[bdi1976]

Hey guys....I've been troubleshooting the 90 (1-47) for awhile and need suggestions.  Problem=no signal or volume control UNLESS I ground either side of trimmer#11 to ground, then full clear signal returns with volume control as well. 
 I've checked:
1. 80 tube and ecaps read good.  All coils are intact...HOWEVER 2nd RF has 2 coils from #5: the one to RF grid is good (6 OHMS).  The other runs from #5 to secondary of 1st RF.  THIS ONLY SHOWS 0.1 OHMS....is this open?? SEE ATTACHMENT OF SCHEMATIC
2. All tube filaments/plates/ screen grids are close to spec's except 1st AF PLATE is HIGH=150vdc (spec= "45")
3. Alignment acheived a weak signal at max for 1/2/3
4. ANOTHER OBSERVATION: Cathode of DET.RECTIFIER = 0 very dc (spec=17v).  I noticed this leads to the 1St IF secondary where I can manually ground the circuit and it works perfectly...I think this is a clue.
.....all other cathodes read 1-3 v, but spec's show 18-24v.  I've seen in other posts that say 2-3v are normal....is this true?  Not sure why such a discrepancy exists if this is true. BC RESISTOR -connection-3 reads the same, 2.5v, which supply most cathodes
Although my 4th set I'm still an amateur and greatly appreciate any help...thanks guys
Mark