I just received a new 2017 generator and everything seems to work fine with the exception of the motor drive.
Is anybody familiar with this instrument and can assist with troubleshooting?
Here is what I found so far
- the service manual is here:
https://dl.dropboxusercontent.com/u/28207218/marconi%202017/prodpdf_784_1.pdf- The motor control circuit is on page 301 and the description is on p.81
- I have checked that the motor is not burned out (12 ohms)
- After selecting the frequency on the keyboard the generator switches to the correct range, however the Motor Drive Enable(-) signal which is supposed to start the motor does not go to Low.
The correct frequency can be set by manually adjusting the tuning knob.
It seems that the next circuit to trace is somewhere on the filter/processor board but I'm now a bit lost