FT101ZD mods
                      ============

Switching the fan.
~~~~~~~~~~~~~~~~~~
If using the rig for receive only, the PA cooling fan runs unnecessarily.
It is possible to switch it with the heaters on/off switch in a crude manner:
Pick up 12v AC from the Accessory socket. Half-wave rectify it with a diode,
smooth it with a couple of hundred microfarad and use it to drive a small 12v
relay which switches the 100v AC to the fan.

12v for external purposes.
~~~~~~~~~~~~~~~~~~~~~~~~~~
Useful to drive outboard units. Pick up 12v DC from the AF board J503 pin 7.
Feed it to a spare pin on the mic. socket via a 100R series resistor to
provide current limit.

Improving second DBM.
~~~~~~~~~~~~~~~~~~~~~
AF board, D02 - D05 are 4 x 1S4007. Replace these with 4 x Motorola MBD702
diodes then adjust VR01 and TC02 for best carrier balance. It should be
possible to null the carrier almost completely. Diodes may be obtained via
the FT Owners' Club (Stateside).

First mixer overload.
~~~~~~~~~~~~~~~~~~~~~
Improve the dynamic range of the first mixer by modifying the T-pad
attenuator on the input as follows: RF board - change R8 (120R) to 36R. R9
(10R) to 27R. R10 (10R) to 27R. Reset overall gain on IF board using VR02
which is in the source lead of Q15.

Improved fine-tuning.
~~~~~~~~~~~~~~~~~~~~~
Shunt the clarifier control with 4K7 or 5K6 then recentre its action by
adjusting VR01. This reduces the control's range.

Improved PA cooling.
~~~~~~~~~~~~~~~~~~~~
Cover half of the top surface of the PA compartment. Cut a triangular-shaped
card and fit it over the top of the PA compartment so that the rear and inner
edges of the compartment are covered. This redirects the fan airflow so that
the PA valves are more effectively cooled.

G3TJP @ GB7SAM

(Downloaded from GB7SYP)