TEX-20 FM Exciter VCO Loss of Lock

May 8, 1996

PROBLEM: Field reports have been received that some TEX-20 units will operate for a period of time and then suddenly the front panel L.O. Unlock LED will come on, permanently or intermittently.
This causes loss of power of output.

SOLUTION: Voltage regulator U2 (78L02) located inside the shielded case on the main board was omitted on some units and a wire jumper installed instead. Under certain conditions fluctuations in the regulated 15V supply will cause the oscillator to unlock.
Installing the missing regulator will solve this problem.