[RFI] RFI from an Alpha 87A linear

van fair giw at bellsouth.net
Sat Jan 20 00:49:01 EST 2007

MY 4 year old alpha 87A amp has developed the ability to produce RFI which radiates into the air. I can receive the real raspy signal on a handheld battery powered SW rcvr set to SSB 100 feet away. The signal occurs all across the band on any band. For the most part it only produces the signal when the power switch is in the High position. IN the low power position it will spit and spurt for a few seconds when you go from high to low but then dies out and does not come back unless you go to high power or actually transmit. It does it when the amp is in standby or operate mode. NO exciter is required but it does it during a transmission or standby. It does not affect how the amp works except you cant hear because of the RFI when not transmitting.  

The sound I hear is commensurate with an arch occurring. I suspect a component in the power supply area but it is very difficult to trouble shoot this rig because  the computer built in it will hard fault and shut down  the amp if you disconnect components and turn it on. 

Anyone ever see this or have any idea what is happening in the 87A  or any amp. . thanks Van

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