[ICOM] IC-756 Hand Mic Problem

[Gary P. Fiber]

The HM-36 should drive the IC-756 just fine. You might have to turn up 
the mic gain over the Heil setting but that would not be unusal. I an 
wondering if somehow the 8 volts DC is missing or better yet being 
loaded when you attach the stock hand mics onto

 the IC-756? Mic conector Pin 1 should have 8 volts DC on it. You can 
check it between Pin 1 and Pin 6 or chassis ground. Then I would open up 
the mic connector, again stab Pin 1 with the positive end of the 
voltmeter, common to chassis ground and see if the 8 volts remains or 
drops off.
I have seen resistors go into trouble that feed Pin 1 the 8 volts, but 
not likely in 2 radios. Heil did at one time utilize a blocking cap in 
series with the Pin 1 connection in his adapter cabling. That should not 
effect the HM-36 so long as they are not attached to the Heil adapter 
cabling.
Can't say I remember having much trouble with the caps in the HM-36 in 
the 11 years I workd at Icom.The mics may have been to new then to see 
this type of failure.

Gary K8IZ



kc7hkp at comcast.net wrote:
> Hi Guys. 
> When i try the stock hand mic with my Icom 756 ( Non-Pro), Model HM-36 . I do not get any power out like its not hearing well, I tried a 2nd hand Mic same thing, Then i hooked up a Heil HM-i desk mic and i get full power out. If i Yell into the hand mic i do see some needle movement.
> I am not sure why the hand mic's do not work, i even put the Mic Gain and Comp to Full and still nothing.
> What am i missing ?
> Thanks , George
>
> --
> KC7HKP 
> George Yazzolino 
> 14801 NE 20th Circle 
> Vancouver, Wa. 98684 
> Grid CN-85 
> kc7hkp at arrl.net
>
> -------------- Original message -------------- 
> From: "Ekki Plicht (DF4OR)" <ep at plicht.de> 
>
>   
>> On Saturday 19 May 2007 04:42, John Hagle wrote: 
>>     
>>> I have been successful in writing software to read the operating 
>>> frequency and mode, as well as to set the frequency and mode on my Icom 
>>> 735, Icom 275 and Icom R7000. Either individually or together. 
>>>
>>> When I try to combine both computer operations at the same time I seem 
>>> to be getting conflicts on the data bus. I watch the flow of characters 
>>> and see unpredictable results. 
>>>       
>> Hello John, 
>> as Dave already pointed out, you should wait for the response from the rig 
>> before issueing the next command. 
>>
>> An alternative for frequency and mode/filter would be to use the commands $00 
>> and $01. Those are the only commands which do not yield a reply from the rig, 
>> allowing for faster (but unconfirmed) updates of freq/mode/filter. All other 
>> CI-V commands will effect a reply from the rig. 
>>
>> Maybe my CI-V website is helpful for this: 
>> http://www.df4or.de/civ/ 
>>
>> 73, 
>> Ekki, DF4OR 
>> ---- 
>> Your Moderator: Dick Flanagan K7VC, icom-owner at mailman.qth.net 
>> Icom Users Net: Sundays, 1700Z, 14.316 MHz 
>> Icom FAQ: http://www.qsl.net/icom/ 
>>     
> ----
> Your Moderator: Dick Flanagan K7VC, icom-owner at mailman.qth.net
> Icom Users Net: Sundays, 1700Z, 14.316 MHz
> Icom FAQ: http://www.qsl.net/icom/
>
>
>
>