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Re: [Amps] Anyone Recognize These Components?

To: <>, <>
Subject: Re: [Amps] Anyone Recognize These Components?
From: "slifamily" <>
Date: Thu, 15 Jun 2006 18:20:10 -0400
List-post: <>
The circuit on the left appears to an optocoupler with a MOSFET for current
amplification.  The circuit on the right appears to diode bridge detector.
This could be a circuit for switching bias when the input signal is present.


-----Original Message-----
From: [] On
Behalf Of
Sent: Thursday, June 15, 2006 7:43 AM
Subject: [Amps] Anyone Recognize These Components?

I recently purchased an early (Pre MFJ) inoperable Ameritron AL1200
amplifier realizing full well that it was extensively modified with
components and circuit alterations that would be difficult to decipher.
Hopefully, there's someone out there that can identify the two part
component board depicted in the digital before I remove it. The PC board
appears to be professionally etched. There is no antenna changeover relay
and the large black coax wire in the foreground connects directly from the
pi-net output to the antenna output SO239. Lots of cut wires and no
recognizable method for bias control. I would cautiously assume that this is
some method of pin diode control. The amp is not functioning for a variety
of reasons so it's impossible to assess if this circuit was working or
simply a failed attempt at some modification. All the mods appears to be in
the antenna changeover circuit Any comments would be appreciated. Ron

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