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Old 08-22-2006, 02:41 PM
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wa2ise wa2ise is offline
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Join Date: Dec 2002
Location: USA
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Quote:
Originally Posted by Chad Hauris
I think this is a series string filament set which does not use controlled heater warm up time tubes so there is a surge of current in some tubes (such as the CRT) when the set is turned on and is hard on the CRT filament...replacing the CRT filament in the string with a resistor and providing a seperate trans for the CRT filament removes the surge problem from it.
Another possibility would be to use a pair of high powered zener diodes (in series, cathode to cathode) rated for around 8V (this value selected to pass the peak voltage of 6.3VRMS = 8v +0.7V diode drop of the other zener in forward conduction mode). So when the set is turned on, the diodes will clamp the heater voltage to around 8V equivalent RMS, which a heater is designed to take for short periods of time. It is a *heater*, not a filament, yes?

You can hide the diodes below the chassis.
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