Gerald, with bad band condx I'm not sure about the rx but always wondered if
there was something wrong there. I mostly operate 80 and 40m but I'm kind of
thinking about selling the rig and want it to be right. 20m and seventeen
share
the same filter in l.o. mixer so it could be that one of the switching diodes
or the ic that drives the diodes is the problem? On other boards the switching
is a little different. I really feel the problem is in the ic or one of the
diodes in the mixer board.
Thanks for your interest,
Wayne
P.S. I will get into it again next week.
________________________________
From: Dr. Gerald N. Johnson <geraldj@weather.net>
To: tentec@contesting.com
Sent: Sat, November 27, 2010 7:18:42 PM
Subject: Re: [TenTec] Omni 6+ - no output on 12M/10M and omni 6+/ power issue
Question is does it receive on those bands? The LO is as critical to
receive as to transmit and its the same LO. Loosing two bands on
transmit is indicative more of a low pass filter problem where those two
bands are shared like 10 and 12.
73, Jerry, K0CQ
On 11/27/2010 3:32 PM, Wayne Dial wrote:
> Ken, if I'm correct the output from the l.o. mixer , port 26, should be pretty
> much the same on all bands? I do have a good scope but do not have a good
> signal generator. I used to have all that quality equipment on the job, but
I
> have been retired from the business for 13 yrs. The l.o. mixer board is
nested
> below a cover which has another board mounted on the top, making it almost
> impossible, with out a wiring harness, to make live checks. I have made ohm
> meter check of of the switching coming into the board and all looks okay. I've
> checked the diodes at the output of of u2 feeding the bandpass filters and
they
> are all okay. I've not checked the solder joints. I do wonder about u2
> (udn2985, 8 ch. source driver) though it is rare to have that type of failure
> with a I.C. if it has not taken some kind of abuse.
>
> Thanks for the input and I will take the board out and check the solder joints
> with a magnify glass.
>
> Wayne
>
>
>
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