[Elecraft] Set up of Heil ProSet K2 Headset assembly

[Don Wilhelm]

Ray,

Voltages on those other pins are as expected - a quick perusal of the 
front panel schematic will tell you why.

It may be that the computer mic expects the bias voltage on the ring 
instead of the tip, some do while others do not.  If the computer 
soundcard puts bias on the ring, but not the tip, the Proset would not 
work in the computer.

If you have an oscilloscope, you can see if there is any audio signal at 
the input to the KSB2 board.  The level will be low, but you should be 
able to see it on a 'scope with a sensitive setting.

I don't know what was involved in removing that small adapter board that 
you found in your K2, is there any possibility that a trace had been cut 
between the microphone input and the corresponding pin on the microphone 
configuration header to insert the Yaesu adapter?  It would be easy to 
check that with an ohmmeter.  When un-doing someone else's mods, it 
often takes a lot of sleuthing unless the changes have been well documented.

We are down to pure guesses at this point, you have already checked out 
the usual problem areas.

73,
Don W3FPR

On 11/5/2011 1:34 PM, Ray Spreadbury wrote:
> Hi Don
>
> I can confirm the following points -It is an Elecraft ProSet which I bought
> direct from Elecraft, all pins on the configuration header have a jumper
> straight across, the 5.6K resister is soldered across pins 1&  6.
>
> With the microphone not connected, 5.08 volts is present at Pin 1&  6, (and
> as it happens, also 5.66v on pin2, and 4.99v on pins 3,4&  5)&  pins 7&  8
> have zero ohms to earth.
>
> The ProSet microphone did not work with my computer soundcard but my
> computer microphone (which works OK with the soundcard) plugged into the
> adaptor, did not produce audio in the K2 either!
>
> The only thing I can think of now is to try&  borrow an Elecraft ProSet from
> a nearby friend&  see if that works in my K2.
>
> Any other ideas please?
> 73, Ray G3XLG
>
> -----Original Message-----
> From: Don Wilhelm [mailto:w3fpr at embarqmail.com]
> Sent: 05 November 2011 12:30
> To: Ray Spreadbury
> Cc: elecraft at mailman.qth.net
> Subject: Re: [Elecraft] Set up of Heil ProSet K2 Headset assembly
>
> Ray,
>
> It sounds like you did everything right.  Sorry to hear of your
> disappointments.
> Do you have a computer soundcard that you know works with a computer
> microphone?
> If so, plug the Proset K2/3 mic into that soundcard - it should work.
> To check the adapter, plug a computer mic into the Proset adapter - it
> should produce audio in the K2.
>
> Just to double-check your installation - all pins on the microphone
> configuration header should have a jumper straight across, and the 5.6k
> resistor should connect between mic jack pins 1 and 6.
> With the microphone not connected, check for the presence of 5 volts at
> pin 1 of the mic jack.  Also check for zero ohms to ground at pins 7 and 8.
>
> 73,
> Don W3FPR
>
> On 11/5/2011 7:33 AM, Ray Spreadbury wrote:
>> I then re-fitted the boards and reset SSBA = 1, SSBC =2, POWER = 5 watts&
>> tested the rig with both PTT&   VOX. I found:-
>> Receiving, everything working OK with either the LS or the ProSet
> headphones
>> CW everything working OK
>> PTT switch appears to work OK, VOX apparently not working&   got no audio
>> output from the microphone with either VOX or the PTT. I.e. there was no
>> movement of the K2's power display.
>>
>> Having re-checked the wiring on the mic. socket&   the 5.6k resistor, I
>> suspect the Heil condenser mic is not working - how can I check it or are
>> there other things I should look at?
>>
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