30khz span
VBW 100hz
RBW 1khz
Center 27.205
Sweep 150ms
Attenuation 30db
Reference 0.0dbm
Mode - FM - No modulation
All settings same as above.
Mode - FM - Modulation applied
Note: mic gain wide open, power mic wide open, AMC wide open, deviation wide open.
Looks basically like an AM signal. Not seeing any of the deviated spikes as a normal FM signal would show on the analyzer.
Analyzer used:
Agilent E4411B
Attenuation - 30db
I've noticed that the C90 (supposed to be 100uf) I replaced with a 220uf is tied in with the PLL and vco, which also ties in with the deviation VR. Maybe that 220uf is too much for that circuit.
But still trying to track it down.
Mic amp shows proper voltage.
Audio IC shows proper voltage.
Balanced modulator shows proper voltage.
PLL synthesizer shows proper voltage.
Tx mixer shows proper voltage.
AGC shows proper voltage.
New Passthrough regulator.
New AF regulator.
New modulation transistor.
New 8v regulator.
Tried a new AMC transistor (TR32).
All 10v up to 35v caps replaced with nichicon brand.
AM modulation great.
SSB modulation fine.
FM modulation (deviation) almost non existent.
Receive in all modes is great.
All other functions work.