Ramsey Electronics FM30 User manual

FM30• 1
DIGITAL FM
STEREO
TRANSMITTER KIT
Ramsey Electronics Model No. FM30
• Synthesized 87.9MHz to 108.1MHz for no frequency drift! Direct
digital input of frequency, no jumpers or DIP switches!
• Designed for extruded, rugged metal case, all lines have RF
chokes, and fully regulated for the cleanest sounding low noise
performance yet!
• BNC style RF output for easy, reliable connections.
• Fully digitally controlled transmit power for custom coverage
capabilities!
• Digital volume and balance controls for easy audio level
adjustments.
• Runs from 13.8-16VDC, includes 15V DC adapter.
• Quality of signal indicator lets you know when you have a good
signal or over-modulated signal. Lets you know when to turn it up,
or down!
• Great for schools, health clubs, yard casting, drive-in movie
theaters, haunted rides, amusement parks, churches, etc!
A new and improved version of our popular stereo transmitter
kits, the FM30 is an ideal upgrade for improved performance
and ease of use! With a low-noise design and a metal case, the
FM30 suffers from much less interference for a better S/N ratio.
The FM30 also has full digital front panel control of output
power, volume, balance, stereo/mono, and frequency!

FM30•2
PARTIAL LIST OF AVAILABLE KITS:
RAMSEY TRANSMITTER KITS
• FM10A, FM25B, FM30, FM Stereo Transmitters
• FM100B, FM35 Professional FM Stereo Transmitters
• AM1, AM25 AM Broadcast Band
Transmitters
RAMSEY RECEIVER KITS
• FR1 FM Broadcast Receiver
• AR1 Aircraft Band Receiver
• SR2 Shortwave Receiver
• AA7 Active Antenna
• SC1 Shortwave Converter
RAMSEY HOBBY KITS
• SG7 Personal Speed Radar
• SS70C Speech Scrambler/Descrambler
• TT1 Telephone Recorder
• SP1 Speakerphone
• MD3 Microwave Motion Detector
• PH14 Peak hold Meter
• LC1 Inductance-Capacitance Meter
RAMSEY AMATEUR RADIO KITS
• HR Series HF All Mode Receivers
• DDF1 Doppler Direction Finder Kit
• QRP Series HF CW Transmitters
• CW7 CW Keyer
• QRP Power Amplifiers
RAMSEY MINI-KITS
Many other kits are available for hobby, school, scouts and just plain FUN. New
kits are always under development. Write or call for our free Ramsey catalog.
FM30 Digital FM Stereo Transmitter Kit
Ramsey Electronics publication No. FM30 Rev. 1.3a
October 2004
COPYRIGHT ©2004 by Ramsey Electronics, Inc. 590 Fishers Station Drive, Victor, New York
14564. All rights reserved. No portion of this publication may be copied or duplicated without the
written permission of Ramsey Electronics, Inc. Printed in the United States of America.

FM30• 3
DIGITAL FM STEREO
TRANSMITTER KIT
Ramsey Publication No. FM30
Manual Price Only $5.00
TABLE OF CONTENTS
Introduction..........................................4
Circuit Description................................5
“Learn as you Build”...........................10
FM30 PC Board Parts Layout............11
FM30 Parts List..................................12
FM30 PC Board Assembly Steps......14
FM30 Schematic Centerfold..............20
FM30 Setup.......................................26
Antenna Ideas....................................29
Appendix A: FCC Rules and Info.......31
Appendix B: .......................................33
Summary ...........................................35
Warranty ............................................39
KITASSEMBLY
AND INSTRUCTION MANUAL FOR
RAMSEY ELECTRONICS, INC.
590 Fishers Station Drive
Victor, New York 14564
Phone [phone]
Fax [phone]
www.ramseykits.com

