Check Q232, the APC circuit transistor, used for VHF operation.
Resolution outlined in Kenwood Service Bulletin no. 1056 (28 March 1994)
Problems with the Toshiba S-AV17 RF Power Modulehttp://www.repeater-builder.com/kenwood/s-av17/s-av17-repair.html
Do not wait too long, as Toshiba has supposedly discontinued the part.
RF Parts is suggesting the Icom SC part as suitable replacement.http://www.repeater-builder.com/kenwood/s-av17/s-av17.pdf
Check the Kenwood Service Bulletin, found here,Scroll down to Service Bulletin no. 1056 (28 March 1994)http://www.qsl.net/v/ve7lgp//kenwood...d%20TM-732.htm
23-04-2000 TM-732A/E APC circuit improvement
Author: Kenwood Communication, inc.
Service Bulletin no. 1056 (28 March 1994)Symptom
:Failure of APC circuit transistor Q232 can occasionally be attributed to the
gain dispersion charcteristic of the VHF Power Module.
Some of these devices allow normal transmit power output even with reduced "DB" terminal voltages.
If the units is then operated for extended transmit key down periods Q232 can overheat and fail.
Measure the transmit power output and the "DB" terminal voltage at a dial frequency of 145.02 MHz.
Add the 1 dB circuit if the transmitter power is 60 watt or greater and the "DB" terminal voltage is 10 Vdc or less.
After adding the attenuator, re-adjust the transmitter output power for 50 watt and check the "DB" voltage.
The "DB" voltage should now fall between 10 and 11 Vdc.
If it does not adjust the values for R98, R100, and R99 until this voltage range is obtained.
Qty Description New Part No. Circuit Description
* 820 ohm chip resistor RK73FB2A821J R98, R100
* 470 ohm chip resistor RK73FB2A471J R98, R100
* 270 ohm chip resistor RK73FB2A271J R98, R100
* 5.6 ohm chip resistor RK73FB2A5R6J R99
* 10 ohm chip resistor RK73FB2A100J R99
* 18 ohm chip resistor RK73FB2A108J R99
* Note: Quantities vary depending upon level of attenuation required to meet requirement of step 3.