"John" wrote in message
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"John" wrote in message
...
I have just got my TR751 working. (Kenwood 2m multimode transceiver)

Does anyone have details of the APC adjustment procedure? Also details
of
which pot controls power output in Hi power position. I am getting
nearly
40 Watts out on FM in to 50 ohms whereas the spec says 25 Watts. I want
to
turn power out down so as not to stress the output brick.

Thanks


I'm not sure what you mean by "APC adjustment procedure".
The complete transmitter adjustment covers two and a half pages and
requires a lot of test equipment. RF voltmeter, frequency counter,
power meter, DC voltmeter, linear detector, oscilloscope, spectrum
analyzer, and AF voltmeter to name most of them.

The power adjustment is the easy part.
Place the radio in front of you with the controls toward you.
Remove the top cover.
In the right rear you will find VR4, VR3, and VR7 close together
on the composite unit (TX) board. They form a triangle.
VR3 is the low power adjust
VR4 is the high power adjust
VR7 is the CW break in delay

Low power is supposed to be adjusted for 5 watts
High power is supposed to be adjusted for 27 watts

Power should be adjusted with the radio in CW mode.
A VHF capable 50 ohm dummy load must be used for the adjustment.

Be careful - there are three VR3 and two VR4 pots in the radio.

John


Thanks a lot for the info John. Have now adjusted power o/p as you suggest.
Am I right in thinking that you have a TR-751 ? On SSB mode my 751
receiver background noise is very quiet although the RX is quite sensitive.
What is the background noise on SSB mode like on your 751 ?

Does the service manual run to many pages ? Do you have a scanned copy by
any chance ? I do have access to all the necessary test equipment in your
list.

John G3UGY