FM30•4
INTRODUCTION
The Ramsey FM30 is a true SYNTHESIZED STEREO FM broadcast
transmitter, which any person may build and use in accordance with the rules
of their nation’s telecommunications authority. For U.S. residents, that
authority is the Federal Communications Commission (FCC). The FM30’s
low-power broadcasting capability and other practical uses can be fun and
interesting for people of all ages, but the FM30 is not a toy. We will refer to
the FCC regulations frequently in this manual and provide you with some
information necessary to enjoy the FM30's capabilities in accordance with
the law.
Typical uses for the FM30 include the following:
• Extension of home stereo system and computer audio - without wires.
• Listening aid for auditoriums, churches.
• Student-operated school radio station.
• College dorm favorite music broadcast service.
• Drive-ins, haunted hayrides, amusement parks, etc.
• Short-range, two-channel experiments and demonstrations.
We think you will be very pleased with the transmitting range, low noise,
audio quality, frequency stability and stereo channel separation of this build-
it-yourself synthesized FM stereo transmitter. If you follow our assembly
directions carefully and use your FM30 in accordance with applicable FCC
rules, a whole new world of sharing music, news and views with friends and
neighbors awaits you.
Since the sharing of music and information is vital to the culture of our 21st
century global community, we realized that our FM30 low-power Synthesized
FM Stereo Transmitter Kit was certain to attract worldwide interest among
hobbyists, students and "pioneers." While the use of the FM30 may need to
be limited to "wireless stereo extensions" in some USA households (to
comply with FCC Rules, Part 15), we have seen it serve very well as a
serious, though simple, broadcast station for remote villages throughout the
world where low cost AM-FM receivers are available to people of all
economic levels. After you're done building your kit, sitting back and listening
to your handiwork, consider this: many other small transmitters like the FM30
are faithfully relaying news and information to listeners in remote areas
around the world. The FM30 is most definitely not a toy!

FM30• 5
FM35 CIRCUIT DESCRIPTION
We will begin by talking about the new and improved power supply section of
the FM30. First off take a look at L1, C8, and C7. Does that look like anything
familiar? That is a low-pass filter designed to remove any RF from leaving the
power jack from the FM30, but more importantly from it entering back in! RF
can easily get into power regulators and other components and cause them
to “flake out” as we call it. The leads to hum and excessive noise in some
cases, and can be very hard to remedy without these filters.
D1 is designed to protect you in the unlikely event that power is connected in
reverse polarity. The diode is placed in-line with the power. Since a diode can
only conduct in one direction, it prevents a reversed power supply from
damaging your new FM30! We figured the addition of a 5 cent part was worth
the peace of mind. C5 is another part used to reduce RF interference.
C13 is used to “smooth” any ripple there may be on the input to VR1, a
12VDC low dropout regulator. You may ask “what does low dropout mean?”
No it doesn’t mean the regulator was made by a bunch of kids from a
privileged school, it means that it can regulate lower voltages than it’s non-
low dropout versions can. In this case to regulate to 12V, VR1 only needs
about 0.8V across it, this means it can regulate 12.8V and up!
C9 is used in conjunction with VR1 for good regulation of the +12V. The
+12V is then fed to VR2, a standard 5V regulator. This simply steps the +12V
down to +5V for our logic and audio circuits. At this point our voltages are
very well regulated for lowest noise! C10 works with VR2 for good regulation.
Now on to the audio input and control circuitry!
Audio is introduced into the FM30 at J8 (left) and J10 (right). For now we will
only talk about the left channel, as the right channel is a duplicate of the left.
Immediately after J8, you will notice L2 and C28. These parts are to prevent
EMI produced from transmitting from getting into your FM30 and messing up
the audio quality, similar to what we talked about in the power supply above.
After this filter the audio goes into U4:A, a simple rail to rail opamp. R46,
U2:A, and R43 set the gain of the opamp.
You may wonder, where the heck is U2:A? I don’t see any pots in my kit!
Well, U2:A is a digitally controlled pot. Inside of the IC are a bunch of
transistors switching in an out resistor arrays to make a digitally controlled
variable resistance. In turn, this variable resistance controls the gain of U4:A,
thus U2:A is the volume and balance control! We just happened to draw the
IC like a pot in the schematic software to make more sense.
After this gain stage, the audio moves on to U5:B, another opamp

