FT 1000MP Cooling Fan Mod

Problem: 15 hours continues running per day for the FT1000MP makes him a
lttle bit hot under his case even if there is only RX in use. The
cooling-fan does not operate on RX. Only if the PA-Stage is used the sensor
switch the fan on with maximum speed.

Solution: If the fan are running continues with reduced speed (and reduced
noise) there will be no more problems with heat in the rig. A simple way to
do this shows the circuit-diagram. Lets start with the modifikation:

Disconnect the power from the FT1000.

Open the upper case. Locate the REG-UNIT on the left side of the rig.

Loosen the two screws from the cooling-fan at the left and right side of the
PA-Unit.

Plug out the wire from the fan at the REG-Unit.

Connect Power to the TF1000. Switch the rig on.

Measure at the now open socket on the REG-Unit the two pins. One of them has
13 Volt against ground. Remember this side of the socket and plug!

Disconnect power from the FT1000.

Put the fan-plug in the socket.

Carfully solder a cable at the pin of the plug that has !! N O !! 13Volt to
ground! This one is the pin that swiched to ground when sensor in the
PA-Unit is getting warm.
To this wire solder a Diode 1N4001 with anode. To the Kathode solder a
Resistor of 220 Ohms 2 Watts. The other end of the resistor connect to
ground.

Paralell to the resistor put a electrolyte-condensor with 2200 Mycrofarads
and min. 16V Voltage with the positve side towards the diode and the
negative side to ground. Ready for takeoff...

How does this modifikation works?

Well after switching on the FT1000 the 2200 Mycrofarad C is empty and a
loading-current flow from the 13V source via the fan-Motor, via the diode
into the capacitor. This current is strong enough to start the motor
running. When the Capacitor is charged only the 220 Ohm Resistor limits the
current through the fan-motor. His speed and noise is reduced. Maybe you
must change the value of this resistor due to the "mecanical wellness" of
the fan motor and the noise you can akcept for continues running.
By the way, the diode make sence for when the sensor in the PA-Unit switch
to ground. This diode protects the switching-transistor from the
discharge-current of the electrolytecondensor.

Put all things together, specially take care of the fan by remounting it to
the PA-Unit (easy running and no cable around)!

Here in my rig it works well. Cooling fan is runnig at low speed and low
noise continuesly. On TX sometimes after long TX-time the fan swiched up to
his maximum speed and falls down to slow operation after RX is in use.