Don - do you mean diode across the K6 and K7 relay coil or do you mean connect at the NO contact of K5 ? From schematic in Rev E Owner Manual, it looks like K5 normally open contact provides 12T that connects to both K6 and K7 coils. The PN2222 preamp + MAR3 are powered by same 12T, and I expect a negative spike would be bad there.
At 08:48 PM 2011-07-30, Don Wilhelm wrote: >David, > >Well, most all XV transverters out there have this problem and operate >without obvious symptoms. The situation is that there is no diode >across the K5 coil to absorb the "kickback" voltage from the relay coil >inductance when the power to it is removed. If you find the time >between transmit and receive slowed, then that change will help the >situation. Actually, there is a path present through the contacts of >K4, so the diode is still doing its job as long as K4 remains closed >(and it normally will). It is just better to have the diode connected >directly across the K5 relay coil. > >All I am saying is that if you get a chance to remove the bottom cover >for any reason, that is a good time to make the modification - if there >is no reason to remove the bottom panel, then leave it as-is for now. > >73, >Don W3FPR > >On 7/30/2011 7:31 PM, KJ4YQK wrote: > > I replaced Q2 and now I have the voltage on R16, and I am able to > change the > > Receiver RF Ap bia. Starting it off at 179 mV. I am able to get it above > > 200 with no problems. One transister off, at least I have two good > > transisters nwo. > > > > Updating the Schematic now for the IF and Control circuits. > > > > I plan on getting this up on the air tonight, maybe in time for > the local 2 > > meter net. > > > > Thanks for helping me out, this really gave me a good look at the circuits. > > I will write some notes on it. > > > > I will look at the correction you mentions abt the circuit board. What > > effect does that have on the operation of the unit if left as is? > > > > David > > >______________________________________________________________ >Elecraft mailing list >Home: http://mailman.qth.net/mailman/listinfo/elecraft >Help: http://mailman.qth.net/mmfaq.htm >Post: mailto:Elecraft@mailman.qth.net > >This list hosted by: http://www.qsl.net >Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