FM30•6
surrounded by a bunch of resistors and capacitors. This arrangement of parts
is a low pass filter. This filter is designed to help reduce high-frequency audio
signals from mixing with the stereo pilot signal and producing mixing products
of various frequencies. Ok, perhaps that is too much to bite off. In layman's
terms, this low pass filter prevents high frequency audio signals like symbols
and chimes from getting garbled up during the creation of a stereo signal
before transmission, so it increases the audio quality of the final transmitted
signal.
This signal is then piped off to U3, the BH1415F stereo modulator IC. We
wont get into that quite yet, because we have another circuit of importance
before this that you will find to be very helpful to you during day to day use!
Take a look at D9, D10, and R39. These are peak detectors that sample both
the left and right channels and combine them together, which is presented on
pin 3 of U5:A. The levels that these diodes detect are then compared against
the constant voltage level seen on pin2 of U5:A. Right now R33 and R38 are
not used, but are there in case the threshold needs to be changed in future
revisions. Your product uses the 2.5V bias reference because it happened to
be the correct value to detect audio peaks. Notice I used the term compare;
U5:A is set up to be a comparator since it has no negative feedback.
Once the voltage on pin 3 surpasses that on pin 2 (our reference), the state of
the output pin 1 of U5:A goes high (5V). If the voltage on pin 3 goes below that
on pin 2, the output goes low (0V). The comparator is set up with these
specific diodes and voltage reference so that audio peaks surpassing a very
specific level flip the comparator state back and forth. This change of state is
then sent to the microcontroller U1, and the program in there counts how
many times this happens in an interval of time and then computes a quality of
signal value for you. In our case, the comparator is designed to detect peaks
over +/-75kHz of deviation, which is the standard bandwidth used by radio
stations. If you run the volume up too high on the FM30, the comparator
reference level is surpassed often, the micro counts this, and an indicator on
the display will show a poor quality of signal indication.
Speaking of the reference voltage, all of the analog circuitry needs to be
biased up at 1/2 of the supply voltage so that your audio signal has the
greatest possible dynamic range. We would like the analog signals to be able
to go all the way from 0V to 5V, and in order to do this with minimal distortion
we need 2.5V. This bias voltage is generated with a simple resistor divider
consisting of R22 and R24, and then noise filtered with C42 and C43. This
voltage is then “amplified” with U5:D which is set at a gain of 1 and then
distributed to the rest of the analog circuitry.
This leads us to the next important part of the circuit, the microcontroller. This
section is essentially the “brains” of the show. The microcontroller does
several things all of the time; it checks for button presses, it counts the quality

FM30• 7
of signal information, it measures RF power, and it updates the display. The
microcontroller also does important tasks like converting the frequency value
to text on the display that you can read, and signals that the stereo modulator
IC needs to go to that frequency. It also sends the proper signals to the level
control IC U7, which is just a digital to analog converter, U4, the digital pot,
and DS1, the LCD display. In all there is a lot going on inside of the
microcontroller, and be glad you don’t have to do things with a bunch of dip
switches any more.
Now here comes the fun part, the stereo modulator IC, U3. This IC is a great
little part, and contains a lot of circuitry that helps us get on the air with
minimal fuss, and great sound. This IC not only contains a stereo multiplexer,
but also a phase locked loop (PLL), audio filters, and equalizations.
The audio filter portion of the part adds a little more low-pass filtering to the
audio to increase quality more than what our external low pass filter does on
its own. The equalization portion enhances the high frequencies for the radio
standard of 75uS in the US. 75uS is just a term used for a high-pass filter to
enhance the high frequency audio before transmission to help reduce noise
upon reception.
The PLL is the portion of the IC which locks your chosen transmission
frequency to the crystal reference X1. The PLL portion also contains an
oscillator circuit which works in conjunction with the external parts of D5 and
the STUB (that weird trace on the back of the board). D5 is called a varactor
diode, and is a special variety of diode that is connected backwards. As a
reverse DC voltage is applied across the diode, its capacitance varies. The
higher the voltage, the less the capacitance. This is due to depletion layers of
the diode junction, but we wont get into details here. This variable capacitor in
conjunction with the stub, which is actually an inductor (coil) is the basis of our
voltage controlled oscillator! As the voltage increases across D5, the
frequency of oscillation increases.
The stub is just acting like a coil in this circuit, and because it is part of the
circuit board layout, it has a very predictable value. This prevents us from
having to tune anything in this section like our old products. Just turn the unit
on, and you are good to go! The best part of the stub is it’s low sensitivity to
microphonics. Microphonics is a term used for mechanical vibrations that are
picked up in a VCO circuit by vibrating components changing in value
because of mechanical shock. The sub value is very hard to alter from
mechanical shock, and therefore quite immune to vibration.
So what actually tunes the VCO you may ask? Good question. A PLL uses a
phase comparator to compare the crystal frequency with the oscillator
frequency combined with some internal dividers which are programmable. If
the frequency is too low, U3’s PLL tells pin 7 to turn up the voltage. This signal

