DSO-138 Calibration not possible
Posted: Mon Sep 11, 2017 3:46 pm
I have assembled the DSO-138 from YVE-Tech. Very good building instruction! All functions of the DSO138 are available and are working well.
Problem:
Calibration is not possible. On the test signal there is a strong spike of the rising edge and also on the descending edge. Refer to Probe Calibration Figure B "Too much".
This can not be fixed by turning the Trimmer C4 and C6! Any turning on C6 / C4 is without noticeable influence on the overshoot.
The circuit for the calibration SEN1 = 0,1V, SEN2 = X5, CPL = AC / DC, with the resistors and capacitors has been tested several times by me and is fault-free.
Is it possible to get some advice to solve this problem?
P.S.:
In the circuit diagram the value = 220pF is given for C2, while the kit C2 contains the value = 330pF. This is in contradiction to the user manual 7. Ceramic Capacitors and the circuit diagram "CPL" C2 = 220pf. What is right?
Greetings Ottmar
Problem:
Calibration is not possible. On the test signal there is a strong spike of the rising edge and also on the descending edge. Refer to Probe Calibration Figure B "Too much".
This can not be fixed by turning the Trimmer C4 and C6! Any turning on C6 / C4 is without noticeable influence on the overshoot.
The circuit for the calibration SEN1 = 0,1V, SEN2 = X5, CPL = AC / DC, with the resistors and capacitors has been tested several times by me and is fault-free.
Is it possible to get some advice to solve this problem?
P.S.:
In the circuit diagram the value = 220pF is given for C2, while the kit C2 contains the value = 330pF. This is in contradiction to the user manual 7. Ceramic Capacitors and the circuit diagram "CPL" C2 = 220pf. What is right?
Greetings Ottmar