OK Craig, I think you have a diva there. Talk to her gently, in low, soothing tones. :)
Two possibilities come to mind. The plastic meter case may have acquired a static charge. Have you cleaned the front plastics recently? Vigorous rubbing can excite the electrons too much. This should show as a non-zero reading with the radio powered off. The other possibility is the mechanical zero of the meter movement needs readjusment. Again, does it rest at zero with power off? If so, that's not your problem. This adjustment is accessible from the front of the meter case, which means you have to dismount it from the front panel. Be aware of the potential for static charges while you are doing this, it can throw off the adjustment and you will be frustrated again. The null adjustment on the watmeter board balances the SWR bridge so that you have zero reflected power with a 50 Ohm resistive load. It shouldn't require readjustment, but if you have a good, accurate dummy load, it couldn't hurt. It wouldn't be the source of your problem, however. 73 -Jim On Sat, 20 Feb 2010 20:39:59 -0500, Craig Roberts wrote: >Hmmm. The 10 volt line is dead on (I equipped the power supply board >with trim pots). The S-meter has been re-calibrated correctly with no >fuss and the power meter adjustments have been made successfully. Yet, >the reflected power still indicates below zero when the transmitter is >keyed -- as if the meter was wired in reverse. > >What about the "null meter" adjustment on the AL:C board? What does >that do? (Yeah, I know -- it nulls the meter). -- Ham Radio NU0C Lincoln, Nebraska, U.S.S.A. TR7/RV7/R7A/L7, TR6/RV6, T4XC/R4C/L4B, NCL2000, SB104A, R390A, GT550A/RV550A, HyGain 3750, IBM PS/2 - all vintage, all the time! "Give a man a URL, and he will learn for an hour; teach him to Google, and he will learn for a lifetime." HyGain 3750 User's Group - http://groups.yahoo.com/group/HyGain_3750/ http://radiojim(dot)exofire(dot)net http://incolor.inetnebr.com/jshorney http://www.nebraskaghosts.org _______________________________________________ Drakelist mailing list [email protected] http://mailman.zerobeat.net/mailman/listinfo/drakelist
