[TenTec] Omni C Questions ( Maybe OT )

[Curt]

Thanks for the info.  Yes, the power switch is no big deal, can you 
elaborate further on the "switch pins" would this be on the 80711 Osc-Mixer 
board?  Did you remove it to do the soldering?  How?

Further the high current problem.  On CW, everything seems to work fine and 
high current is not an issue.  On SSB, keying the mike produces 12 amp 
current draw, but no output power until microphone spoken into.    So, 
carrier balance doesn't seem to be the issue.  And, since CW doesn't exhibit 
high current I'll conclude PA isn't an issue.  I'm suspicious about C16 on 
80718 SSB board, which is a 4.7M electrolytic

----- Original Message ----- 
From: "Al Gulseth" <wb5jnc at centurytel.net>
To: <tentec at contesting.com>
Cc: "Curt" <rhulett1 at consolidated.net>
Sent: Tuesday, February 22, 2011 9:24 AM
Subject: Re: [TenTec] Omni C Questions ( Maybe OT )



On Tue February 22 2011 8:16:03 am Curt wrote:
> Having bought an Omni C from a ham in NY who claimed it had no operating
> issues, found my trust in fellow hams is sometimes misplaced.
>
> I have a few questions about the issues identified (so far):
>
> Power switch won't stay "on". My Omni D/B is push for "on", which matches
> the manual's description for this Omni C, this one is pull for "on", but
> will drop to "off" unless something isn't wedged between the switch knob
> and panel. Did Ten Tec change the sense of the power switch with the Omni
> C?

The switch may have been changed out at some point in its life. They are a
known trouble spot. The easiest way around it is to put a jumper across the
switch contacts and use the switch on the PS.

>
> Only one of the 10M positions ( 28.5) has a crystal. None of the WARC
> positions has a crystal. My Omni D/B has all 10M positions filled, and 30M
> functions on receive. More troublesome is that the band switch seems
> "flaky", with the display changing to 1.0000, requiring rocking the switch
> to restore normal frequency. Is this a known issue with these rigs?

>From the www.qsl.net/tentec/specs/546c.jpg Omni C ad: "All 9 hf bands --  
only
crystals are needed for the 18 and 24.5 MHz bands." I'd say that all of the
10M crystals should have been there from the factory as well as the 30M one.
As to the band switch, rather than cleaning being needed, it could instead
need resoldering on the crystal section. I went through that a few years 
back
on a Corsair that would die after it had been operating for a while. (I'm
guessing here that the physical architecture of the Omni C is very close to
that of the Corsair in this case.) I called TT repair and they recommended
checking the solder issue. Sure enough, there were hairline cracks around 
the
_square_ switch pins of the crystal section which were in _round_ holes on
the PC board. A quick "slurp" of the pins with the solder sucker followed by
resoldering cured the problem and the Corsair was still going strong when a
buddy of mine across town caught me in a weak moment and convinced me to 
swap
it to him. (The "square [switch/pot/relay] peg in a round [PC board] hole"
issue is not unique to TT - I've also dealt with it in older automobile
electronics and test equipment to name just a few other places.)

>
> Most troublesome, on SB-N, keying the microphone causes the indicated
> current on the TT-255 to run up to about 12 amps constant, even though the
> ALC isn't lit and regardless of ALC or drive setting. Talking will cause
> the ALC to blink on voice peaks but the current rises until the TT-255
> trips. ( The SWR is 1:1 ) Would this indicate that the carrier isn't being
> suppressed, problem with the SSB Generator board? Anyone else had similar
> experiences they successfully solved?

it might be a carrier suppression issue, but it might be a PA bias issue. 
Or,
(hopefully not) bad/shorted final(s)?

73 es GL with this one, Al

>
> I bought this rig because wanted 30M capability and spare potential. Maybe
> the rig has too many issues to meet those goals.
>
> 73, Curt KB5JO
>
>
>
> _______________________________________________
> TenTec mailing list
> TenTec at contesting.com
> http://lists.contesting.com/mailman/listinfo/tentec