Do you have the ALC hooker up? Kurt
> On May 31, 2019, at 4:21 PM, William Stewart <[email protected]> wrote: > > All, > > I am trying to bring a Drake L-4B to life. I have done the power supply > rebuild, the soft-start and other mods. I have also directly grounded the > grids of the 3-500Zs (Eimac brand). In driving it with my K3 (SN 51XX, > software up to date) I find that the RF power stair-steps to the set power in > a hesitating way over a few seconds. This happens sending Morse code or using > the "Tune" button. > > The supply voltage, as monitored on the K3 display, is at about 13.4 volts > when transmitting. > > I have a power/SWR meter between the K3 and the amp and it shows a low SWR at > all times, as does the K3 SWR meter. > > The power meter between the K3 and the amp shows the power gradually > increasing. As the K3 increases power out, the amp power out increases in a > similar fashion. > > I see no indication of oscillation. The power meters on the output side of > the amp show no power when the amp is keyed but no RF is supplied. I placed a > low-pass filter (41 MHz cutoff) between the K3 and the amp to no effect. > > I notice that if I send a series of Morse code characters such that the K3 > transmit delay timer never times out, once the power ramps up to the set > value, it remains solid until the timer expires - when I start transmitting > again, the power step process repeats. > > When I put the amp in Standby, the K3 functions normally. > > This smells like an oscillation problem, but I see no evidence of one. > > Any advice would be appreciated. > > Thanks, > > Bill K5EMI > > > ______________________________________________________________ > 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 ______________________________________________________________ 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
