[TenTec] Orion and amplifier fault

[Rick at dj0ip.de]

I'm progressing.

Here is an excerpt from an email from June 2005.

"They have found a noise emission in the LF-band, centered around 300kHz, at the Orion output, although at low level (he stated below 45dB to 100W). Unfortunately, its level does not depend on the output-power regulator setting. Most likely, it is the reason making ACOM protection to trip since ACOM is monitoring the LF band in order to detect any RF arcing.
We are thinking now about a HPF between the Orion antenna and the ACOM input."

Jack traced this to a voltage regulator on one of the boards.
Jack and I modified our own Orions, lifting a pin from the regulator and inserting a choke between it and ground.  As far as I know, we are the only ones who ever did this mod.   

A proper fix to the problem would have required a redesign of the printed circuit board.
Instead, a free LPF was given to all users who had this problem.

I'm still searching old files for the exact details, but I have several hundred thousand files.  ☹
Worse yet, maybe I only have it on paper, which means I would have to search through boxes of old papers.

73 - Rick, DJ0IP
(Nr. Frankfurt, Germany)
May the Sunspots be with Us!

-----Original Message-----
From: TenTec <tentec-bounces+rick=dj0ip.de at contesting.com> On Behalf Of Bruce Small
Sent: 10 August 2021 20:06
To: tentec at contesting.com
Subject: [TenTec] Orion and amplifier fault

I need to tap the collective wisdom of this group regarding an interesting problem.

I have an ACOM 700S solid state amplifier that is driven either by an Orion (565) or an Orion II (566).

When I use the 565, the amp faults on 10 meters only. The protection fault indicates high SWR and excessive drive current. This happens regardless of the amount of drive power from the Orion, even with the PWR control turned all the way down, providing about 6 watts of drive. 
On CW, the fault occurs on key-down, while on SSB and FT-8 the amp faults on key-up, at the end of a transmission. Engaging the TUNE button does not produce the fault. All bands other than 10 meters work normally.

Using the O II, none of this behavior occurs, and the amp plays happily.

Steps taken without solving the problem include:
*Replace coax jumpers  (they needed it anyway) *Replace arc plug in lightning arrestor *Remove all components from the signal path (watt/SWR meter, tuner, coax switch, lightning arrestor) and connect directly to the coax run to the antenna *Connect to a different antenna fed through a separate coax cable *Control the amp using Keying Loop 1, Keying Loop 2, or the Amp Key output
* I don't have a good oscilloscope, but to the best of my ability to observe, the CW waveform was well-shaped and didn't show any spikes in power.

All of this points to an issue with the Orion on 10 M - what else should I look at?

Thanks & 73,
Bruce KM2L

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