MODS FOR THE ICOM IC211E
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1. LATCHING FAST-TUNE
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The IC211E normally tunes in 100Hz steps, but by holding the Fast-Tune button
in, it tunes in 5kHz steps. This is a two-handed operation, and not easy to
do when you are also trying to hold a beer mug, cigarette, etc.
My solution is to make the Fast-Tune button into a push-on, push-off system.
This was done using a CMOS flip-flop of the 4013 type, with the NOT-Q output
wired to the D input. The wire to the Fast-Tune button is disconnected, and
re-connected to the Q output. The button is then connected to the C (clock)
input of the 4013. Don't forget to connect all unused inputs somewhere
sensible, remembering that the 4013 is a DUAL flip-flop.

An R-C network on the RESET pin will help to bring up the 4013 in a defined
state when you switch the power on. The circuit can be constructed on a piece
of Veroboard about an inch square, and hung off one of the spare threaded
holes along the side panel of the rig. After all, its only one chip, one
resistor and one capacitor!

Further to this, I decided that some sort of Fast-Tune indicator would be
nice, along the same lines as the Dial Lock lamp. I didn't want to drill
extra holes in the front panel, so I used the last decimal point of the
display. This means that when I'm in Fast-Tune mode, I have 3 decimal points
lit instead of the normal 2. I drove the dec. pt. from the NOT-Q output via a
transistor buffer, using a BC108 and a resistor in series with the base. It
is just possible to attach a wire to the back of the display board without
removing the front panel, and Bob's your uncle! To incorporate this extra
mod, the Veroboard needs to be slightly increased in size to accomodate the
transistor and resistor, but I don't really see this as being a problem.

2. BATTERY BACK-UP
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Being a fairly old rig, the IC211E has only 2 memories, these being the VFO
frequencies when the rig is switched off. It contains a low-power PSU, in
addition to the main PSU, for memory retention.
Naturally, the memories are lost in the event of a power cut or someone
tripping over the mains lead. This means that you have to re-program any
repeater offset, and both VFOs start up on 144.0000. This is not useful,
especially if the rig is being used for unattended Packet operation.
It is the work of a moment to install a set of Ni-Cad button cells, charged
via a resistor and diode from the auxiliary supply at the C/100 rate. The
current-limiting resistor to achieve C/100 will depend on the capacity of the
button cells you choose.
The diode is used to ensure that when the power is off, the Ni-Cads are not
attempting to power the PSU! There is a convenient chassis rail near the aux
power supply to which the Ni-Cads can be Tie-Wrapped, and there is bags of
space in this area.
The whole lot can be wired via the Memory On/Off switch on the back panel, so
that if you go away for a long time, you can switch EVERYTHING off. This will
avoid the Ni-Cads going into a deep-discharge state.

                              *** WARNING ***

Please don't attempt these mods unless you know what you are doing.
There are mains voltages inside the IC211E, so watch how you go.

73 Chris G4OUG @ GB7SAM

(Downloaded from GB7SYP)