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Title: globe 680 Post by: ki4ndb on August 24, 2009, 07:41:49 PM i have a friend that is tring to get a globe king 680 finished, he has ran into a problem as long as the rig is out of the case it has clean audio but just as soon as he slides in the case the audio changes & he says it has a hum. has anyone ever had this problem?. thanks for reading. 73's
Title: Re: globe 680 Post by: KC4VWU on August 24, 2009, 08:12:49 PM That's kinda strange, but I guess anything is possible.
My first guess would be that maybe when it is put in the cabinet, somthing is touching that should not be. I believe the chassis slides in from the front, right? Or possibly if the srews are tightened and the chassis may be in a slight bind possibly separating a broken ground connection. Mechanical type problems. The other thing is,are all the correct tubes inplace and not just substitute #'s. Do any have tube shields missing? Maybe some of the wise ones have some rig specific cures. Good luck! -- Phil KC4VWU Title: Re: globe 680 Post by: WQ9E on August 24, 2009, 08:16:24 PM Does he have the ground connected the same way when it is in and out of the case? Is the case distorting the chassis causing a bad connection to become a problem when it is in the case? Try carefully flexing the chassis when it is out of the case (taking care not to fry himself) to see if he can make the problem appear.
I had a Johnson Challenger that worked perfectly outside of the case but the cheap loading condenser would short with the case (pristine with no dents or structural flaws) in place. I had to bend a few plates to make it work properly. Title: Re: globe 680 Post by: N3DRB The Derb on August 25, 2009, 03:12:29 AM I bet you have a ground that not a ground. Start looking in your low level audio stages first.
does the rig have hum in cw mode? if so, you know its not audio stage specific. slide it in there op it on cw and see how your cw note is. If it is hum modulated it has nothing to do with audio. bad grounds, rusty hardware. he does have a 3 wire grounded plug on it,right????? never ever operate any of this old crap on a 2 wire cord. Good way to die given the right circumstances. Title: Re: globe 680 Post by: ke7trp on August 26, 2009, 03:34:01 AM I agree... Ground problem.. AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands
Take this advice first hand... I got a D104 at a ham fest.. It had the 2 pin plug on it for my Globe Champion. I got home, Plugged this D104 in to the early Globe 300.. Grabbed the D104 to key it down and thats all I remember. 11 The Globe has 117 volt relays in it. The previous owner of d104 rewired the mic in a way that worked for his Soldi state rig.. For me.. in the old Globe, It put Full main voltage through my arm. Clark |