ICOM 706 MKII (not g)

[mattoxh]

I evidently burned the transmit circuit out on my 706 after connecting a dynamic mic (Kenwood MC-80). Now it will not transmit or go into transmit mode. I checked the interior fuse it is OK. I should have added a DC Blocking Capacitor to the Mic before connecting and keying up. Anyone have an idea what happened and most of all can I fix it or should I send in for repair.
73
Heyward
KI4PJY

 

[BJ radionut]

Heyward: Did you alter the wiring of the KWD MC-80 mic? Icom and Kwd do not use the same pin layout for the mic connectors.
Just curious as to how you made your hookup...
All the Best
BJ

 

[mattoxh]

Icom 706 not Transmiting

That may be part of the problem. Here is the story. I was given 2 Kenwood MC-80 Desk Mics by my sister, they came from her husbands Ham Grandfather that recently passed away. I thought it would be nice to have a desk mic for my 706 that I used in my shack as a base station. I researched and researched to determine pin wiring, purchased a male mic plug wired to a modular 8 pin cat 5 plug and hooked it up to my radio, no transmit. I researched more and found another internet site which changed some pin placement, did that, no transmit. Got to a point that I decided that I would leave my radio as it was and use the hand mic which is actually a good performer. Reconnected the hand mic and guess what no transmit. I did further research and learned that the hand mic is electret and powered by the radio. The Kenwood id a dynamic Mic. Connecting the Kenwood to my Icom would require the addition of a DC Blocking Capacitor in the wiring of the Kenwood, which is evidently an easy fix. Long story short I shorted out a circuit when I connected the Kenwood to the Icom when I powered up the radio and pressed the PTT on the Kenwood. I would like to fix this myself but probably should send it to Icom.
Thank You for your reply
Heyward KI4PJY

 

[longhaireddwb]

I'd say if you plan on keeping this radio for a few years you might as well send it in. Get it fixed and tuned up with a good alignment. This way you get the benefit of a properly tuned radio with the repair and you might also ask them about the mic wiring. It can be done.
If you think your going to replace it in the near future you could try to fix it yourself. You just learned the hard way to never plug a mic into a radio until you Know it wired correctly! I believe the Icom and the Kenwood radios have a pin that has voltage on it and there not the same voltage or the same pin.

 

[mattoxh]

Icom 706 not Transmiting

I suppose you are right I should send back to Icom or an authorized service center. In regard to the voltage, there is 8 volts on pin 1 that I imagine I redirected back into the transmit circuit.

BTW I like the Flags.
Heyward

 

[BJ radionut]

Did you try it in CW? Maybe it's just the audio circuit...worth a try
GL
All the Best
BJ

 

[mattoxh]

Icom 706 not Transmiting

I have never used CW. Can you use voice in CW mode will try and let you know.
Thanks for the reply
Heyward

 

[mattoxh]

Well this morning I powered up the 706 rolled through the modes to CW keyed mic nothing. I rolled through the menu and behold it is now transmitting on all bands. Not sure why but it is. No explanations. I appreciate everyone responding. If you know what I did let me know.
73
Heyward KI4PJY SC