[Heathkit] SB-100 TX audio gain question

[ed wirtz]

Sandy,

Make sure you are using a hi impedance microphone. The SB100 has a high 
Z input requirement. The newer Lo Z microphones will not work correctly 
with the tube type amplifiers in the SB100 without a matching 
transformer. Other that that, it could be a bad capacitor or out of 
tolerance resistor in the audio chain.

Good luck. These older radios seem to do this regularly it seems.

73,

Ed, KØBKA

On 12/27/2015 2:02 PM, Alexander N. Gerli wrote:
> Hi, Folks!
>
> My SB-100 is working fine, with one little exception: to have any TX audio
> out, I need to have the MIC/CW Level set virtually max. Checked the output
> waveform on my SB-610 scope, and it appears clean. The tubes in the mic
> audio chain are good, so I'm not certain what may be up. Seems as if the
> level should be optimal around 50% or a little greater, but not maxed out.
>
> Anyone have a suggestion where I might start looking?
>
> ​73,​
>
>
> ​Sandy AC1Y​
>
>
> Alexander N. Gerli, Sr.
> 548 Allred Mill Road
> Mount Airy, NC 27030-2202
>
> Scotsmen walk about 900 miles each year.
> A Scotsman drinks around 45 gallons of Whisky a year.
> Scotsmen get about 20 Miles Per Gallon.
> ______________________________________________________________
> Heathkit mailing list
> Home: http://mailman.qth.net/mailman/listinfo/heathkit
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Heathkit at mailman.qth.net
>
> List Administrator: Duane Fischer, W8DBF
> ** For Assistance: dfischer at usol.com **
>
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html