19-08-2021, 09:35 AM
I have been tracing out some of the circuits on the 'scope. it uses a three valve puckle timebase, feeding a long tailed triode pair tube driving amp.
The Y amp is a single valve feeding a cascade pair of pentodes to drive the plates.
By operating the push buttons on the front the Y amp can be bypassed and the input signal fed directly to one of the Y plates.
There is no provision for trace flyback blanking, unusual as it is easy to add with the circuit used.
What I can't understand though is the addition of some diodes in the Y amp plate bias network, I have never seen anything like it before.
Can someone suggest what is the purpose of the diodes. they look as if they would perhaps do some kind of level shift or clamping.
The diodes are a point contact variety of some kind, there are no markings.
See attached photos:
KInd regards, David.
The Y amp is a single valve feeding a cascade pair of pentodes to drive the plates.
By operating the push buttons on the front the Y amp can be bypassed and the input signal fed directly to one of the Y plates.
There is no provision for trace flyback blanking, unusual as it is easy to add with the circuit used.
What I can't understand though is the addition of some diodes in the Y amp plate bias network, I have never seen anything like it before.
Can someone suggest what is the purpose of the diodes. they look as if they would perhaps do some kind of level shift or clamping.
The diodes are a point contact variety of some kind, there are no markings.
See attached photos:
KInd regards, David.
