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[AMPS] SB-220 Glitch Resistor ???

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Subject: [AMPS] SB-220 Glitch Resistor ???
From: rjohnson@ici.net (Bob Johnson)
Date: Mon, 27 Nov 2000 18:04:27 -0500
Hi:
I'm getting ready to put a NEW old SB-220 on the air that has been sitting
around unused for 15 years.

The unit has been slowly brought up on a variac and run for a week with the
plate connections to the 3-500Z's disconnected.

The capacitors have been checked and the voltage drops across bleeder
resistors all fall within 5% so I plan to replace them with 75 ohm 5W MOX
resistors.

The old red grid bypass capacitors have been replaced with 120 pf Silver
Mica caps.

So my last mod before shooting the juice to the finals is to add the
"Glitch Resistor" !!!

It has been recommended on this reflector that RFC-2 be replaced with a 15
to 20 Ohm real enamel wirewound resistor.

My questions are:
Is 15 to 20 ohms "Cast in Stone" ?
Would 25 ohms be OK ?
What wattage should be used ?

I have checked the Mouser catalog and they stock the OHMITE Series 270
Power Resistors in 15 and 25 ohms for the 25 Watt version (L25J).

If this resistor is suitable, would it be better to go with the 25 ohm
value on the basis that the peak discharge current would be lower or would
the higher resistance cause other unforeseen problems ?

Please NO PARASITIC discussions on this message !!!

Thanks in advance to all.
Bob - WA1OFR



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