If an component fails due to over-drive in order to protect other parts in the
circuit, that sounds like that item is functioning as A FUSE.
Further, as a devastated former 9500 owner with this problem, twice, I can say
that any product designed to have an SMD resistor ...in a ham radio product...
which works as a fuse is bad design. Technicians in their lofty labs can cope
with SMDs , but not me, Mr. Point-to-Point wire man. Yes that resistor should
have taken several hits before failure, but not for me.
I did not want to publicly slag on Alpha (that Alpha company, not the current
one) too much, but the real cause of that tiny resistor to fail was from inside
the 9500 which changed its programs at its own whim. I set it up with correct
input and outputs and tuned them all as per instructions. Then in what
appeared to be normal operation, the 9500 would just select something else,
causing the problem.
The three parallel disk capacitors coming off the output of the tube were
UNDER-SPEC-ED and failed in normal operation. The under-specifications is
proven by the fact that Alpha, upon my complaint, offered a higher rated cap on
their spare parts list. Those better caps appeared on Alpha parts list the day
after my complaint. The technician I consulted said the first caps had been
giving trouble "back to 76."
That same (name-with held to protect the nice) technician told me that the 9500
should come back to the factory about EVERY THREE YEARS.
Now, before I nail anyone for telling me I don't know what I am talking about,
I sign off as perhaps the most UNsatisfied Alpha customer ever.
Charly K4VUD
________________________________
From: Amps <amps-bounces@contesting.com> on behalf of BRADLEY FOCKEN
<BFOCKEN@msn.com>
Sent: Thursday, October 13, 2016 7:42 PM
To: Mike & Becca Krzystyniak; amps@contesting.com
Subject: Re: [Amps] Alpha 9500 Owners: Question on Overdrive resistor.
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@msn.com
________________________________
From: Amps <amps-bounces@contesting.com> on behalf of Mike & Becca Krzystyniak
<k9mk@flash.net>
Sent: Saturday, October 8, 2016 7:50 PM
To: amps@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
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++++++++++++
-----Original Message-----
From: Amps [mailto:amps-bounces@contesting.com] On Behalf Of Charles Harpole
Sent: Monday, February 17, 2014 6:33 PM
To: amps@contesting.com; lrrbst@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@hotmail.com
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