Trace only works at 5V/div

JmU
Posts: 7
Joined: Sun Mar 19, 2017 12:14 pm

Trace only works at 5V/div

Post by JmU »

I´ve soldered correctly the DSO 150. The traces works only at 5V/div correct (it seems also at 50mv).
What can be the reason?
jye1
Posts: 1221
Joined: Wed Feb 20, 2013 4:58 pm

Re: Trace only works at 5V/div

Post by jye1 »

Please check signal SENSEL0 - SENSEL2. These signal might be stuck at 0V.
JmU
Posts: 7
Joined: Sun Mar 19, 2017 12:14 pm

Re: Trace only works at 5V/div

Post by JmU »

What values needs to be at this measure points?
jye1
Posts: 1221
Joined: Wed Feb 20, 2013 4:58 pm

Re: Trace only works at 5V/div

Post by jye1 »

Set the scope to different sensitivity and measure the voltages at the signals. Please see the attached table.
SENSEL[3-0]_Levels.jpg
JmU
Posts: 7
Joined: Sun Mar 19, 2017 12:14 pm

Re: Trace only works at 5V/div

Post by JmU »

Was a time offline.
I´ve checked the voltage. Everything as it should be.
Attached you can see the change of V/div. at 5V and 50mV the signal is correct. All others are noisy.
What can be the reason?
I can´t use this device like it is now!
jye1
Posts: 1221
Joined: Wed Feb 20, 2013 4:58 pm

Re: Trace only works at 5V/div

Post by jye1 »

Can you post clear photos of the board?
JmU
Posts: 7
Joined: Sun Mar 19, 2017 12:14 pm

Re: Trace only works at 5V/div

Post by JmU »

Hello,
here the requested files.
Attachments
IMG_1951.JPG
IMG_1952.JPG
jye1
Posts: 1221
Joined: Wed Feb 20, 2013 4:58 pm

Re: Trace only works at 5V/div

Post by jye1 »

Thank you for the photos. The photo quality is great.

When you checked the voltages of SENSEL0 - SENSEL2 did you check them at the main board or at the pins of U3? How the noise look like? It looks you forgot to post pictures in your earlier post. Also, how are the power supply (AV+ and AV-) voltages?

From what you described the issue is related to U3.
JmU
Posts: 7
Joined: Sun Mar 19, 2017 12:14 pm

Re: Trace only works at 5V/div

Post by JmU »

The measure points you can see in the picture DSO150.
The other pictures shows parts of the video I tried to attach in a previous mail.

AV- --> -5.97V
AV+ --> +6,96V
Attachments
DSO150 2V.png
DSO150 5V.png
DSO150 10V.png
DSO150 20V.png
DSO150.png
jye1
Posts: 1221
Joined: Wed Feb 20, 2013 4:58 pm

Re: Trace only works at 5V/div

Post by jye1 »

Thank you for the photos. If you can please try a different power supply? It is better to use linear PS. We saw similar cases that happened on some switching mode power supplies.
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