I didn't assume it was just a silent "A" and it does make a difference :-)
In the R-390, the break-in relay is K-602 and the Squelch relay is K-601. In the R-390A the Break-in relay is K-601 an there is no Squelch relay. There are differences in how muting is effected in the two radios as well, since the R-390A does not use an interstage transformer to drive the line and local amps. But the general notion of getting control voltage to the break-in relay is similar. Grant/NQ5T On Dec 2, 2009, at 12:31 PM, rbethman wrote: > The cited References are for the R-390A. > > John, which is it you have? > > *IF* it is the R-390A, then the break-in relay *IS* K-601 in the AF Module. > > Bob - N0DGN > > Grant Youngman wrote: >> On Dec 2, 2009, at 10:46 AM, John King wrote: >> >> >>> Thanks for the source of information, Jerry. I have looked at the schematic >>> on the Y2K site and see relay 601, the break in relay. Now I must >>> physically locate it and determine if the relay is indeed bad. I have 12.95 >>> vac at terminal 9 on the terminal board on rear of R390. >>> >> >> Not sure of the age or condition of your 390, but you might also just try >> pulling and reseating P120/J620 on the audio chassis. Among other stuff, >> this connector carries the operating voltage to the Break-in relay, K-602. >> (K-601 is actually the squelch relay). Both relays just ground the audio >> out from the AF amplifier V-601 through the interstage transformer T-601. >> >> Pins 1 and 2 of P120 carry the control voltage to the relay. You could >> measure the voltage there also, to make sure it's getting that far along >> when pin 9 of the rear connector strip is grounded. ______________________________________________________________ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: AMRadio@mailman.qth.net To unsubscribe, send an email to amradio-requ...@mailman.qth.net with the word unsubscribe in the message body. This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