FM30•8
on pin 7 needs to be filtered and amplified for good control, and that is
provided by Q2 and Q3, along with R18, R17, C34, R20, C38, R21, and C33.
All of these parts together act like a low pass filter to slow the tuning time
enough for our multiplex signal to still be transmitted, but the tuning signals to
not be transmitted. The parts in this section are carefully chosen for best
operation in audio performance, but have the drawback of being really slow to
tune from one end of the dial to the other. To speed it up would mean to loose
some of the low frequency response of our audio signal. In the case of the
FM30, we have made the PLL very slow to pass low frequency audio very well
for best quality. You will just have to be patient when you turn the unit on
before you can begin transmitting. Since most of these transmitters are left
running all the time on the same frequency, we knew this wouldn’t be a
problem for most of you.
Now there are some other tricks going on in the PLL and the VCO circuit
which you may wonder about. What is the purpose of Q4? Well, because we
are tuning a broad range of frequencies in the FM30, the VCO’s tuning
sensitivity vs. frequency can change quite a lot. Without this part a properly
adjusted +/-75kHz FM stereo signal at 108.1MHz may be +/-250kHz by the
time you get down to 88.1MHz! This is unacceptable, because it would be
very hard to know when you were over-modulating without test equipment.
This would also render the quality of signal detector useless that we have on
the audio inputs. Q4 corrects the tuning sensitivity by acting like a variable pot
based on the tuning voltage. As the tuning voltage goes down, Q4 is turned on
more and more, which in turn allows less and less of the multiplex signal that
is injected into the VCO from pin 5 of U3 to reach the VCO. It is a great little
compensation circuit which keeps our signal within +/-10kHz of error across
the band!
Now that we have our locked frequency and our multiplexed signal added to it
we want to get the level up to where we can transmit it! The level directly out
of U3 on pin 11 is small, just enough to cover a room, so we need to boost it a
little. U8 is a high-gain amplifier which will get up the level for us so the FM30
has a little more “oomph”. However we don’t want too much “oomph” where
we don’t need it, so before the final amp we have D8, which is another special
variety of diode called a pin diode. This diode has a neat way of working like a
variable RF resistor. As you put more and more current through it, more and
more RF will pass through it too. To vary the current through D8, we have U7,
which is a digital to analog converter. This will generate from 0-5 volts in 256
steps, and in doing so, will drive D8 with 256 steps of current control, which
gives us the ability to control output level quite a bit. L5 and C62 prevent RF
from getting back into the gain control of U7 and messing it up.
The higher level RF out of U8 is then sent through a low pass RF filter to
reduce harmonics, and finally to the output jack where you would connect an
antenna. L6 is simply to provide a DC path to ground in case of any static

FM30• 9
electricity or low frequency interference.
Whew, a lot to absorb here! Surprising how much great info can be gleaned
from a kit, isn’t it? We covered a lot of aspects of electronics here in one
simple project, digital, power, RF, and analog. If you want more information on
these subjects, there are a lot of great electronics books and websites out
there, and here are some keywords to search for: COMPARATOR,
VARACTOR DIODE, PIN DIODE, LOW PASS FILTER, DIGITAL POT, DAC
(Digital to Analog Converter), JFET (Q4), MULTIPLEX.
Have fun and happy learning! Now on to the kit building...
-Ramsey Staff.

