Subject: IC-746 Modification From: "Schmitz, John" Date: Fri, 13 Aug 1999 07:14:49 -0400 IC-746 Mod. Remove the twelve screws holding on the bottom cover. With the Radio laying flat on it's top remove the bottom cover. Turn the radio so that the front panel is to your left and the antenna connectors are to your right. Locate the IC labeled "ICOM HD6433042SF". About 3/4 of an inch to the right is a vertical row of diodes. The left hand column of diodes has 7 diodes (14 possible spaces). The right hand row is full with 14 diodes. Remove the diode in the 6th space from the top in the left hand column. DO NOT remove anything from the right hand column. This should get you TX from about 100KHZ to 60MHZ and 118MHZ to 176MMZ. Do this totally at your own risk. Never, ever transmit out of the ham bands or your privileges.. John Schmitz NS8E ------------------- Editor, I think that there is a new configuration for the IC-746 diodes which open up certain bands. I would like the opportunity to mention that in the mod that I sent in before. I do not have the answer to it, so I would like to re-write the mod that you currently have. I've attached below what should be a better mod page for the IC-746 John NS8E --------------------------------------------------------------------- IC-746 Mod. This is the mod for an IC-746 with the diodes in the 1, 2, 4, 6, 9 and 14 position and the description below explains this. ! IMPORTANT ! There seems to be new version of the diode pattern out there with diodes in the 1, 3, 4, 6, 7, 10, 11, and 14 position and the mod DOES NOT work for this pattern. If you find this pattern after reading the mod below, DO NOT try it. It DOES NOT work. If I find the mod for that pattern I'll try to get it posted here also. Remove the twelve screws holding on the bottom cover. With the Radio laying flat on it's top remove the bottom cover. Turn the radio so that the front panel is to your left and the antenna connectors are to your right. Locate the IC labeled "ICOM HD6433042SF". About 3/4 of an inch to the right is a vertical row of diodes. The left hand column of diodes has 7 diodes (14 possible spaces). The right hand row is full with 14 diodes. Remove the diode in the 6th SPACE from the top in the left hand column. DO NOT remove anything from the right hand column. This should get you TX from about 100KHZ to 60MHZ and 118MHZ to 176MHZ. Do this totally at your own risk. Never, ever transmit out of the ham bands or your privileges.. John Schmitz NS8E --------------------------------------------- At a Ham Fest last year I purchased a Kenwood MC-60 microphone with the intention of using it with my ICOM IC-746 transceiver. Figuring out the microphone and PTT connections was pretty straight forward. However making the Up and Down switch work with my ICOM was not that straight forward. Kenwood uses separate lines for the Up and Down functions while ICOM uses one. Having other things to do at the time, I simply hooked up the microphone and the PTT switch and used it without the Up/Down function. Now I'm sorry I took so long to get back to the project. After doing some investigation I figured out (using the original ICOM microphone) that the Up function on the ICOM was achieved by grounding pin 3 on the ICOM microphone connector. The Down function was done by grounding pin 3 through a 470 ohm resistor. The solution was simple. Add a 470 ohm resistor across pins 3 and 4 on the back of the connector in the base of the MC-60 and connect pin 4 of the microphone to pin 3 on the ICOM. (See figure) David M. Hitchner - hitchner@home.com Baton Rouge, LA KD5EIS - kd5eis@arrl.net