Don: I just looked at the schematic. I do remember checking the voltage at R98 now that I look at it. I do recall getting over 7 volts in and somewhere around 5.8 give or take at the drain of Q24.
I never thought to look at U10 or associated circuitry. I will do that as soon as I get home. Thanks, Anthony n3kcb ------ Original Message ------ Received: Tue, 30 May 2017 10:14:48 AM EDT From: Don Wilhelm <[email protected]> To: Anthony Clare <[email protected]>, [email protected] Subject: Re: [Elecraft] K2 BFO issues Anthony, If you do not find more than 7 volts at the end of R98 that is furthest away from Q24, then look at the U10A/Q8 circuit on the Control Board. Check the associated components and their soldering. That is more likely to be the problem than the active devices. 73, Don W3FPR On 5/30/2017 9:28 AM, Anthony Clare wrote: > Hello: > > I am not at home to try, so I will have to check R98 later. I remember fitting > the encoder and it was definitely a tight fit. I used a dremel sanding drum to > almost completely flatten the pins in the affected area on the encoder board > and control board. Then I reflowed all the connections that I flattened and > placed fiberglass tape over the encoder board. Once I did this, I could look > between the boards and see no physical contact. > > I will separate the control and front panel boards and see what happens when I > get home. > > Thanks, > Anthony > n3kcb > > ------ Original Message ------ > Received: Tue, 30 May 2017 08:51:03 AM EDT > From: Don Wilhelm <[email protected]> > To: Anthony Clare <[email protected]>, [email protected] > Subject: Re: [Elecraft] K2 BFO issues > > Anthony, > > When you put the K2 into CAL FCTR mode, what is the voltage at the ends > of R98 (on the bottom of the board). I am interested only in the > highest voltage. > > With the new K2s (those using the new encoder board), many strange > problems are caused by contact of the encoder board with the Control Board. > You must flush trim the leads on the encoder board - and I mean almost > right down to the board level. > Also you must flush trim the back of the Control Board in the area that > could come in contact with the encoder board. > Make sure the rubber bumper pads are in place at the top corners of the > Front Panel Board. > > As a test, remove the 2 screws that secure the Control Board to the > Front Panel and tilt the top of the Control Board to the rear. If > things then behave normally, you can be certain that contact between the > encoder board and the Control Board is causing the problem. > > 73, > Don W3FPR > > On 5/30/2017 8:07 AM, Anthony Clare wrote: >> Hello: >> >> Looks like I am not the only one to have this problem. Just finished > assembly >> phase 2(?) on the K2. It was during the BFO tests that I realized there was >> not enough signal at the test point for the internal counter. I checked for >> poor solder, improper varactor diode install, verified that L33 was intact > and >> not being shorted by the 5 meg resistor, etc. I ran one crystal at a time, > but >> neither one would provide the proper signal level alone. I even checked L33 > on >> the inductance meter and it came out to about 39uH, which seems about right. > I >> assume the inductance meter has some error. The resistor measures out to > about >> 5 meg. >> > > ______________________________________________________________ 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]
