09-12-2022, 11:04 PM
(This post was last modified: 09-12-2022, 11:05 PM by Geordie McBoyne.)
The module in my set was fitted a few weeks ago and was working well supplied from a PP3 battery.
Yesterday, the power supply components were fitted. Components used are a NOS RS components 6V + 6V mains transformer and a very compact voltage regulator module. The module employs the PJ317 regulator IC which is good for 1.5amps so it has an easy time supplying power to the David Winter FM module. Only 50mA @ 10volts.
The receiver seemed to be working well on all three wavebands with little or no interference from the module on the medium waveband.
It is possible to power down the module's power supply by accessing the "V adjust" pin 1 of the PJ317.
The two 6volt windings will provide power for the dial lamps.
Well, that was yesterday. I was convinced there was no interference, but today when tuning in to TalkSport on MW there was a considerable amount of interference coming from the module.
No problems on LW.
The FM module must be shut down on MW.
This was achieved by reducing the module power supply to 3volts when switched to MW. The local oscillator waveband switch has a spare position on MW which permitted a 470ohm resistor to be connected to the "volts adjust" pin on the regulator IC. See attached circuit.
Geordie McBoyne.
Yesterday, the power supply components were fitted. Components used are a NOS RS components 6V + 6V mains transformer and a very compact voltage regulator module. The module employs the PJ317 regulator IC which is good for 1.5amps so it has an easy time supplying power to the David Winter FM module. Only 50mA @ 10volts.
The receiver seemed to be working well on all three wavebands with little or no interference from the module on the medium waveband.
It is possible to power down the module's power supply by accessing the "V adjust" pin 1 of the PJ317.
The two 6volt windings will provide power for the dial lamps.
Well, that was yesterday. I was convinced there was no interference, but today when tuning in to TalkSport on MW there was a considerable amount of interference coming from the module.
No problems on LW.
The FM module must be shut down on MW.
This was achieved by reducing the module power supply to 3volts when switched to MW. The local oscillator waveband switch has a spare position on MW which permitted a 470ohm resistor to be connected to the "volts adjust" pin on the regulator IC. See attached circuit.
Geordie McBoyne.
