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HW24H.MOD
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1990-09-29
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The following instructions will give you a step-by-step procedure for
modifying the bandwidth of the receiver section of your Transceiver.
These changes will expand the VHF and UHF bands of the receiver as
shown below:
FROM TO
VHF: 144 - 147.995 130 - 169.995
UHF: 438 - 449.995 360 - 489.995
( ) Disconnect the power plug to the Transceiver
( ) Place a towel or piece of carpet on top of your work area
so you do not scratch the Transceiver during the following steps.
( ) Position the transceiver with it's top down on the work surface, and
the rear of the radio facing you (antenna leads towards you).
( ) Pull out each side of the wire mounting stand and remove it from the
Transceiver (if it has been installed)
( ) Remove the five (5) screws that hold the bottom plate.
( ) Lift the bottom plate and hold it in your left hand. Then use long-nose
pliers to carefully unplug speaker plug J102. Set the bottom plate aside.
┌────┐ ┌────┐
│ │ │ │
┌─┴────┴────────────────────────────┴────┴──┐
│ FRONT of RADIO │
├─────┬─┬──────────┬─┬──────────────────────┤ ┌──┬─╥──╥─┬───┐
├─┐ ═╧═╧══════════└─┘════════════════════┌─┤ │ │ ║ ║ │ │
├─┘ /^ ^\ /^ ┌─────────┐ └─┤ │ │ ║ ║ │ │
│ QD22 QD24 Short ├─────────┴─────┐ │ │ │ ║ ║ │ │
│ Pins ┌──┤ │ │ │ └──────┘ │
│ to └ ┤ │ │ │ │
│ Reset* │ │ │ └─────────────┘
│ ┌─┐ │ │ │
│ │ │ <-Speaker Plug │ │ * Inset - exploded
│ └─┘ J102 │ │ │ view of area indicated
│ └───────────────┘ │ for shorting pins
│ │
│ ┌──────────────────────────────┐ │
│ ┌┐ │ │ ┌┐ │
├──┴┴──┘ └─┴┴──┤
│ ║ ║ ║ ║ ║ ║ ║ ║ ║ │
│ ║ ║ ║ ║ ║ ║ ║ ║ ║ │
│ ║ ║ ║ ║ ║ ║ ║ ║ ║ │
│ │
│ REAR of RADIO │
└───────────────────────────────────────────┘
( ) Referring to the diagram above, to expand the 144 MHz band, cut the
exposed bare lead of diode QD22. Bend the leads apart a little bit
so they will not accidentally touch each other.
( ) Similarly, to expand the 450 MHz band, cut the lead of diode QD24.
( ) Reconnect the power plug and turn the Transceiver power on.
( ) Write down the contents of your memory locations (the next step is
going to CLEAR the memory).
( ) Refer to the inset drawing and the area indicated by the pointer for
"Short Pins to Reset"
( ) Reset the Transceiver by briefly shorting together the two terminals
with a 1/4" or smaller flat-blade screwdriver. NOTE: The current
display will immediately disappear and the display frequencies will
be reset to 146.000 and 446.000 respectively.
( ) Turn the Transceiver off and Disconnect Power.
( ) Hold the bottom plate in your left hand while you plug in the speaker
plug J102. Then reinstall the bottom plate with the five screws you
removed earlier. DO NOT overtighten the screws; this could strip the
threads.
( ) If you are using it, reinstall the wire mounting stand.
( ) You can now reprogram your memory locations.
This completes the Receiver Bandwidth Modifications for your Twin Bander
Mobile Transceiver/Repeater.