Several HF transceivers have had overshoot problems, including other
ICOMs. Yes, the IC-7410 is repaired by ICOM for no charge. However,
this is the same policy with the TS-590S. Kenwood's ALC Update Program
is absolutely free-of-charge, including return shipping. Later
production runs of the TS-590S, as well as the new TS-590SG units do not
have any ALC overshoot problems. My TS-990S does not have any ALC
overshoot, as well as my TS-590S which was updated by Kenwood East at no
charge in June.
73
Don W9CW
On 12/18/2014 9:14 AM, Jim W7RY wrote:
Is he (YOU) SURE it was parasitics? More likely hot switching of the
amplifier T/R relay. This causes LOTS of problems that folks THINK are
parasites.
After I install my QSK system into amplifiers, the arcing completely
STOPS because the relays are no longer hot switched.
ALC overshoot spikes also cause arcing in amplifier capacitors. Mostly
Kenwood has ALC overshot including the TS-590S.
Although, the Icom IC7410 has ALC overshoot problems on SSB. Which is
repaired by Icom for free. Although only the units made before mid
2014 are affected.
73
Jim W7RY
-----Original Message----- From: Bill and Liz
Sent: Thursday, December 18, 2014 6:49 AM
To: amps@contesting.com
Subject: [Amps] THE SKINNY ON MY AL-82
I recently tracked down the ham who had done work on my AL-82 as well
as a second one purchased at the same time by another fellow who was
forced by health out of ham radio. I learned that right from the get
go both amps had parasitic problems and hardly a day would go by
without one or the other having an “event” (hence the original owner
had two of them!). These amps date from the 90s-perhaps they were of
the initial design before changes started being made.
The Measures parasitic retro kits were installed in both amps and the
problems immediately disappeared. Both amps today have the same minor
problem on 10M: extreme heating, discolouration and distortion of the
100 ohm paralleled resistors in the suppressors but no parasitic events.
From this information it would appear that I would not be wise to
re-install the original suppressors, and, since I seldom run the amp
over 400W on 10M anyhow, that I should “let sleeping dogs lie” as it
were.
Thanks to all who came forward with ideas and advice.
Bill VE3NH
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