Here goes........have patience with my probing.
What type of power supply you using? It should current limit at about 20
amps. A 30 to 40 amp or higher rated supply can allow the radio PA to draw
excessive current and damage will result under certain condition where the
PA load impedance is very low. Fuses simply aren't fast enough to protect.
Is your power supply protected for over voltage? It should be and should
shut down at 15.0 volts.
Is the power supply negative connected to the chassis of the Omni via a
separate ground and not just the negative power lead? It should be.
Is the power supply negative connected to chassis of the power supply? Some
power supplies {name with held} float the negative and are prone to RF
getting into the voltage sense circuit and allowing an oscillation to take
place in the supply. Can spell trouble for the radio.
Are all pieces of station equipment connected together back to a common
point such as the power supply via separate dedicated ground cables.
Should be.
Regarding the tuner, do you use the radio to adjust the match or do you have
a bridge like and Autec or MFJ to set the match?
{The best antenna tuner that money can buy, used incorrectly, is no better
than a cheap tuner.}
Is the meter used to measure SWR in the tuner, or an external meter, or the
one in the radio. Coax cables between the devices can cause the SWR to look
good at one place and produce a very poor match at another location in the
system. This can be due to a bad cable or poor connector installation or
loose connector on the SO-239.
In my case I use a 238 tuner with its internal SWR/Power meter, a Daiwa
CN-801 SWR & Power meter, and the SWR meter in the radio. In adjusting the
tuner I switch in and use an MFJ antenna bridge. Then switch the radio into
the system. In all cases, with power, all three SWR indicating devices will
show the same and correct SWR reading. I have seen installations where SWR
at 3 places will be different. This indicates circulating RF and that can
give false SWR indications. Hope you don't have this condition.
Parts for the Omni VI and VI Plus are basically "off the shelf" parts. Be
assured that Tentec Service is fixing the radio, taking it through a 24 hr
burn-in and it is working when it gets to you. Hate to say it, but
something in your station or your method of tune-up is causing a problem.
Get me some more information and I'll dig into it further.
73
Bob, K4TAX
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