Pat
Here is my thought. Everything may be just fine actually. This looks like
the same approach used on older technology even the transistor. Its job is
to run class AB1 and boost the signal to something like +27 dbm. Lots of
power.
The reason is these then typically drive a passive 8 or 16 way
Hi
I would second Paul’s input. Is the unit actually working at the moment? Some
of the circuits in these gizmos *do* run pretty hot in normal operation.
If there is a problem with that device, before I paid $67 for the replacement
part
(or anything close to that) I probably would convert it
Hi Dan,
That would be a MMIC amplifier. Transistors have Q reference
designators. U's are ICs. Take a look on the other side for markings.
It appears to have been mounted upside-down.
David N1HAC
On 1/10/18 12:22 PM, Dan Kemppainen wrote:
Patrick,
It's possible that's one of the
Thanks for the idea, Francis. I hadn't considered that. I'll keep that in
my kit bag as I work to resolve this. And I agree the temperatures of the
regulator and transistor are connected. I believe the regulator is
providing the bias. Given the output is some 27DB, that is a lot of
dissipation for
Patrick,
It's possible that's one of the integrated RF amps, and not just an RF
transistor.
You should be able to tell by tracing out the circuit. The inputs and
outputs will typically be capacitor coupled, with DC fed to the output
through a chip inductor or similar choke and resistor.
If I recall there are 2 MMIC chips, the large one you mention (U105) and
a smaller black plastic one (U100) to the left of the big one and to the
right of the 15 Mhz crystal filter. Just above the chips you will see 2
inductors marked L101 and L102 that supply the d.c. power to the chips.
The
And for anyone working on the 10544 oscillator, Charles Steinmetz writes:
> The errors HP made in the 10544 schematics are grave enough that it may
> be a good idea to post my corrected schematic wherever folks who need to
> work on the oscillators are likely to look for service information, so
