[TenTec] Orion and amplifier fault

[Rick at dj0ip.de]

Well lets say mitigated the fault.
The cause of the fault can be eliminated . . . if I remember correctly . . .
by raising the pin to ground of a 7808 regulator and inserting a small choke
between that pin and ground.

I have been searching my old files for 15 minutes, but haven't found it yet.
Somewhere I have it marked in a schematic and have a photo of it after I
modified my own Orion.

But, as Barry said, the Hi-Pass filter works just fine.
But they're not cheap.

If I manage to find the mod, I'll post it.


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
Barry N1EU
Sent: 10 August 2021 20:21
To: Discussion of Ten-Tec Equipment <tentec at contesting.com>
Subject: Re: [TenTec] Orion and amplifier fault

There was a similar, but not quite the same, issue where the original 565
caused arc fault errors in Acom amplifiers.  The 565's bipolar PA output
transistors seemed to be the cause and the problem disappeared with the 566
that used different (FET) output transistors.  The work-around back then was
to use a high pass filter between the 565 and the Acom.  That eliminated the
arc faults, which seemed to be related to low frequency spurs in the 565 rf
output.

73, Barry N1EU

On Tue, Aug 10, 2021 at 11:06 AM Bruce Small <brucesmall73 at gmail.com> wrote:

> 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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