[Hallicrafters] SX-100 Lower SideBand Problem

[DW Holtman]

I'm in the middle of trying to get my SX-100 working. I have the following problem.

UpperSidtband (USB) works great, LSB will not work at all. The LSB (1600 khZ) will not oscillate.

I did the following with no clue why it does not work. 

1. Removed the Sub-chassis and connected it with jumpers so it will operate next to the radio, so I can trouble shoot it. 

2. Switched crystals, both crystals oscillate in the USB slot and neither oscillates in the LSB slot. 

3. Measured voltages and resistors on the stage, (12AT7) everything checks normally. 

4. Measured the inductance of the top and bottom of T9 (. They both adjust from about 20 to 50 uH. The USB crystal (bottom) turns on around 33 uH, adjusted the LSB (top) for the same, will not oscillate. Tried to adjust the top (LSB) many times and the stage will not oscillate. 

5. Swapped tubes twice and tested on a tube tester. 

6. It is getting its ground from the "Response" control switch (Green Wire). 

7. The only difference that I can find is the capacitance from the Cathodes of the oscillators (Dual Triodes) . USB reads .009 uF to ground; the non-working LSB reads .007uF. I don't think this would not allow it to oscillate. 

I'm running out of ideas. Any suggestions would be greatly appreciated. 

Thank you, 

DW Holtman 

WB7SSN