Hello all,
Right now I have a defective SI-9110 differential probe,
Input 6Vdc,
the problem is no -12V, +12V is normal.
I checked the waveform of Pin15, the PWM of +12v as attachement.
But Pin 10 no any waveform.
If using external -12v instead, this differential probe works properly.
So the only problem is the DC-DC chip.
But the factory erase all chip mark.
I have draw the schematic of this part,please see the attachement.
The length of this chip is 1cm.
The bottom marked"NBK" and have a "Philippines" mark.
I hope some one can tell me the model of this chip.
Maybe this chip also used on other type differential probe.
Thanks & Best regards