I should have offered this first: before suspecting the preamps, did you enable preamp control for each band in the 910's "SET" menu? Preamp control must be enabled before the front panel P.AMP button will switch power to the preamp. Also, there must not be anything inline such as an SWR meter, filter, or anything else that might block DC on the coax.
If you hook the preamp up to the rig with a short jumper cable, you should head a noticeable relay click from the preamp when you press & hold the P.AMP button.
George, KA3HSW
----- Original Message ----- From: "Mark L. Hammond" marklhammond@gmail.com To: amsat-bb@amsat.org Sent: Wednesday, March 17, 2010 5:29 PM Subject: [amsat-bb] Devices in Icom preamps AG-25 AG-35
Hello all,
We either had two bad preamps to begin with, or they became casualties during transport to K4T, but regardless--the Icom preamps we took appear to have bad GAsFET devices in them.
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