=  NOW 30 WPM  =  TEXT IS FROM DECEMBER 2022 QST  PAGE 44 =

CHECKS FOR POWER BUS SHORTS.  THEN CONNECT AN ANTENNA AND SPEAKER OR
HEADPHONES, APPLY POWER, AND LISTEN FOR SIGNALS ON THE FOUR BANDS WHILE
CHECKING OPERATION OF THE DISPLAY AND CONTROLS.  AT THIS POINT, THE
RECEIVER SOUNDED DEAF, SO I STOPPED THERE TO RECHECK MY WORK.  BECAUSE OF
THE WAY THE BOARD INTERCONNECTIONS ARE DONE WITH THE TWO 16 PIN CONNECTORS,
IT WAS EASY TO POP THE BOARDS APART AND INSPECT EVERYTHING WITH A MAGNIFER,
REVEALING A BAD SOLDER JOINT ON THE FILTER SWITCH.  WITH THAT FIXED, THE
RECEIVER SOUNDED FINE ON ALL BANDS, SO I MOVED ON TO THE FINAL ADJUSTMENTS
WITH THE RADIO CONNECTED TO A WATT METER AND DUMMY LOAD.  SEVERAL TRIMMER
POTENTIOMETERS NEED TO BE ADJUSTED.  THE FIRST TRIMMER IS SET TO JUST
BARELY LIGHT THE BLUE SIG LED WITH NO SIGNAL PRESENT.  IT GLOWS BRIGHTLY
WITH STRONG RECEIVED SIGNALS.  THE NEXT STEP REQUIRES A MULTIMETER IN
SERIES WITH THE POWER SUPPLY THAT CAN MEASURE CURRENT OF AROUND 100 MA WITH
A RESOLUTION OF A FEW MILLIAMPS MOST DIGITAL MULTIMETERS WILL WORK HERE.
IN THIS MULTISTEP PROCESS, WATCH THE CURRENT DRAW WHILE ADJUSTING THE BIAS
TRIMMER TO SET THE OPERATING POINT FOR THE FINAL AMPLIFER FET.  THIS SHOULD
=  END OF 30 WPM TEXT  =  QST DE W1AW  <