[Elecraft] 2T Gen problem

[Jeremy Jones]

Don,

C2 is already .01uF.  Are you suggesting I try a .1uF?

Jeremy

> On Oct 31, 2017, at 11:50 PM, Don Wilhelm <donwilh at embarqmail.com> wrote:
> 
> Jeremy,
> 
> Those voltages seem to be OK.
> 
> I have obtained information from Elecraft support that C2 may be the problem.
> The capacitor may be too low in value.
> Replace C2 with a .01uF capacitor and see if that fixes the 1900kHz oscillator.
> 
> 73,
> Don W3FPR
> 
> On 10/31/2017 9:14 PM, Jeremy Jones wrote:
>> Don,
>> 
>> Q2 Gate = 5.20v
>> Q2 Drain = 4.66v
>> 
>> Jeremy
>> 
>>> On Oct 31, 2017, at 6:37 PM, Don Wilhelm <donwilh at embarqmail.com> wrote:
>>> 
>>> Jeremy,
>>> 
>>> What is the voltage at the gate of Q2?  And what is the voltage at the drain?
>>> Those two points should control the level of the 1900Hz tone.
>>> 
>>> Likely possibility is that Q2 was damaged by static when installed.
>>> 
>>> You should have the JP2 jumper set for the "T" position.
>>> 
>>> 73,
>>> Don W3FPR
>>> 
>>> On 10/31/2017 6:01 PM, Jeremy Jones wrote:
>>>> Hi Don,
>>>> 
>>>> I have the 700Hz tone, but not the 1900Hz.  Here is the quote from the original post.  I measured similar voltages.  I’ve also included your response to him.  It seems like a pretty simple device, and I’ve double checked the components and soldering.  My 12 year old daughter did most of the soldering, so the only thing I can think of is her leaving the heat on too long and damaging a component, but there are no burn marks on the circuit board.
>>>> 
>>>> The 700 Hz generator works and produces a max 150 mVolt peak signal, but the
>>>> 1.900 Hz generator does not work. I noticed that Base of 2N3904-Q1 (1.900
>>>> Hz) shows 0 V, while Base of 2N3904-Q3 (700 Hz) shows 2,1 mV. With a 8.9
>>>> Volts Vcc, Collector Q1 shows 8,1 Volts while Collector Q3 shows 6.7 Volts.
>>>> Drains Q2 and Q4 (2N7000) show both 4.4 V (= Vcc/2). The voltages of pins
>>>> 1,2,3,5,6,7 of U1 (LMC6482) are all 4.4 Volts. Replacing Q1 with an
>>>> available spare didn't help and didn't change the voltages.
>>>> 
>>>> 
>>>> 
>> 
>