[Yaesu] FT-3000M Fan noise in Xmit

[Carol L Maher]

Hey guys,
I thought I would pass this along just incase any of you have one of
these
2 meter Jewels.  The FT-3000M 2 meter transceiver expensive (70w)
rig just a few years ago.  I bought one last year from AES on close out
and installed it in my car.  Although two meters is not my band of
choice, 
I can only assume that most of us have a couple of these around the shack
and one in the car.

After a using the mobile rig a while I decided I really liked this
transceiver
and the 70 watts gives it one heck of a punch, considering that it wasn't
too
long ago that one had to buy and external power amplifier to get this
kind 
of power out of their 2 meter set up in the car. 
In fact I thought I would simplify my life and try and buy
another similar rig along with the programming software and cable then
put it in
the ham shack.  There by having only to use the Lap Top PC to update the
frequencies between the two rigs.

I bought a second hand FT-3000M (Like new) off E-bay this past week.
Basically it appeared to be working well when I was testing it last
night for the first time.  Then a minor problem popped up.
Minor, but worth noting.   I was talking with my fried across town using
the rig
in the house using high power, when the two muffin fans mounted on the
rear heat
sink started up.  It was strange because the fans were inducing noise
into the
transmit side of things.  Nothing could be heard in the receiver and the
fans
could not even be heard in the shack.  My friend told me it sounds like I
had
a siren going off in the background as the fans came up to speed.
Listening in on a local receiver, I could also hear the fans, like he
said!
Sirens.

Like most hams, the first thing you do is pull off the cover!
(Hey it's out of warranty!)  With the rig sitting in my lap,
turned on and running at high power. Again the fans kicked on....
nothing could be heard on the other end or in my local receiver. All
I did was to remove the bottom cover.  Hummmm.  
Put the cover back on the FT-3000M and the noise came back.
Now while it appears that I've fixed the problem, I'm not 100% sure why.
But I can guess.  Looking at the bottom circuit board where all the
components
are mounted, I the bottom cover and slightly bent the cover outward just
a tiny bit, not even enough so that it can be seen. 
Then looking at the circuit board and majority of the guts to 
this rig, we see four small boards  that sit in a vertical position.
The boards are just covered with (SMD) surface mount components,
transistors, capacitors, resistors and so on.  My conclusion is that one
of the boards must hold the microphone pre-amp and what ever induction
or vibration that was felt through the case covering must have just been
enough to modulate the rig when the fans kicked in and started
blowing.  I decided to take three strips of electrical tape and cover the

inside of the transceiver cover, just one piece each on the inside cover
above
each circuit board.  Not too much tape, just a small amount to avoid a
mess
later when the tape gets old.  I put the cover back on the FT-3000M and 
NO MORE PROBLEM, fixed.

One other small thing I noticed.  The power output on my Bird Watt meter
appeared to be a bit low. The rig has four power settings.  Without
getting
into all the details.  I basically did a  reset of the transceiver as per
the
owners manual and now all power setting are back up to normal.
I have no idea what exactly was reset,  but the power comes up
to spec now.

I hope this helps someone down the line, when you pick up a
second hand rig you never really know what your going to run into.
The FT-3000M purchased new from AES last year never does not appear
to have any signs of the fan noise problem.
Best Regards to the group.
Carol L. Maher
W4CLM