Jim, I agree with the others, Ten Tec stuff is prone to cold-solder joints,
however usually the the bad joint can be isolated my bouncing and tapping
the rig and circuit boards until its found.....my Corsair II had one in the
High-IF board and drove me crazy until I pulled the board and and
re-soldered every stinkin' connection and now finally fixed!
73......./k6sdw
>From: "Jim Reid" <kh7m@hsa-kauai.net>
>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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