Found and fixed the problem - turned out there was a hairline (more like
microscopic) trace shorting on the input side of the filter board that
shouldn't have been there. Cleaned it up with the exacto knife and all is
well again.
For the record, George at InRad was extremely helpful and concerned about
the problem. I've heard from another user of the add-on board who had a
similar problem, so there must have been a minor quality control problem
during a run of the circuit boards.
73
-Marty NW0L
martyt@pobox.com
At 02:45 PM 12/2/00 -0600, Marty Tippin wrote:
>Hoping someone can help me with a problem I'm having:
>
>I have a FT-920 with the InRad add-on filter board, which allows selection
>between either a single SSB filter or two in cascade. In my case, I have a
>2.1KHz and 1.8KHz filter on the board. I also have an InRad 400Hz narrow
>CW filter installed.
>
>Prior to installing the InRad add-on board, I had only the 400Hz Narrow
>filter and a 2.1KHz Inrad SSB filter installed. When operating in RTTY
>(DATA / USB) I was able to select the 400 Hz filter as expected - however,
>after installing the add-on board, nothing happens when I select the
>narrow filter - that is, there is no change in received bandwidth. On CW
>mode, the narrow filter works just like it always did.
>
>The add-on board is a minor installation task - it has two coaxial leads
>that solder in place of the on-board SSB filter, and two more leads that
>provide power for switching between the boards.
>
>To test my theory that the problem is caused by the add-on board, and at
>the suggestion of George at InRad, I disconnected the coax leads from the
>add-on board and soldered them temporarily to the stock Yaesu SSB filter.
>At that point, the narrow filter worked again in RTTY mode. This would
>point to a problem with the add-on board, but the board functions normally
>when in SSB mode so I'm not sure how that could be the case.
>
>Looking for anyone else on the list who has this same combination of
>filters (including the add-on board) to compare notes. Any other
>suggestions would be appreciated as well.
>
>Thanks & 73,
>
>-Marty NW0L
>
>--
>FAQ on WWW: http://www.contesting.com/FAQ/yaesu
>Submissions: yaesu@contesting.com
>Administrative requests: yaesu-REQUEST@contesting.com
>Problems: owner-yaesu@contesting.com
>
>
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