Sorry, David, I was looking at the A Sweep Generator when I wrote that.
I was referring to R371 and D372, collectively across the C-B junction of Q373.
Dave Wise
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-----Original Message-----
From: TekScopes@...
[mailto:TekScopes@...] On Behalf Of David
Sent: Wednesday, October 10, 2012 5:09 PM
To: TekScopes@...
Subject: Re: [TekScopes] Re: Bright dots at start of the trace on a 547
I thought that resistor was for snubbing any oscillation when a low
impedance is present at both the base and emitter since the 2N2207 is
not slow. 47 ohms in series with a base is not usually significant in
other respects for a signal transistor.
I do not have either of the high voltage transistors I suggested
immediately handy but if Ren¨¦ has problems, I can pick some up and
break out my 547 to run some tests and make some measurements. I
gather from his posts that the unblanking is happening quickly enough.
In his place with a 2N2207 that died of old age, I would probably go
through and change all of them while checking for proper operation.
