Hello,
Over the weekend while operating mobile in the PA QSO Party, my trusty old
FT757GXII suddenly froze, with the VFO at 14.033.9. Turning the VFO knob
wouldn't change the readout and the bandswitch wouldn't work. (Strangely,
the mode switch did work.) This condition continued for a few minutes and
then everything returned to normal. I had been using the rig for about six
hours at that point, using it quite heavily - lots of CQing with a memory
keyer, etc. A few minutes after I resumed operation, I started smelling
that old burning pcb smell. I then realized that the fan had not been
sounding normal all weekend, and I figured the rig was overheating. I
opened the door (I was parked) and gave the rig a rest. Fortunately it was
a pretty chilly day. I had been operating most of the day parked with the
engine off, and I wondered if perhaps the rig was getting enough voltage.
(I use two batteries in parallel and have never had power problems, but
normally I drive more, so it is possible that the voltage was a little
low.) After the rig cooled down for a few mintues, I tried it again with
the car engine on, and the rig performed well for the final three hours of
the contest with no smoke or smell.
I only use this rig three times per year in mobile contests, so I'm not as
familiar with it as I would be if I used it every week, but thinking back I
believe when the fan is operating normally it makes quite a racket. It was
not making such a racket this weekend, mainly pretty anemic moans if my
memory serves me correctly.
So, my question: is anyone familiar with this rig's fan? If I am right
that it is fairly noisy when operating normally, it is clear that my fan is
not working right and maybe not working at all. Is there a cheap and easy
fix for this problem? Tonight I took the top off and then removed the thin
steel sheet that covers the fan, and removed the fan. It appears to be
okay and the black plastic blade spins nicely on the shaft. Do I dare put
a drop of oil on the motor shaft? Of course, it is possible that the fan
is fine and that the thermal sensor is the problem. Is there any easy way
to bypass this and make the fan run all the time? Is there any reason that
this would be a bad idea?
I was planning to use this rig in the Illinois QSO party this coming
weekend, which will give it an 8 hour heavy duty workout. So there isn't
any time to purchase parts (except for Radio Shack or similar).
Any ideas/advice would be very much appreciated.
73,
Hal W1NN
|