Hi Don, You nailed it. No output from the 15 MHz crystal. The other three bands are showing good output. I checked the relays K1 and K2 to verify each has pins 3 to 4 conductivity when on 40 meters (set radio to 40 meters, power down, and remove filter board since relays are latching. One side of crystal checks good to ground and the other side checks good to P1 pin 4.
Ordered new 15 MHz crystal from Elecraft. Thanks for the advice. Once I got the RF volt meter it took a few minutes to find the problem. 73 and thanks again! Dave wo2x -----Original Message----- From: Don Wilhelm <donw...@embarqmail.com> Sent: Wednesday, May 20, 2020 2:37 PM To: rocke...@gmail.com; elecraft@mailman.qth.net Subject: Re: [Elecraft] K1-4 low power and poor receive on 40 meters There is the possibility that the 40 meter crystal has low activity. Check the RF voltage at pin 4 of P1 on the band board. You should read 70mV or more with an RF Probe or 200mV+ peak to peak if using a 'scope with a 10X probe. A good working K1 will develop at least 5 watts. Make up an RF probe if you don't have one. It does not have to be fancy, just stick the component leads through a piece of cardboard and solder the leads together. You need a 1N34 diode (not a silicon diode) Elecraft does have a kit. 73, Don W3FPR On 5/20/2020 1:35 PM, rocke...@gmail.com wrote: > Hi Don > > I have done that using the Marconi for RX, then touching up for TX. I > understand 40 is a combo of 30 & 40 settings. After carefully retuning (done > it several times) the best I can get on 40 is about 60 to 75 mW. 30 makes > better than 2 watts. The menu for power out is set to 2.0 on 40. Receive > sensitivity is 10 to 15 dB down from 30 meter receive. > > I read that the windings on T3 and T4 are critical. I have counted the > turns and verified which side #1,2,3 and 4 are coming off the core. > Both T3 and T4 appear to be fine. There is enough wire left over in > the box the radio was in so I can rewind T3 or T4. From what I see on > the schematic T4 would most likely be the suspect (if it is the > transformer.) > > I am going to borrow an RF Power meter with probe and check 30 vs 40 meter > readings on the Premix in & out and the RF filter in & out. That will greatly > help pinpoint the issue. > > 73 > Dave wo2x > > > -----Original Message----- > From: Don Wilhelm <donw...@embarqmail.com> > Sent: Wednesday, May 20, 2020 11:39 AM > To: rocke...@gmail.com; elecraft@mailman.qth.net > Subject: Re: [Elecraft] K1-4 low power and poor receive on 40 meters > > Dave, > > Refer to the K1FL4 instructions and re-tune the trimmers on the filter board. > They MUST be done in the proper band sequence - 30 meters before 40m, 15m > before 20m. The PreMixer portion is usually the most critical for power > output. > > 73, > Don W3FPR > > On 5/20/2020 11:20 AM, rocke...@gmail.com wrote: >> Hi All, >> >> >> >> I am going to sell a K1-4 (4 band 40, 30, 20, 15) for the estate of >> my Elmer. In testing the radio I found 40 meters is about 15dB less >> sensitivity than 30 and power out about 75 mW. I have double checked >> the values of components on the filter board to ensure they are >> correct and installed correctly. I also checked T3 and T4 which can >> cause issues on 40. T3 has 23 turns on the secondary with three turns >> on the primary. T4 has 24 turns on secondary and two turns on primary. >> Another symptom is the CH trimmer cap seems to be at one end of tuning range >> (not seeing double peak). >> >> >> >> Note - the radio does not have the ATU option and 30 meters is set >> for >> 10.1 MHz and not 10.0 (double checked crystals). >> >> >> >> >From what I can measure so far the relays seem to be working "as designed". >> When I switch from 15 meters to 40 meters I can see the pulses to the >> relays to switch them (latching relays. I did notice in the 4 band >> filter manual it says K6 relay is not active on 40 but I do see it >> active and looking at the schematic K6 switches between 15/20 >> operation and 30/40 so I think there is a typo in the filter board manual at >> the bottom of page 23. >> >> >> >> I am using a Marconi service monitor for testing. I have not built an >> RF probe yet and hoping someone has seen this symptom before. I would >> like to get the K1 fully operational as the proceeds are going to my >> Elmer's widow 100% >> ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
