Don, C2 is already .01uF. Are you suggesting I try a .1uF?
Jeremy > On Oct 31, 2017, at 11:50 PM, Don Wilhelm <[email protected]> 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 <[email protected]> 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. >>>> >>>> >>>> >> > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
