TS140S From: KC4JCZ@WA4ONG To: KJ6FY@KJ6FY Hello from Richmond, Va. I noted your message about looking for a mod. Unfortunately I don't have that mod. I do have, however, the mod for the Kenwood TS-140S HF all band radio if you want it. Snipping diodes D29 and D31 not only will permit all-band, all-mode transmit, but it will also unlock the 40 and 60 watt limit for FM and AM power max respectively. I am, however looking for a mods for the Kenwood 2m mobile rig (221 I think) that will allow it to TX/RX up to 170 MHz or higher. I am already aware of the mod for that rig where you snip the wire looking around the display to mod for MARS/CAP (up to 151 MHz). Also am interested in a mod to unlock the Yaesu FT-212RH 45 watt mobile rig for TX/RX up to 170 megs or higher. A friend would rather buy one of these rigs than buy a mobile 2m and a marine radio. (he is aware of 25 watt ceiling for marine). Many thanks..will keep you informed of any future mods I hear of. (P.S. cut diode D81 on Kenwood 440 HF rig for all-band MARS/CAP. almost forgot!). 73...de Bill KC4JCZ @ WA4ONG (aka RICBBS) -=-=-=- TS140/680 Service Tip After replacing finals and/or drivers in the TS140/680 check that all filter relays are operating correctly. Failure of a band's relays to pick will cause the finals to run into an open circuit and possibly (probably?) damage them. Check the following points for approximately 12 volts. These diodes are on the filter board next to the final unit. Band Diode Band Diode 1.8 D1 24.0 D6 3.5 D2 28.0 D6 7.0 D3 28.5 D6 10.0 D4 29.0 D6 14.0 D4 29.5 D6 18.0 D5 50.0 - 54.0 D7 TS680 only 21.0 D5 If the problem is in the 1 of 10 decoder chip IC2 on the signal board (74LS145) unlock problems may also occur. Fred Burton .. @ VE3HPL -=-=-=- Subject: TS-140S Sidetone Mod TS-140S Sidetone Mod I recently purchased a Kenwood TS-140S after using it on CW for about a week, I decided to try it on SSB and AM. When I pushed the AM and SSB mode switches, I heard a constant audio tone emanating from the rig. As I diconnected the rig, preparing to return it to the factory, the tone stopped. Investigating the circuit diagram, I noted that the CW key has to be unplugged to kill the sidetone. There is no mention of this in the Instruction Manual. Perhaps my experience may save others the frustration I encountered. Also, amateurs should pay attention to the proper use of receiver noise blankers. I know of instances where operators were handing out reports of distorted signals to outhers, only to discover that it was their improper use of the receiver noise blanker that was producing the distortion... Ed, W6XM -=-=-=- SB-928 TS-140S Intermittent loss of TX power 4-11-88 In some TS-140S transceivers, the drive transistor, Q2, is not firmly mounted to the heatsink. This can cause a loss of transmit power after the unit warms up. The following modification will correct this condition. 1. Disconnect the TS-140S from the antenna and power supply. 2. Remove the top and bottom covers. Open the sub-chassis. Refer to the instruction manual for step by step instructions. 3. Remove the shield plate from the sub-chassis (12 screws) to expose the filter an final units. Do not loose the 2 springs that are secured by the right side screws. 4. Resolder Q2 so that the transistor makes firm contact with the heat sink on the Final unit. Tighten the transistor's mounting screw. 5. Assemble the transceiver by reversing steps 1 through 3. This modification may be performed under warranty. Time required for this change is 1/2 hour or less. (c) 121589TKC PORTED AND REALIGNED FROM PC TO AMIGA FORMAT BY BOB G0LBQ - N6XDI.