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Expo 100 kit in a 142?
- Thread starter RugRat235
- Start date
it not to diffacult but you will need a frequency counter
cobra 142
Model B
EXPO 100
Instructions
1. Remove the covers from the unit and remove the 11.1125 crystal next to PLL chip MB8719.
2.Plug the removed crystal into the expander board and mount the expander by drilling a hole in the cabinet as close to the crystal socket as possible.
3.Solder the wires from the expander board to the crystal socket keeping the wire as short as possible.
4.Place the provided label to the side of the switch and position the knob to correspond.
Slider
1.Follow the wires from the two outside terminals of the clarifier control and cut them at the board.
2.Solder the right terminal of the clarifier control to circuit board ground. Solder the left side to the (+) side of capacitor C66 as shown in diagram B.
3.Cut diode D36 just in front of the PLL chip.
4.Unsolder the stripped end of the varactor diode next to the crystal socket, and solder the provided expander choke in series.
5.Cut resistor R187 on the right front side of the circuit board.
6.If additional slider range is desired, a 10uh choke can be substituted for the one in the kit.
Alignment
1.Turn the unit on, and place the expander switch in the normal position, the mode switch to AM, and the clarifier fully clockwise. Using a frequency counter while transmitting, adjust the trimmer capacitor next to the crystal socket to read +1 KHz above center frequency.
2.The power can be increased by adjusting the controls listed on the installation diagram.
Summary
The unit will now extend far above and below its normal operating range, as well as slide and track with the clarifier control. A slight adjustment of the VCO may be necessary if the unit drops out before reaching its maximum channels. This coil is usually filled with wax and should only be adjusted slightly for oscillation range desired.
thanks cb tricks
cobra 142
Model B
EXPO 100
Instructions
1. Remove the covers from the unit and remove the 11.1125 crystal next to PLL chip MB8719.
2.Plug the removed crystal into the expander board and mount the expander by drilling a hole in the cabinet as close to the crystal socket as possible.
3.Solder the wires from the expander board to the crystal socket keeping the wire as short as possible.
4.Place the provided label to the side of the switch and position the knob to correspond.
Slider
1.Follow the wires from the two outside terminals of the clarifier control and cut them at the board.
2.Solder the right terminal of the clarifier control to circuit board ground. Solder the left side to the (+) side of capacitor C66 as shown in diagram B.
3.Cut diode D36 just in front of the PLL chip.
4.Unsolder the stripped end of the varactor diode next to the crystal socket, and solder the provided expander choke in series.
5.Cut resistor R187 on the right front side of the circuit board.
6.If additional slider range is desired, a 10uh choke can be substituted for the one in the kit.
Alignment
1.Turn the unit on, and place the expander switch in the normal position, the mode switch to AM, and the clarifier fully clockwise. Using a frequency counter while transmitting, adjust the trimmer capacitor next to the crystal socket to read +1 KHz above center frequency.
2.The power can be increased by adjusting the controls listed on the installation diagram.
Summary
The unit will now extend far above and below its normal operating range, as well as slide and track with the clarifier control. A slight adjustment of the VCO may be necessary if the unit drops out before reaching its maximum channels. This coil is usually filled with wax and should only be adjusted slightly for oscillation range desired.
thanks cb tricks
yes, because when in extened mode it doesnt land on a full channel you will ne to use the clairifier to get on channel
example
my pro 810e base, same radio.
i would hit the switch and go to 27.5000, i would need to swing the claifier to 27.5050 to be on channel.
if you plan on using sideband with this radio again i would advise you not to convert it.
example
my pro 810e base, same radio.
i would hit the switch and go to 27.5000, i would need to swing the claifier to 27.5050 to be on channel.
if you plan on using sideband with this radio again i would advise you not to convert it.
Getting the radio on-channel for AM only is easier.
Getting it on-channel for BOTH upper and lower sideband, AND for BOTH upper and lower channels is a lot trickier.
Rather than clutter up the forum with a double post, here's the advice I offered in the "CB Radios" section.
forum.worldwidedx.com/viewtopic.php?t=7503
The radio's frequency will not be as stable with the EXPO kit as it was before. On AM, nobody will notice.
73
Getting it on-channel for BOTH upper and lower sideband, AND for BOTH upper and lower channels is a lot trickier.
Rather than clutter up the forum with a double post, here's the advice I offered in the "CB Radios" section.
forum.worldwidedx.com/viewtopic.php?t=7503
The radio's frequency will not be as stable with the EXPO kit as it was before. On AM, nobody will notice.
73
Thanks nomadradio. if i get in trouble i at least have some backup here. i know i posted this twice but i myself never come here to the tech area because i don't have too much knowledge to share and thought maybe someone might see it in cb radios that would have some input. sorry everyone .
Hey nomad that link doesn't work any more thinking I have an expo issue 
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