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[AMPS] FAILURE OF PARASITIC RESISTORS IN AL-811X AMPLIFIER

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Subject: [AMPS] FAILURE OF PARASITIC RESISTORS IN AL-811X AMPLIFIER
From: fredffff@hotmail.com (Fred Fliss)
Date: Wed, 01 Mar 2000 01:28:05 EST
Hairy Green Toads from Mars made Lee Roberts say:

"This is the second amp that I've bought from Ameritron and it will
"be the last. The first amp is a solid state amp whose finals kept
"blowing.  Ameritron blamed it on my TS450. So, I'm an unsatisified
"Ameritron customer. Apparently others aren't too happy either. AND,
"* shouldn't have to modify an amp to make it work properly.

"But, I think I'll replace the resistors with the metal oxide types.
"Maybe Ameritron should provide them for those of us still under
"warranty?

Lee, you may never feel good about this.  Several years ago, a chap I worked 
with had purchased a "3kW Super Tuner" from MFJ (who now owns Ameritron).  
He managed to melt several roller inductors, while using only a stock 
SB-220, hardly capable of 3kW under any conditions, let alone 1.5kW average. 
  (For those who care, he had a relatively modern HP spectrum analyzer on 
"peak hold" mode connected to the output of the amp after burning up the 
first tuner inductor - nothing outside the anticipated amateur emissions 
showed up, such as a VHF parasitic).  After the fourth roller coil, he 
called MFJ and insisted on speaking with the customer service manager, or 
someone else in charge.  He ended up speaking with a chap named Martin, who 
claimed to be the president.  After nearly an hour of discussions about what 
the specifications really meant, and what he should do, he came to this 
conclusion about Martin's opinions and position.

1)  No, we are NOT going to fix any defects or alter our design based on any 
problems you encounter.  Please do not suggest improvements to us because we 
have no business reason to listen.

2)  Just because the name says 3kW, does not mean it can handle 3kW in any 
measurable way.  If you purchase a Ford Escort, you do not expect the car to 
escort you anywhere, do you?  A name is only that, a name, it does not mean 
anything measureable.

3)  No, we are NOT going to fix any defects or alter our design based on any 
problems you encounter.

4)  We sell a lot of stuff.  If it breaks, some hams assume it was their 
fault and don't complain.  Others think it's our fault, and contact us.  We 
convince most of them it's their fault.  The rest, who we cannot convince, 
we offer refunds.

5)  No, we are NOT going to fix any defects or alter our design based on any 
problems you encounter.

I also remember in an amplifier comparison written up in QST, that an RF 
choke burnt up in the amp tested by QST.  In the QST article, they said that 
a call to Ameritron revealed that the design of the choke had changed since 
the ARRL acquired the amp.  The QST writer accepted that explanation, but 
did not order a replacement choke for testing.  Later, this same buddy of 
mine, working on an Ameritron amp of the same nomenclature as the one 
reviewed, had reason to call Ameritron.  He asked for information on how to 
identify whether he had the early or later design for the choke.  He was 
told that there was no design change, and that the QST writer had 
misinterpreted the telephone conversation entirely.

About two years ago, I was helping a fellow perform some experiments with RF 
heating.  In an effort to keep costs to a minimum, he had acquired ham 
equipment for his RF source, as opposed to expensive lab grade equipment.  A 
Yaesu transceiver and an AL-80B were the RF power source.  I figured that we 
could run the AL-80B at a reduced power of, say 300 - 400 watts CW (time 
periods for the experiement were ten minutes or so) without stressing it 
badly, since that power level is within the RTTY specs of the amp.

The amp came with the 3-500Z in a separate box.  We pulled the cover from 
the amp and installed the tube.  We popped the cover back on and connected 
everything up and tried to run power.  We got 100W out of the exciter, but 
switching in the amp killed the power, and we could not tune.  And, look, 
the tube is not lighing!  Off came the cover and we discovered that the 
wires to the filament pins on the socket had never been soldered, and one of 
them had fallen loose during shipment.

So much for Ameritron's quality control.  Seems to permeate design, 
manufacturing AND customer support.

If you and I are both disgruntled Ameritron customers, does that mean that 
there are gruntled customers?

Fred
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