[Amps] amp supply lk500 za

[Charlie Young]

KE3C wrote: 
 
> I replaced my fan with the AL80B fan from Ameritron. It is a little under
> capacity compared to the original. I supplement it with a 23 volt
> computer fan when I am contesting.
> 
> Ken KE3C

 
Just make sure the replacement blower makes enough air to keep the tube socket filament pins cool.  I picked up an LK500Z  at an estate sale.  It came with several 3-500 tubes which had desoldered filament pins, plus the tubes in the amp would not light.  The socket filament connections had been so hot the spring tension in the clips was lost, so there was  insufficient contact. 
 
I resoldered the tube filament pins and replaced both sockets.  The blower was running too slow due to an open dropping resistor.  I sold the repaired amp to a friend who needed one, and it is working great.  However, I advised him to run the blower on high speed all the time.  I would have if the amp were in my operating lineup. 
 
This was a nice, compact amp in great cosmetic condx.  My friend is happy with it.  
 
Not sure if this is a common problem in these amps that use air blowing horizontally across the tubes  but it was the case with this one.    
 
73 Charlie N8RR