Not sure, I must have inadvertently applied 12v somewhere I shouldn't have. Either way, I doubt that I can check any further damage until I replace D7. Probable worst case would be having to drop $40 on new 2n2219s.
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-------- Original message --------
From: "Gordon Gibby KX4Z via groups.io" <docvacuumtubes@...>
Date: 3/1/25 5:19 PM (GMT-05:00)
Subject: Re: [BITX20] reviving my sbitx v3
Michael, how did D7 get damaged?? ?Was reverse polarity applied to the radio at some point?? ?that would be the most likely way to damage D7 and it would have serious impacts on some of the
other components, such as the 4 transistors in the driver section.? ?So what do you know about how D7 got damaged???? it isthere?to protect somewhat against?reverse polarity
Gordon?
On Sat, Mar 1, 2025 at 3:01?PM Michael Bales via
<mikebales73=
[email protected]> wrote:
So, after the diagnosis and repair of the power group components, Q9,Q10,Q101,R5,R6 (all replaced), on power up, +12v drops to under 2v and the area around the Q12-15 group heats up quickly. I did note that D7 was basically shot, continuity in both directions.
What are my most likely culprits at this point?
--
Mike - K8MCB?
--
Mike - K8MCB?
