[Wswss] WW7D/R's FT-857D 2 meter issue

Sun Apr 7 18:44:46 EDT 2013

Darryl; first of all remember that it will take very good soldering skills and the proper tools to replace a surface mounted transistor. It could be tested with a very small probe for proper voltages, or by injecting a signal into gate 1 and then the drain to see if there is any gain.

In the past Yaesu parts have been inexpensive and delivered quickly. I've done a lot of repairs on ham gear, and unlike Kenwood, Yaesu still carries it's own stock of parts.

Good luck finding and fixing the problem.

Stuart K6YAZ
West Hills, CA

-----Original Message-----
From: n6ze <n6ze at aol.com>
To: wswss <wswss at mailman.qth.net>
Sent: Sun, Apr 7, 2013 12:53 pm
Subject: [Wswss] WW7D/R's FT-857D  2 meter issue

-----Original Message-----
From: Darryl J. Holman <djholman at u.washington.edu
During last Monday's VHF sprint, it became apparent that my FT-857D went 
somewhat deaf on 2 meters SSB and CW.   Subsequent testing (using 
calibrated equipment) shows that it receives fine on all bands except 2 
meters.

Two meters has lost something around 14db in FM and CW.   A full reset 
did nothing.   I'm guessing that the 2 meter front end is not working.

I pulled the top board and tested a few diodes that are in the 2 meter 
front end.  They seem fine.

The RF amplifier in the front end is a dual gate MOSFET, BB304CDW  (spec 
sheet: http://tinyurl.com/cx8hezz).  I don't know how to test this _in 
situ_, so I think the next step is to simply replace it.

Mouser doesn't have these in stock and they have a message, "End of 
Life: Scheduled for obsolescence and will be discontinued by the 
manufacturer."

So my questions are:

1.  Has anyone had a similar issue of an FT-857/817/897 going deaf on 2 
meters only?  Are there other things I should consider?

2.  Does anyone know of a good source for the BB304CDW?

3.  Does Yaesu sell components like this?   And if so, how long should I 
expect it to take to get the part from them?

Thanks in advance for suggestions.

Darryl, WW7D

07APR2013

Hello Darryl, et al:

I have actually gotten parts from Yaesu, particularly things like microphones.

You might call their technical people and speak with a 'live' person. This MIGHT 
help.

Seeing that the FT857D is still sold as new by AES/HRO/similar, it shoul;d seem 
that Yaesu would still support it.

I am forwarding this thread to the W6YX  & WSWSS reflectors.

bt73Pete, N6ZE in DM04ne today

-----Original Message-----
From: Darryl J. Holman <djholman at u.washington.edu
During last Monday's VHF sprint, it became apparent that my FT-857D went 
somewhat deaf on 2 meters SSB and CW.   Subsequent testing (using 
calibrated equipment) shows that it receives fine on all bands except 2 
meters.