28-09-2016, 02:53 PM
(This post was last modified: 28-09-2016, 02:53 PM by Geordie McBoyne.)
Hi Frank, Hi Jeffrey,
many thanks for you input about the modulator problems.
Some good news about the Pineapple converter. The video amplifier part is supplied from an 8volt source, or it should be. The two resistors associated with the LM317 regulator had changed in value, thus reducing the supply to just under 7 volts. Also, there was a 15ohm series resistor between the 20 volt supply and the input pin of the regulator. I've reduced it to 10ohms. So now we have exactly 8 volts for the video amplifiers and what a difference that has made. No more sync crushing. For test purposes the modulator part of the Aurora is being used to supply 405 line signals to the TV receiver.
The modulator chip is indeed a fourteen pin device. For some reason or other the chip is buried in some sort of wax compound.
Geordie McBoyne.
many thanks for you input about the modulator problems.
Some good news about the Pineapple converter. The video amplifier part is supplied from an 8volt source, or it should be. The two resistors associated with the LM317 regulator had changed in value, thus reducing the supply to just under 7 volts. Also, there was a 15ohm series resistor between the 20 volt supply and the input pin of the regulator. I've reduced it to 10ohms. So now we have exactly 8 volts for the video amplifiers and what a difference that has made. No more sync crushing. For test purposes the modulator part of the Aurora is being used to supply 405 line signals to the TV receiver.
The modulator chip is indeed a fourteen pin device. For some reason or other the chip is buried in some sort of wax compound.
Geordie McBoyne.
