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Title: B&W 5100 PA tuning question... Post by: K1ZJH on April 29, 2009, 11:50:02 AM I'm not sure I'm reading the manual correctly.
What is the recommended grid current for the 6146 PA tubes? Pete Title: Re: B&W 5100 PA tuning question... Post by: Joe Moore on April 29, 2009, 12:57:53 PM My manual says to load it up to 220ma as read with the meter switch
in the AMP. position. Title: Re: B&W 5100 PA tuning question... Post by: Joe Moore on April 29, 2009, 12:59:25 PM And the Grid to around 17mils.
Title: Re: B&W 5100 PA tuning question... Post by: K1ZJH on April 29, 2009, 01:06:16 PM And the Grid to around 17mils. Bingo! Yeah, but isn't almost 8 mA grid #1 per tube way over the max ratings for a 6146?? That's what I read too. Or does the "metering reading" a relative scale type of indication? Pete Title: Re: B&W 5100 PA tuning question... Post by: WQ9E on April 29, 2009, 05:14:32 PM One of the B&W 5100B's oddities is that it monitors the final screen instead of control grid current. I believe it runs around 220 volts on the screen so 17 mils is approaching the maximum rating for a pair of 6146 tubes (2 watt screen dissipation per tube). So 17 mils is safe but don't go way over this to keep the final tubes happy.
Rodger WQ9E Title: Re: B&W 5100 PA tuning question... Post by: K1ZJH on April 29, 2009, 05:19:06 PM Thanks Roger, that makes more sense. In many ways the manual is a train-wreck. Not very well organized or written. I'm still muddling my way through it. AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands
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