Bush VHF61 - magic eye not closing.

[ms660]

Originally Posted by Vectis68

The grid voltage has increased from 0.5mv to 2.1mv when tuned to a station.

The cathode voltage has increased slightly from 4.8v to 5.0v when tuned.

There shouldn't be any cathode voltage to speak of WRT chassis/ground because the cathode should be connected to chassis/ground.

What's the DC voltage WRT Chassis/ground at test point "A" in the schematic when tuned to a decent FM signal ?

Lawrence.

[Sideband]

Originally Posted by ms660

There shouldn't be any cathode voltage to speak of WRT chassis/ground because the cathode should be connected to chassis/ground.

Absolutely!! The cathode should be at chassis potential. Make sure it is the cathode you are measuring (pin 2) counting clockwise from the gap. If it is pin 2, try connecting a piece of wire between pin 2 and chassis. It could be nothing more simple than a high resistance earth tag causing all the trouble.

[ms660]

I reckon that's meant to be the anode voltage.

Lawrence.

[Vectis68]

Apologies for not commenting sooner, I am currently unable to boot my laptop and so I've had to reset my password so I can login here on my phone.

I reckon that's meant to be the anode voltage.

Lawrence.

You are correct, that is the anode voltage. My mistake.

Phil.