[Drake] BFO In R4C

[Garey Barrell]

Hi Gary

	Yes, the radio was working just fine and the BFO quit.

	I replaced the 2N3394 with a 2N3393 and still no oscillation. I used
a scope to check for 50kHz at T11 and nothing is there. Tuning the passband
tuning doesn't change anything either.

	I'll try tacking a cap across C85 and C89 as you suggest - if either
was open it would certainly kill the oscillator.

Paul

-----Original Message-----
From: Garey Barrell [mailto:k4oah at mindspring.com]
Sent: Monday, November 24, 2008 2:59 PM
To: Paul
Subject: Re: [Drake] BFO In R4C

Paul -

Has it EVER worked for you? I don't think I've ever seen one fail! :-)

Have you tried adjusting the Passband Tuning to see if it will oscillate
"anywhere"??

Just on experience I would suggest tacking a new cap across C85 and C89.

Possibly a shorted diode at CR2 or CR3.

73, Garey - K4OAH
Glen Allen, VA

Drake 2-B, 4-B, C-Line & TR-4/C Service Supplement CDs
<www.k4oah.com>



Paul wrote:
>
> All
>
> I've got an R4C on the bench with a BFO that isn't running.
>
> Q5 was replaced with no luck.
>
> Emitter volts = 4.33
>
> Base volts = 4.99
>
> Collector volts = 11.42
>
> So, it doesn't look like a DC problem. The radio was working fine one 
> day and then just quit.
>
> Other than replacing Q5 again, does anyone have any ideas?
>
> Thanks
>
> Paul
>
>


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