Ashhar Farhan VU2ESE
— the polymath from
Hyderabad, India — whose
Bitx series of transceivers
has taken ham radio’s QRP
world by storm, is following
his recent Bitx40 success
by offering the impressive
Microbitx transceiver, also
known in ham radio circles
as the Ubitx (which we’ll
refer to it as here).
introduced the Ubitx to an eager market,
Farhan has been struggling to keep up
with the high demand for his new radio
while receiving reports from many users
that Ubitx’s audio chips are failing — some
(Figures 1 and
True to form, Farhan has wasted no
time in addressing the problem, but as of
this writing he’s been unable to nail down
the exact cause of the chip’s failure. He’s
also not able to say how many of the
defective chips have made their way into
the user community.
defective chips are from a
series marked “WX.” Farhan
is advising all users who
have chips from the WX
series to replace them with
a chip which is known to
work. Several users have
replaced the defective chip
with the JRC 2073D, and
others have used the very
reliable LM386. Be advised,
however, that the LM386
is not pin-compatible with
Ubitx’s chip and will require an interface
to be used.
Additional fixes for the audio chip
problem can be found on
most of them require somewhat complex
modifications to the main board.
Unfortunately, Farhan’s decision
not to use chip sockets and instead
solder the chips directly to the board has
unnecessarily complicated the repair.
Farhan stated on his website that the
Ubitx boards were thoroughly tested prior
to being shipped. Still, the defective chip
Meet the Microbitx:
A Simple to Build, Yet
Rarely has there been as much interest in a high
frequency radio as that shown to the Microbitx.
Low power enthusiasts — better known as QRP
operators as well as ham radio hobbyists — have
rushed to place their order for this exciting and
challenging new transceiver kit.
1. Blown audio chip from a MicroBitx transceiver.
2. Another blown audio chip.
By Steve Jackson
62 September/October 2018