[skykng]

I  have a nice Model 90 Loboy that I have rebuilt that plays very well below 1100khz. It has one 47 audio final.  I've never had one that was dead at the high end - if at all, they were dead at the low end.  I have tried four different 27 osc tubes, traced the osc coil to be correct resistance and intact, checked all the related caps and resistors, voltages are: p2-plate 75vdc, p3 grid at  high end -14vdc and -27 at low end (600khz), p4 K is 2.7vdc.  Radio aligns well at 175khz.  Sure would appreciate some ideas as to why it is dead at the high end.  Symptom: bone dead from 1600khz down to around 1200khz when it starts picking up static and noise.  From 1200 on down to 550 it is loud and clear.  Variable capacitor has been cleaned and peaks well at all four trimmers with no shorts.  Osc trimmer dead above 1200khz with no signal heard from sig gen.  New one for me.............Thanks very much.............Steve