FM30•10
RAMSEY Learn-As-You-Build KIT ASSEMBLY
There aren’t that many solder connections on the BL2 printed circuit board, but
you should still practice good soldering techniques.
• Use a 25-watt soldering pencil with a clean, sharp tip, preferably a
temperature regulated iron, but a standard 25W will do.
• Use only rosin-core solder intended for electronics use.
• Use bright lighting; a magnifying lamp or bench-style magnifier may be
helpful.
• Do your work in stages, taking breaks to check your work. Carefully
• brush away wire cuttings so they don't lodge between solder connec-
tions.
We have a two-fold "strategy" for the order of the following kit assembly steps.
First, we install parts in physical relationship to each other, so there's minimal
chance of inserting wires into wrong holes. Second, whenever possible, we in-
stall in an order that fits our "Learn-As-You Build" Kit building philosophy. This
entails describing the circuit that you are building instead of just blindly install-
ing components. We hope that this will not only make assembly of our kits eas-
ier, but help you to understand the circuit you’re constructing.
For each part, our word "Install" always means these steps:
1. Pick the correct part value to start with.
2. Insert it into the correct PC board location.
3. Orient it correctly, follow the PC board drawing and the written
directions for all parts - especially when there's a right way
and a wrong way to solder it in. (Diode bands, electrolytic
capacitor polarity, transistor shapes, dotted or notched ends
of IC's, and so forth.)
4. Solder all connections unless directed otherwise. Use enough heat
and solder flow for clean, shiny, completed connections.

FM30• 11
FM30 PARTS LAYOUT DIAGRAM

FM30•12
FM30 PARTS LIST
SEMICONDUCTORS
 1 LM940CS-12 12VDC low dropout regulator (VR1)
 1 1N4000 series power diode (can be any number from 1N4002 to
1N4007 (Black body, grey stripe, marked 1N4002) (D1)
 1 1N4148 Small signal switching diodes. (Marked 4148) (D3)
 3 SD101 Shottkey switching diodes (orange body, black stripe, marked
101A) (D9,10,11)
 2 2N3904 NPN transistors (marked 3904) (Q2,3)
 1 J177 P-Channel JFET in a TO-92 (marked J177) (Q4)
 1 78L05 5V regulator in a TO-92 package (marked LM78L05) (VR2)
 1 LMC6482AIN Dual rail to rail opamp. (U4)
 1 LMC6484AIN Quad rail to rail opamp. (U5)
 1 28-pin microcontroller IC with sticker (U1)
 1 MCP42010-I/P A dual 10k digital pot (U2)
 1 Small green LED (D4)
RESISTORS
 1 4.7 ohm resistor (yellow-violet-gold) (R35)
 2 100 ohm resistors (brown-black-brown) (R43,44)
 1 120 ohm 1/2 watt resistor (brown-red-brown) (R34)
 1 180 ohm resistor (brown-grey-brown) (R20)
 2 270 ohm resistor (red-violet-brown) (R6,9)
 4 1k ohm resistors (brown-black-red) (R10,16,27,36,37)
 2 2.2k ohm resistors (red-red-red) (R22,24)
 2 3.3k ohm resistor (orange-orange-red) (R21,31)
 1 4.7k ohm resistor (yellow-violet-red) (R17)
 6 10k ohm resistors (brown-black-orange) (R2,3,4,7,32,39)\
 2 16k ohm resistors (brown-blue-orange)(R45,46)
 1 20k ohm resistor (red-black-orange) (R18)
 2 27k ohm resistors (red-violet-orange) (R14,28)
 1 33k ohm resistor (orange-orange-orange) (R29)
 4 47k ohm resistors (yellow-violet-orange) (R23,25,)
 4 56k ohm resistors (green-blue-orange) (R15,19,26,30)
 1 10k ohm trim pot for display contrast. (Orange top, marked 103) (R1)
CAPACITORS
 5 1nF or 0.001uF ceramic disc capacitors (marked 102) (C5,33,46,68,69)
 9 10nF or 0.01uF ceramic disc capacitors (marked 103)
(C3,4,7,8,12,32,49,53,55)
 10 0.1uF ceramic disc capacitors (marked 104)
(C6,14,17,24,36,37,43,48,57,62)
 1 10pF ceramic disc capacitor (marked 10) (C2)
 2 33pF ceramic disc capacitors (marked 33) (C22,26)

