[Amps] Purpose of cathode resistor?

[Vic K2VCO]

Bill Turner wrote:
> I have a question for all the amplifier experts out there.
> 
> In this schematic:
> 
> http://members.ispwest.com/dezrat1242/cathode.jpg
> 
> there is a 250 ohm resistor connected across the fuse/zener. What is 
> the purpose of that resistor, and why is that particular value 
> chosen? (I have also seen 200 ohms used.)

My non-expert guess:  if the fuse blows, it prevents the filament 
transformer secondary from rising to a very high positive voltage, 
possibly exceeding it's insulation rating.
-- 
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco