[Amps] LK500-ZB

[R. David Eagle]

Paul...

That was I that was requesting the info about the neagtive grid current on the LK-500

I just got done working on mine.  I found last week that the grid shunt resistor was blown and someone on the list here suggested that it may be exactly that and it was!

I ordered a few from digikey and replaced it.....it is now running once again!  This amp was a new addition/project for me and I'm glad to finally see something come out of it.

Dave
KB8NNU




________________________________
From: Paul Decker <kg7hf at comcast.net>
To: amps at contesting.com
Sent: Wednesday, September 9, 2009 2:36:50 PM
Subject: [Amps] LK500-ZB



I saw a thread about LK500 and negative grid current.  Was that ever solved? 





My LK500-ZB is acting up.   OK, I think it is my fault, the amp was on, but in standby and I was in the shack hanging a picture and dropped the hammer ontop of the amp (cover on and all)   



No visible damage to the case, but now when the amp is turned on, but in standby, the plate current reads about 200mA and the grid current is pegged negative.  Plate voltage is lower than what it used to be, about 2600 V.   Switching between RX/TX doesn't seem to have any affect, I can hear the relay kick.   One final observation, in RX, one tube starts to glow orange, while the other stays the normal light yellow color.  



It seems as if maybe somehow the tube is internally shorted or something.   Ideas, suggestions.. 



thanks, 

Paul (KG7HF) 


_______________________________________________
Amps mailing list
Amps at contesting.com
http://lists.contesting.com/mailman/listinfo/amps