Low AM Modulation On President P300

Also same as Uniden PC 244 40 ch SSB

Sideband is fine. Loud clear 15 watts

AM carrier is fine. AM modulation is present but very low, around 10-20%. VR5 mod. adj has no effect. Mods sites also point to limiter being TR29 which is adjacent to VR5. Clip for more modulation. Clipped one leg and no effect either.

Anyone know what component may be bad causing low AM modulation on this unit?

Thanks