06-05-2011, 01:01 AM
Presumably, the 'scope probe you were using to examine the waveform on the grid of the osc. valve was a high impedance - usually achieved by using a 10:1 probe - otherwise if it was a 1:1, the probe's capacitance could have stopped the osc. from running.
Another check is by using a high-impedance voltmeter, check for a negative voltage at the grid of the osc. valve. If a negative voltage is missing . . . it isn't oscillating!
What freq. range does the set cover? 6 ~ 18 Mhz, the 'usual'?
And what type of aerial are you using?
Al.
Another check is by using a high-impedance voltmeter, check for a negative voltage at the grid of the osc. valve. If a negative voltage is missing . . . it isn't oscillating!
What freq. range does the set cover? 6 ~ 18 Mhz, the 'usual'?
And what type of aerial are you using?
Al.
