27-09-2017, 08:50 PM
Hi.
Well as I don't have a suitable LOPT as yet I have been doing some other things on the chassis.
Originally I cobbled in a rather large transformer to supply heaters to the CRT which has a 600ma heater. I have a nice neat little 12v transformer rated at 1.2 amps continuous, I have a "gold" 10 watt resistor of 10 ohms as a dropper, not ideal but neat enough for the job.
I have run up the set today less the line output stage and re-fitted the line blocking transformer I used initially, it is now stable with no drift. I also have been able to work out the values of the charging cap for 180, 240 & 405 lines. I have also found a suitable switch for line system switching.
I'm hoping to finish these mods before working on the line output.
What I did try today was feeding the frame stage from the 555 timer I used for the scope. Disconnecting the frame blocking oscillator transformer and using both triode and pentode of the frame ECL80 gives a good waveform on the scope from the output transformer. This was my intention initially but until I have line scan and EHT its somewhat hard to tell if this would be a success.
I am noting all the changes down on paper and once complete I will post up the full circuit.
Well as I don't have a suitable LOPT as yet I have been doing some other things on the chassis.
Originally I cobbled in a rather large transformer to supply heaters to the CRT which has a 600ma heater. I have a nice neat little 12v transformer rated at 1.2 amps continuous, I have a "gold" 10 watt resistor of 10 ohms as a dropper, not ideal but neat enough for the job.
I have run up the set today less the line output stage and re-fitted the line blocking transformer I used initially, it is now stable with no drift. I also have been able to work out the values of the charging cap for 180, 240 & 405 lines. I have also found a suitable switch for line system switching.
I'm hoping to finish these mods before working on the line output.
What I did try today was feeding the frame stage from the 555 timer I used for the scope. Disconnecting the frame blocking oscillator transformer and using both triode and pentode of the frame ECL80 gives a good waveform on the scope from the output transformer. This was my intention initially but until I have line scan and EHT its somewhat hard to tell if this would be a success.
I am noting all the changes down on paper and once complete I will post up the full circuit.
