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]
