Hi Don, all, Thanks for the help & suggestions. Pin 5 of U1 is 0.6v but CAL tPA cannot be adjusted. Looks like the MCU on the KPA100 is faulty. I've ordered a new one.
73 Ian G4FSU On 10/04/2008, Don Wilhelm <[EMAIL PROTECTED]> wrote: > Ian, > > Put the K2 into CW test mode (in CW, press and hold the MODE button), set > the power level to something above 11 watts - press TUNE and measure the > voltage at KPA100 U1 pin 5. The voltage will normally be close to 0.6 volts. > > If the above measurement is correct and you still cannot adjust CAL TPA, > then I suggest that you replace the KPA100 MCU. > > OTOH, If the measured voltage is substantially different than 0.6 volts, > check the KPA100 bias as instructed in the manual - if that is found to be > grossly incorrect, check R5, R6 and Q3 (refer to the schematic) to be certain > these components are receiving the proper voltages during transmit (use CW > TEST mode). > > 73, > Don W3FPR > > > Ian Greenshields wrote: > > > After repeating the power calibration on my K2 KPA100 due to low > > output power, I found the CAL tPA function had reset to 0C and can no > > longer be adjusted. > > > > Having pressed EDIT from the CAL tPA display, the display shows tPA > > 0C, but turning the VFO knob has no effect on the display, it remains > > resolutely at 0C. > > > > Scanning the archives dug up a couple of similar issues, but no > > solution. Has anyone seen this? Is the there a fix? Is my brain > > disconnected & I'm doing something stupid (most likely scenario, I'll > > admit)? > > > > I'm now concerned that having fixed the output power, the fan won't > > switch on when it's needed. > > > > > > > _______________________________________________ Elecraft mailing list Post to: [email protected] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
