Hi Tom:
Yes...there are the lead arrangement issues but I accounted for them.
The typical EBC Vs ECB issue. Easy in this case because they used the
triangular hole pattern instead of the inline pattern on both the R4A
and B version modules.
Curt
On 2/26/2013 10:49 AM, Tom Holmes wrote:
HI Curt..
It almost sounds like there is a different lead arrangement on the 3393. Any
well designed circuit of that era would have had to tolerate the typical
high variability of Hfe to avoid tedious hand picking of parts, although
that may have been done in this case.
Tom Holmes, N8ZM
Tipp City, OH
EM79
-----Original Message-----
From: [email protected]
[mailto:[email protected]]
On Behalf Of Curt Nixon
Sent: Tuesday, February 26, 2013 10:40 AM
To: Drake Forum
Subject: [Drakelist] R4A-B Detector Amp Q5
GM All:
Has anyone else had trouble getting a general purpose sub working in the
Q5 AM
detector amp position?
I tried several close NTE GP subs and also a 3393 which is same parameters
ex
Hfe which is slightly different.
The transistor comes on but with the grounded emitter, pulls the collector
voltage
to near zero. As soon as I put in a "real" orignal
3394 from a R4A, it works as it should--good fidelity and collector
voltage at about
5V from the supply rail of 10V.
Is this design so sensitive to Hfe as to be marginal or need to be hand
selected?
Certainly the 3393 is well within the spec range of the 3394.
Thanks
Curt
KU8L
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