05-02-2019, 11:18 PM
(This post was last modified: 05-02-2019, 11:20 PM by Geordie McBoyne.)
Work continues on the cabinet reconstruction but instead of discussing that part of the restoration let's concentrate on the electronics.
The later T5 models have an interesting sound demodulator. Instead of the usual diode half wave detector, a Mullard FC4 octode valve performs the demodulator function. The first two grids of the FC4 operate as a Colpitts type oscillator. The 41.5mc/s TV sound signal is supplied to grid 4. The resultant audio is developed acros the anode load and supplied to a Mullard 354V triode amplifier.
Has any forum member encountered this type of demodulator in a radio receiver?
Geordie McBoyne.
The later T5 models have an interesting sound demodulator. Instead of the usual diode half wave detector, a Mullard FC4 octode valve performs the demodulator function. The first two grids of the FC4 operate as a Colpitts type oscillator. The 41.5mc/s TV sound signal is supplied to grid 4. The resultant audio is developed acros the anode load and supplied to a Mullard 354V triode amplifier.
Has any forum member encountered this type of demodulator in a radio receiver?
Geordie McBoyne.