[Amps] Alpha 9500 Owners: Question on Overdrive resistor.

[BRADLEY FOCKEN]

Hello Mike and Becca,

 The 9500 does not have a resistor that is a fuse for over drive. The resistor Charles is talking about is a 100 ohm resistor under the bottom choke on the controller board. It is an 0805 in older units but is 2512 in the newer unit.

 The resistor happens to blow when over driven because it is a filter and current limiter for the processor to keep RF off the line and limit the 5 volt current when the amp is keyed. If you are getting a fault 6 on the amp, I would look at the resistor the coil or the caps associated with the resistor.

 The 9500 does have over drive protection. It will drop to standby if the drive or gain are out of limits. It the current limit is reached it will shut the amp off. But like all products it will take the over drive only so many times before something will fail. It is impossible to design a product the will take abuse forever.

 People should not give advice who have no idea how the device works. Always call the manufacturer. It could be hazardus to your health if you get to the wrong areas and touch the wrong thing.



Brad Focken K0HM
bfocken at msn.com




________________________________
From: Amps <amps-bounces at contesting.com> on behalf of Mike & Becca Krzystyniak <k9mk at flash.net>
Sent: Saturday, October 8, 2016 7:50 PM
To: amps at contesting.com
Subject: [Amps] Alpha 9500 Owners: Question on Overdrive resistor.

Greetings

    I am trying to locate this SMD overdrive resistor that Charles mentions
in #2 below.

    I looked through the schematics provided in the manual and I am not
seeing it.
    Does anyone have more specific detail on its location or which board
this SMD fuse resistor is on?  Or even a picture of its location?

Many thanks in advance.

73's  Mike K9MK/5

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-----Original Message-----
From: Amps [mailto:amps-bounces at contesting.com] On Behalf Of Charles Harpole
Sent: Monday, February 17, 2014 6:33 PM
To: amps at contesting.com; lrrbst at yahoo.com; Martin Sole
Subject: [Amps] Alpha 9500 quirks

Please pass this info to Alpha 9500 owners.........

1.  Mine may be unique, but the foam piece between the mount for the blower
and the bottom chassis may be deformed or become deformed which will throw
the axis of the squirrel cage and reduce air flow.  Really deformed foam
will allow the axel to go so far off alignment that the cage will strike the
housing and make a noise.  The foam is deformed by the shipping hold-down
screw--the one to remove during first installation--and in my case, the foam
did not expand upon release of the screw.  After a few hours of usage, the
cage began to hit the housing, requiring replacement.

2.  The Alpha 9500 advertising description led me to believe that the amp
had over-drive automatic shut down protection.  That is, if it is driven
with more than about 100 watts, the amp will protect itself automatically.
Yes, it does that, but the way it functions is to cause a one watt resistor
to blow that is mounted on the rear circuit board.  That resistor is a tiny
SMD which will be beyond most old hands to repair.  Thus, the "protection"
against accidental over drive is a resistor working as a fuse located in a
very difficult place to replace.  The caution to owners of this amp is NEVER
to overdrive it, accident or otherwise, because the repair is not easy nor
quick;  the resistor is not a fuse that one can just pop in.  I was fooled
by the advertising description and was not super careful.

3.  There is a small light on that board that blinks red.  It is supposed to
do that.

I now fear what other unknown tricks and flaws await me using this very
expensive amp.  73,

Charles Harpole
k4vud at hotmail.com

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