Input is massively attenuated

[tazziedave]

Hi

Having assembled the Shell I have the following Voltages:

Code: Select all

Vsup   9.01V
V+     8.17V
Av+    5.11V
V-    -7.61V
Av-   -5.04V
V1     2.9mV
V2    -0.8mV
V3     5.3mV
V4     1.69V

The test signal (shown on another oscilloscope) is as follows

0.1V Test signal on other scope

3.3V Test signal on other scope

on the Shell it looks like:

0.1V Test signal on Shell

3.3V Test signal on Shell

No amount of adjustment on C3 and C5 made any difference.

Any suggestions?

Thanks

Dave

[jan]

Dave ,

see my post "C5 calibration on new version"

use the settings from the manual , c3 can affect both settings ( 0.1 and 3.3 ) c5 has very low influence.

[jye1]

@Dave:

In the photos the couple switch was set to GND. Please change it to DC and check again.

[tazziedave]

Yep, was the couple switch - obvious really. Just hadn't changed it after doing the Vpos alignment.

Maybe the manual could have a quick reminder in the adjusting section.

Thanks for your help.

Dave