Gents, Any idea what fault would cause my old and previously faithful Amp Supply Co LK550 sometimes to register ~400mA of plate current and negative grid current, even with no PTT and no drive? First
Any idea what fault would cause my old and previously faithful Amp Supply Co LK550 sometimes to register ~400mA of plate current and negative grid current, even with no PTT and no drive? A bad tube w
It sounds like a problem on the relay board, a bad electrolytic, sticking contacts are the most common. This is not good for the tubes so get out the tools. Another possibility is tube gas which is n
If the plate current is 400 ma, then at least one tube is conducting. Mine registers slightly negative grid current when it is not transmitting, so that is not the issue. I would say that it is oscil
Thanks Ken - and sorry for the long pause. I've noticed that the anode choke is cooked so that will be replaced "soon as" as we say in ZL. I have one on order from Ameritron, now MFJ. Meanwhile, I ha
You might want to consider how the plate choke got fried in the first place. I've had that problem with an LK-550ZC. It was caused by an arc from a bad tube. I believe the tube's vacuum was compromis
Thanks Dick. While thankfully I haven't had to duck any flying crockery lately :-) I suspect I might have fried the anode choke by running the amp on 30m (using the 20m position since it has no WARC
Depending upon the model production date there are up to 2 unused bandswitch positions( 6 was the basic and the switch supports 8 positions); some were factory configured to add 12 and 17M. If you ha
Take a look at the choke in these photos. http://s863.photobucket.com/albums/ab196/knicely1/LK%20500/ That is what my choke looked like when I purchased my LK500. I would say you should replace the c
The Amp Supply chokes are 110uh and designed to be part of the 160M tank. The bypass cap is supposed to stop any small amounts of RF from getting into the PS but is too small a value IMO; I add a .00