[Amps] TL-922A questions

[Rich]

  If you want to discuss the 922, phone me. 

>Hi Guys,
>I purchased a TL-922A recently and found it has a problem.. Can anyone
>help me
>figure out what's going on?
>The first time I fired it up (using a TS-830S to drive it)  I made the
>mistake of having
>it in the SSB position once to measure the carrier output....  

The 922 does not have a hv-ps that is designed for carrier/locked key 
operation.  
A keyer sending 50wpm dits is a better way to go.  


>Started to smell funny !
>Bad idea !     Put it back in CW position and measured output with 200ma
>drive at
>about 600 watts..  Started to smell funny again.   Reduced drive to
>100ma and
>it seems to behave with only about 500 watts output.  (peak reading
>meter)
>My first thought was (and still is)  that one of the tubes was shot...
>Having no way to test the 3-500z's and before I invest in new tubes,  I
>need some
>expert advise.   Does this sound like a bad tube to you guys?
>
>I'm running it with on it's own 240VAC circuit and driving it with a
>TS-830S.  I can
>tune to perfect swr with my Matchbox and balanced fed antenna.
>
>I took the bottom off and observed that both tubes have filaments lit..
>( I have heard that
>there is a problem with high filament voltage with these amps and intend
>on making the modifications that Rich Measures recommends.)    Nothing
>appears
>to have been burned.  All looks clean and normal...   Where could the
>smoke been coming from?   

When a tube shorts, the unfused filament transformer will melt down 
during standby unless the resistor-cutoff bias mod has been made.  
SB-220s suffer from the same malady..  

>  I'm getting a little soured on this rig ...

With a few semi-simple mods, the TL-922 is a winner.  

-  Rich..., 805.386.3734, www.vcnet.com/measures.