components. This is the VCO.
There is a small IF-can sized coil
labeled in the service manual
(available from www.w7fg.com) on
page 72, "PLL UNIT VIEW," identified
as T20. Due to vibration, the slug of
T20 can move, and this will cause
the VCO to go into an unlock mode
or shift the tuning of the VCO to the
hairy edge of being locked.
Dial in a known frequency (I use
WWV) and measure the VCO voltage
as per Kenwood's recommendation,
and gently (using a proper tuning
tool) rotate the slug and watch the
440S display. At some point, the
display will change from dots to the
frequency you selected. You should
hear the receiver come back to life.
You may have to tune the coil to get
the station you tuned in to be heard.
This is only a way of proving that
you can adjust the VCO back into
range to lock. You will probably have
to replace the parts as shown in the
ASB0973 bulletin. Retune the VCO
as per the service bulletin.
Chuck Reville K3FT
#2 BA282 diodes are stocked by
Surplus Sales of Nebraska. Their
telephone number is 402-346-4750.
#3 Two of the diodes you listed —
the BA282 and the 1S1587 — are
listed in the catalog of RF Parts, San
Marco, CA. I have not checked stock.
Their toll free number is 800-737-
2787. I have had limited dealings
with them, but they have proven very
Mark Van Sickle KG4ORA
NUTS & VOLTS
#4 These parts can be ordered
online from www.pacparts.com
The BA282 was in stock when I
checked for $1.74 each. I hope the
repair is successful!
Ann Arbor, MI
[100310 - October 2003]
I have a JVC handy-cam (
Mini-DV Model DVL 505). It has a small
battery that does not last long. The
JVC AC power supply (Model AAV-
40) for that camera has an
extension cable that will supply
DC voltage instead of the battery, if
desired. The book says that the
battery is 7.2 volts and that the AC
power supply puts out 6. 3 volts.
Can I power this camera with a 12
volt gelcell without damaging it? I
suspect I can because devices like
this can use automobile lighter
adapters that sell for about $15.00,
so, I doubt there are any magic
voltage regulation circuits in them.
#1 Don't plug that 12 V into your
little camcorder! There's a good
reason why the batteries and the AC
supply hang around 6 V. If you want
to run the camera off your 12 V
gelcells, do it the safe way, and
purchase the JVC AP-V8U car cord
designed for your camera ($49.00
Its specs say it's a 12 V in, 6 V
1.8 A out device, so yes, it does have
a regulator in it. Then, shoot by
www.partsxpress.com and pick up
a 265-235 cigarette lighter extension
cord. You only are after the nice cord
mounted socket, which you can cut
off, leaving a few inches of wire.
Crimp on a couple of 1/4" F-disconnects (095-300 from
partsxpress) which should mate with
your gelcells, and carefully check
polarity to make sure you are feeding
+ to the center of the lighter socket.
Plug in the car cord, and you'll feed
your camcorder its favorite flavor of
nicely regulated 6 VDC.
You'll probably find similar parts
at RadioShack too, but stick with the
JVC car cord.
La Grange Park, IL
#2 Rapid LLC makes the product
you need. It has been tested with JVC
cameras and works great. The
design of the product is based upon
TI's Integrated Switching Regulator. It
is a bad idea to simply put 12 volts
into an expensive device that
requires just 6. 3 volts.
The ISR is a high efficiency
voltage regulator that will provide the
correct voltage to your camera. This
product accepts input through a four
pin DIN connect. As a professional
cameraman, you will recognize that
as being the video industry standard
connector for DC power. Full specs
can be found at: www.digital
Jon B. Bushey
Salt Lake City, UT
[11031 - November 2003]
I am using a 4017 sequencer
IC to light a small Christmas
display, using the first nine steps
to light each element. On the tenth
step, I would like all nine outputs
to light up, and then repeat. I am
using relays ( 12 volts, 700 ohm
coil) to interface the IC and
display, but, I can't get the nine
outputs to light all at once.
Outputs for the 10 taps of the
4017 are T0=pin 3, T1=2, T2= 4,
T3= 7, T4= 10, T5=1, T6= 5, T7= 6,
T8= 9, and T9= 11. For each of your
relay inputs — which should be
connected to one of these T# points
— you need to insert a two-input "OR"
gate. If we name the relay coil wire
previously connected to T0 as "R0,"
then "R0" connects to the output of a
two-input "OR" gate whose inputs are
"T0" and "T9." "R1" connects to the
output of a two-input "OR" gate
whose inputs are "T1" and "T9". This
pattern carries through for the
remainder of the relays.
Typical "OR gate" ICs such as
the TI CD4071B only contain four
gates, so you would need three chips
to handle T1-T9. I have not tried this,
but I think you could do this much
cheaper by implementing your own
"OR" gates with a pair of diodes:
T0 ——|>|—— +
+ —— R0
T9 ——|>|—— +
Assuming that the voltage drop
across the diodes still leaves enough
voltage to drive your relay coils, this
should serve to isolate your inputs. A
Schottky diode such as a 1N5817 is
recommended to minimize the