[Kenwood] TS-520SE receiver brain teaser

2004年2月25日 19:20:09 -0600

I have a TS-520SE that has a strange problem.
As ridiculous as it may sound I have a 520 that when ever you screw the 
coax onto the connection it "dumbs down" the receiver and makes the rig 
basically useless. Currently I am allowing my Father to use the rig for 
listening in hopes he will become inspired to get his ticket. Currently 
I have a length of speaker wire simply stripped and poked into the 
center of the socket and it hears very well on all bands.
Now for those of you that are thinking that the coax is obviously 
bad/shorted/whatever. I tried 3 separate pieces of coax from working 
environments and it acted the same and for a final curiosity I tried 
just a naked PL-259 with nothing on it and it did the same thing. With 
only the center pin of the PL-259 inserted everything sounds great, but 
as soon as the shield portion of the PL-259 makes contact the receiver 
looses all sensitivity. Now I am a young fellow and I have not seen it 
all, but this seems awfully strange ... to me there seems to be no 
reason that this should happen, but I am always willing to learn 
something new. I tested the connection on the radio and it shows for 
lack of a better VOM a dead short, I looked at the schematic of the 
radio and I am somewhat visually disabled but I believe I traced down 
far enough to determine that in receive(as well as receive) the 
connection lead into a coil and eventually to a chassis ground on either 
side and I suppose should show a short as such.
The rig is as I stated a TS-520SE (no RF ground attached)
The antenna I supposed would be a random wire
There are no other attachments to the radio other than a DG-5 that at 
this point I can see has no reason why or how it could possibly affect this.
I hope that I am not the only one scratchin' my head on this one, but I 
hope there is someone that has encountered this and knows the solution.
Thanks for the consideration and reading along.
73
Tim KD5CKP