[Elecraft] K2 - Strange Problem ?

[Stewart Baker]

On Tue, 30 Nov 2004 08:01:25 -0800, Vic Rosenthal wrote:
> Stewart Baker wrote:
>> The amplifier only draws about 1mA, however because of noise on the 5A line,
>> mainly from the LED bar graph I have had to heavily decouple the pre-amp
>> supply
>> to stop the noise from being superimposed on my speech.
>> What I think is happening is that this decoupling is affecting the rise
>> time of
>> the 5A line which is used for the MCU reset amongst other things.
> Why don't you do this (must be viewed in fixed width font):
> 5V -------\\\\\\\----|----> to preamp
> large R     |
> ---
> ---  cap for decoupling
> |
> ---
> ///
> You will get better decoupling and isolate the capacitor from the 5V rail.

Thanks Vic,

That's what I was doing, however, because anything capacitive slows the rise of 
the 5A rail, and hence the correct MCU initialisation, I was chasing my tail.

A better solution has presented itself.

73
Stewart G3RXQ