Hi Jim
You probably have one of Ten Tec's famous cold solder jounts. I just fixed my
Scout that was at Ten Te c last fall for a problem with the 12 meter module not
seating properly. I got it back in December but did not use it until I finally
went to put it in my van for mobile use. I tried it out on the bench and it
would not transmit. After trying everything I opened it up and was playing with
those tiny little coax connectors when I found an intermittent in one of them.
I found that the socket on the circuit had come loose from the circuit board
with a cold solder joint. I touched it up with the iron and it works fine. I
have an RX-325 receiver that wouldn't receive and after sending it back to ten
tec only to be told they could no longer repair it, I opened it up and checked
every component on every board and found two cold solder joints. This seems to
be a recurring theme with Ten Tec and their various radios. The Omni V was
famous for them. So if your hearing problem comes and goes I would check the rf
connections and just wiggle things around and see if you can find the problem.
Its very rare for an actual component to be bad. Most actual component failures
occurr in the infancy of the rig if they are ever going to occurr. Use your
schematic and follow the card to card connections to see if you have a solder
problem. It may save th postage back to TT. Good Luck
--- Jim Reid <kh7m@hsa-kauai.net> wrote:
>
> Hi to all,
>
> Well, now am absolutely convinced my Corsair II is occasionally
> not hearing too well, particularly low level CW signals
> are NOT heard/copied that are just fine on both the
> Triton 544 and Omni VI+! The RF preamps in each of
> these rigs differ from one another. I am going to assume
> that is the site of the problem as all else seems fine in
> the Corsair.
>
> In the Corsair II, the RF preamp is Q3 on the RF Mixer board,
> #80987; this is a simple transistor. In the Triton, the RF
> preamp is a dual gate MOSFET, while in the Omni VI+, the
> RF preamp is a group of low NF grounded gate configured
> FETs. Or, the RF front ends are different in each of these
> TT rigs.
>
> Now, my Corsair II was at TT back in August, '00 for a number
> of fixes, PTO rebuild, etc. -- the complete TT Service Dept.
> treatment! A month after receiving it back out here in Hawaii,
> I had to return it again as the transmitter wouldn't transmit.
> The no charge fix that time was reordering the low level driver
> board connections, reset the ALC, and signed off as tested
> on all bands.
>
> I am sort of convinced that this radio, now some dozen or so years
> old, is suffering from "old age" at least as far as traveling around
> via Fed Ex goes! So am reluctant to return it once again to
> Tennessee, as it was there only 7 months ago.
>
> All the CW beacons on 15 and 10 meters are easy to hear/copy
> today on both the Omni and Triton; on the Corsair -- silence,
> only the hiss of noise. Stronger CW signals can be heard,
> for example the K5 land beacon up at 28280, and many SSB
> signals on 10 meters. Other indicator about the Corsair is
> a very seldom moving S meter; again an indicator, I believe
> of only low level RF/IF signals getting to/through the IF/AF
> board # 80984 on which the AGC and S meter circuitry lies.
>
> Another point, this "partial deafness" seems to be there
> at one time, and not at another. For example, when
> I started this note, the "deafness" was in place. After
> nearly finishing this note, I have come back to the
> Corsair, and it now seems to be hearing weak signals
> again!!
>
> I suspect that the problem may not be the RF amp transistor,
> Q3 on 80987, but maybe a joint/connection which is
> "occasionally" not good; maybe temperature sensitive,
> or to a slight jiggle of the operating table (though this is
> pretty heavy and stable). or......?? Assume this joint
> problem would be on, or near the 80987 board, true?
>
> Even on a very, very weak signal, the signal to noise ratio
> still "hears" to be better on the Triton than when using the
> Corsair, even in the apparent "good" state of operation.
>
> Too bad it is not a tube rig, and I could just pull and
> change tubes, hi.
>
> May have to call TT service dept. again, phooey.
>
> 73, Jim, KH7M
>
>
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>
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