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eHam Forums => Amplifiers => Topic started by: 6Y5TR on March 10, 2010, 05:03:32 PM



Title: al80a no grid current
Post by: 6Y5TR on March 10, 2010, 05:03:32 PM
There is no ip current when the amplifier is keyed and yes you here the clicking of the relay when the amp is keyed .There is also voltage on the center top 2.4v.


Title: RE: al80a no grid current
Post by: W8JI on March 10, 2010, 05:29:13 PM
There is no ip current when the amplifier is keyed and yes you here the clicking of the relay when the amp is keyed .There is also voltage on the center top 2.4v.

If there is no idle current and you had idle current and grid current before having the transformer repaired  twice, you need to measure the dc resistance (power off) from the center tap to the filament wires. Also trace that path back to the relay and zener and make sure you have not disconnected a wire.

That would be a good first step.

Your problem is someplace in the filament center tap system.

73 Tom