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MARS / CAP TX Mod for the Kenwood TH-K20A

AudioShockwav

Extraterrestrial
Staff member
Apr 6, 2005
9,421
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Nor Cal Sierra Nevada
((Caution: This modification requires soldering equipment ratedfor CMOS type circuits. It also requiresfamiliarity with sulface mount soldering techniques. Ifyou do not have the proper equipment or knowledge, do not attempt this modification yourself Seek qualifled assistance.))


KENWOOD TH-K20A – Full Extended TX Modification

This modification is provided "as is," and is subject to change without notice. The author makes no warranty of any kind with regard to this modification procedure. The author shall not be liable for any error or for incidental or consequential damage in connection with the furnishing, performance, or use of this modification procedure.

It is illegal to operate outside the limits of your class license or permits. Procedure:

Turn off the transceiver and remove the battery pack.

Remove the antenna, channel selector knob, and volume knob.

Remove the Side Jack Accessory Cover.

Remove the two screws from the bottom of the radio on the back side.

Carefully lift the front panel up from the chassis, starting at the bottom of the radio. Be careful not to damage the speaker wires as you’re opening the radio.

Locate and carefully remove both Diodes reference C & D from the TX/RX unit - (see Figure 1).

Assemble the transceiver.

Reset the radio.
Press and Hold the F Key While Turning the Radio On
Release the F Key
Use the Channel Knob to Select Full Reset (FL.RST)
Press F then Press F Key Again to Confirm Reset
Transmitter Operating Range: 136 ~ 173.995MHz


73
Jeff
 

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have new th-k20 fm trans removed diodes d an c done full reset but only can do 144 up 147 are there another diode in new ones that has to come out to open
 
have new th-k20 fm trans removed diodes d an c done full reset but only can do 144 up 147 are there another diode in new ones that has to come out to open

I have exactly the same problem.
After running unrestrained for 2 years, my TH-K20E radio clamped down to 144-147MHz.
My radio behaves like an M type radio
Does someone have an idea ?
Well done and huge thank you to the one who will give me the solution!
 

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