Proper ALC operation is a balance between the setting of the ALC level pot and the setting of the gain pot on the predriver board, which is located on the PA block. Drake service manual spec is to set the ALC pot for 140-150 watts output (into a dummy load) on 20 meters, in CW mode with the carrier level control fully CW. Then, on 10 Meters, set the predriver gain pot to the point where the ALC light *just* comes on. You may need to vary the 20-Meter ALC level up or down a bit (but never over 150 Watts) to get good ALC on 10 meters.
There is an alternate adjustment procedure at http://www.zerobeat.net/drakelist/tr7bookalign.html . I have had good luck using the service manual procedure, but YMMV. If neither of these procedures produce the desired result, you probably need to start looking at the ALC circuit or the forward/reverse power sensor (wattmeter) circuit. 73 -Jim On Sat, 13 Mar 2010 13:04:33 -0800 (PST), Jim DiMauro wrote: >Hi All: > >I just noticed an issue with the ALC light on my TR-7. >On the 10 and 20 meter bands the ALC light never comes on, regardless >of how high the mic gain setting is. Power and audio output both seem >normal on those bands, but the light doesn't come on. The light >operates normally on all other bands. Any ideas on what's up with that? > >Thanx & 73, > >Jim >W2BVM > > > > > >_______________________________________________ >Drakelist mailing list >[email protected] >http://mailman.zerobeat.net/mailman/listinfo/drakelist -- 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
