The first thing to do with any TR-7 suffering from strange problems is to check for dirty/oxidized Molex pin connectors between the plug-in cards and the parent board. Often simply exercising them by unplugging and plugging back in a couple of times is enough. Also highly recommended is to replace the electrolytic cap(s) on the VR board while you're "in there".
Despite it's apparent complexity, the TR-7 is actually pretty simple in the way it works. :) 73 -Jim NU0C On Wed, 27 Jun 2012 10:21:36 -0700, k6uo wrote: >To all the helpful folks on the list, > >I have a number of Drake radios and recently I was given a TR7 with audio >problems. Upper and lower sideband >sound the same. I have a service manual and a set of extender boards. The 10V >adjustment is exactly 10 Volts and >the 40 MHz oscillator is 40 MHz, the VCXO is 53.695. The 8.05 MHz oscillator >is where Iâm having problems, >following the instructions in the manual, I see 10.564 MHz at pin 40 and C1030 >doesnât have much effect. >Sideband audio sounds like itâs on the opposite sideband, the adjustments on >the VR board donât change >the audio. >I have a fairly good background in repair, but you know about the age thingâ. >Any help and guidance will be greatly appreciated. -- 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://incolor.inetnebr.com/jshorney http://www.nebraskaghosts.org _______________________________________________ Drakelist mailing list [email protected] http://mailman.zerobeat.net/mailman/listinfo/drakelist
