Looking for some help and hope maybe this thread will help others in the future. I have repaired a Zenith 25MC33 chassis to working condition. I would like to go through the exercise of alignment, or at lease the motions to see where it is at. I understand care is needed and there is risk of making things worse. With that out of the way I have the SAMS folder and the Zenith CM-106 service manual, also the B&K 415 instruction Manual.
I am trying to start with IF and Trap alignment but immediately am stuck. Probably a simple setup mistake but so far I get no measurable signal on the oscilloscope. Making changes to the B&K 415 has no affect.
Per the instructions here is what I have done:
- Grounded the 3 test points
- Nothing is connected to the tuner and set it in-between channel 3 & 4.
- Feeding signal from the B&K 415 via the direct probe to test point G
- I have tried with and without the resistor/capacitor assembly as per the Zenith directions
- Note this is the only connection from the B&K 415 as I have highlighted in yellow below
- I tested the B&K 415 cable end to end and it measures approx. 10K resistance on both the ground and signal clips
- Oscilloscope is connected to test point C1
The last pic is measuring at test point C1 while operation normally with a cross hatch video signal.
B&K 415 Setup
Zenith CM-106 Directions
Scope:
