
D=0,7
E=0,5
F=2,4
G=2,4
H=1,6
I=2,4
J=2,6
K=1,6
L=3,3
M=2,7

The voltage on points F, G and I seems to be equal.
This may indicate a short circuit between these pins.
Points F, G and I are connected to adjacent pins of the display.
Possible solder bridge may be between the display pins…