I'm having some problems with some oscillations in the low noise
amplifier of my 11729C with serial prefix 2329A.
The frequency is around 27MHz, and I beleve it is from the pre-amp
section of the low noise section. Mixing products of this are also
appearing as low frequency modulations on the detected noise.
Since my testset is older than the available manuals (2509A), I was
hoping someone had one for the earlier version, either for sale or
available for scan?
As far as I can determine, all the ferrite beads are in place, as well
as the decoupling capacitor, although I question the usage of only
electrolytics as decoupling in a amplifier with response 10Hz-25MHz.
The transistors used has a Ft of 2.4GHz so I guess a next test may be
to parallel the electrolytics with some smaller ceramic capacitors.
Have anyone seen this problem before? any hint on where to go forward
is appreciated.
BR.
Thomas.
--
With Best regards, Thomas S. Knutsen.
Please avoid sending me Word or PowerPoint attachments.
