[Amps] L4B Plate choke

[Wayne Rogers]

I just opened up my L4B to do some minor work on it.  I noticed that the plate choke looks like it has overheated - discolored brown around the middle of it.

Wonder if anyone has experienced this - common problem with the L4B?  Or a symptom that something is wrong?

The amp works fine otherwise - good power out, no sign of parasitics.  I do work it hard in contests, and run full power in CW.

Wayne N1WR