10-02-2019, 08:18 PM
The near identical sound receiver from the Baird T23 is now on the bench so that it can be compared with the unit from the T5.
The T23 unit performs much better than the one from the T5.
The oscillator frequency is 190.725Kc/s and is unaffected by either no signal input or the presence of the 41.5Mc/s TV sound signal. The sine wave amplitude on G1 of the MX40 is 30volts P - P, same as the T5 sound unit. Once again an FC4 octode was fitted in place of the MX40 and once again the result was no sound output. For some reason or other the demodulator will not operate with the Mullard FC4 octode.
At least we know the T5 loudspeaker is OK
Geordie McBoyne.
The T23 unit performs much better than the one from the T5.
The oscillator frequency is 190.725Kc/s and is unaffected by either no signal input or the presence of the 41.5Mc/s TV sound signal. The sine wave amplitude on G1 of the MX40 is 30volts P - P, same as the T5 sound unit. Once again an FC4 octode was fitted in place of the MX40 and once again the result was no sound output. For some reason or other the demodulator will not operate with the Mullard FC4 octode.
At least we know the T5 loudspeaker is OK
Geordie McBoyne.
