Mike, there's a misunderstanding somewhere.
I've said from the get go that there must be 10w coming out of the LLD
board.
I have often connected the LLD of a Triton directly to the LPF board and run
10w QRP for a contest.
Scott already tried connecting the LLD directly to the LPF and he got
peanuts out.
He has a problem in a much earlier stage.
What we need to know is the power level expected going into the LLD.
I have never measured that and have no idea what it is.
Scott needs to get in there with a scope and start checking the
amplification, stage by stage.
Can't remember who said this earlier, but "Outza has to be much higher than
Inza" for each stage.
I HIGHLY RECOMMEND THAT SCOTT UNSOLDER THE WIRE SUPPLYING THE +12V TO THE
FINAL STAGE, AND NOT RECONNECT IT UNTIL HE HAS 10W COMING OUT OF THE LLD.
Connecting the LLD directly to the LPF will give the LLD a good enough
impedance match to be able to check the earlier stages.
Of course if there is a problem in the LPF stage, that could be distorting
our results.
It would be worth a try to connect the output of the LPF directly to a watt
metter/dummy load.
It's easy enough to do. Most likely the Omni has an RCA Phono plug on the
end of its LLD output coax cable.
That's very easy to extend outside of the box.
The input to the PA module is roughly 50 Ohms so your suggestion to connect
a QRP rig is a good one, but I would not do that yet. We've already
ascertained that the LLD is not delivering what it should, so Scott needs to
start there in the earlier stages.
What would really help now is to have a good working Omni to compare signal
levels with, but using a scope, not a volt meter.
73
Rick
-----Original Message-----
From: tentec-bounces@contesting.com [mailto:tentec-bounces@contesting.com]
On Behalf Of Mike Bryce
Sent: Thursday, February 16, 2012 4:23 PM
To: Discussion of Ten-Tec Equipment
Subject: Re: [TenTec] Low (to no) Power Out Omni D--han'nt given up yet
Rick,
Scott, is right.
Although you are getting two watts from the PA, you need to have more from
the LLD.
The fact that you're not drawing current indicates you're not making the PA
work. If you were drawing current and nothing was coming out, then you'd
have a shorted transistor or two.
It is still possible that you have a failure in the PA, but those
transistors are a bear to get to.
When an solid state PA is assembled, it's built from the pcb upward like a
building is assembled from the ground up. If one or both of the transistors
are bad, then you have to un-assemble the entire PA to get to the bottom
transistors. It's labor intensive and after you're done, right now it's a
crap shoot as to wether or not that's the problem.
This weekend I'll pull one of my Omnis out of the pile and measure the LLD
power into a 50 ohm load and I'll see about getting some wave form photos
from the scope,
Now, I know this is a long shot, but if you had someone near by with a
defunct triton 4 the pa is damn near the same as in your omni, a quick swap
would tell you volumes.
Or...
do you own a qrp rig?
disconnect the omni's PA from the LLD and inject 3-6 watts into it from the
qrp rig. Key the omni and you should see 30 to 60ish watts. (make sure
you're one the same band!)
what you did would be to use the qrp transceiver as the LLD and allow the PA
to to its thing. Yeah, there's all kinds of impedances mismatches, but it
will work.
Mike, wb8vge
On Feb 16, 2012, at 9:53 AM, Rick - DJ0IP / NJ0IP wrote:
> Scott, rather than second guessing, or waiting for Paul to read this
thread
> by coincidence and offer suggestions, why don't you compose a list of
> specific questions and call or email them to Ten-Tec.
>
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