Re: Bitex40 power output.
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I am trying to trouble shoot low power output on my friends BITX-40 that he built a couple months ago (latest version?) with a VOM after he lost full power.? It now, barely, moves a low range watt meter!? I bought one also at the same time and mine is working fine.? I did the voltage checks and toroid connections, that Jerry, KE7ER, had posted and got seemingly, similar?results.? My friend had replaced Q13 with a 2N3904, but no change.?What might I (we) do next?? Receive, however, is good.? 73, Karl, KO8S
On Thursday, August 17, 2017 12:05 PM, Keith VE7GDH <ve7gdh@...> wrote:
Soundar VU2RJW wrote...
> Three times replaced Q13,14 and 15 but no result
> Finally found that? the R141? resistor value going
> on increasing and found 123ohms as on today.
Thanks for posting that. I just checked R141. According
to the drawing, it should be 10 ohms. I'm measuring
almost 60 ohms there. It won't be surface mount, but
I'll see if I can find anything close to 10 ohms here.
Bonus... R141 has a "burnt" look to it and I can't
read the number on it.
Good timing. My hot air soldering station finally
showed up two days ago. That should make things a bit
easier.
PS - I previously replaced Q15 and then Q13 (with a
TO-92 2N3904) with the same results as you. I do
have a 2N2219A (Q14) here but hopefully it isn't
needed. R142 looks OK (close to 1K) but R143 reads
low (300 ohms or so) but that's measured in the
circuit with it still connected from the base to
the collector.
--
73 Keith VE7GDH
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