FM30• 13
 1 47nF or 0.047uF ceramic disc capacitor (marked 473) (C34)
 2 47pF ceramic disc capacitors (marked 47) (C67,70)
 1 75pF ceramic disc capacitor (marked 75) (C66)
 5 100pF ceramic disc capacitors (marked 101) (C16,25,28,44,50)
 2 150pF ceramic disc capacitors (marked 151) (C31,40)
 2 560pF ceramic disc capacitors (marked 561) (C23,45)
 2 3300pF ceramic disc capacitors (marked 332) (C30,39)
 3 100uF electrolytic capacitors (C13,38, R5[no kidding!])
 1210uF electrolytic capacitors (C1,9,10,11,15,21,27,29,41,42,47,51)
MISCELLANEOUS
 1 28 pin socket (for U1)
 1 PCB Mounted BNC connector (J9)
 1 2x8 line LCD display (DS1)
 1 14-pin dual row connector (for DS1)
 1 DPDT Power switch (S1)
 6 2.2uH inductors (green body, red-red-gold-silver) (L1,2,3,4,5,6)
 2 4 turn air core inductors (L8,9)
 1 2.1mm center post positive power jack (J3)
 2 RCA audio jacks (J8,J10)
 2 8-pin dual row connectors (J2,5)
 1 Mini speaker (SP1)
 3 Momentary buttons (S2,3,4)
 1 7.6MHz Crystal (Marked 7.600) (X1)
 1 Switch cap
 Case Top & Bottom, screws for case
 Front and rear panels
 1 15VDC power supply
 1 Whip antenna
SURFACE MOUNT PARTS, PREINSTALLED
 1 BBY40 Varactor diode. SOT23 package (marked S2) (D5)
 1 1SV172 Pin Diode. SOT package. (Strange B and E marking) (D8)
 2 0.1uF ceramic surface mount capacitors (C18,35)
 2 470pF ceramic surface mount capacitors (C19,20)
 1 BH1415F Stereo Modulator IC (U3)
 2 10K ohm surface mount resistors (marked 103) (R12,13)
 1 TC1320EOA Digital to analog converter (U7)
 1 GAL5 DC-8GHz monolithic RF amplifier (U8) Marked o5

FM30•14
FM30 PC BOARD ASSEMBLY STEPS
The FM30 is one of our larger, more complicated kits, however, if you follow
the steps closely you will find that it will go together smoothly. We will start
with the larger main PC board. We’ll have a working kit in no time!
 1. The first thing you’ll have to do is to separate the front panel PC board
from the main PC board. Simply grasp the two boards and carefully snap
them apart.
 2. Once you have the boards apart you’ll notice that there are little tabs
left where the boards used to be connected. You’ll want to trim these
down so that the board fits into the case correctly. Take your sidecutters
and nip off the excess board material, then take some sandpaper or bor-
row your wife’s emery board to sand down what’s left. But don’t tell your
wife that we told you to borrow the emery board!!
 3. Now we’ll install a surface mount part but don’t worry, it’s not a difficult
one. We’ve placed all the tough ones on the board for you and left you the
regulator VR1, LM940CS-12 12VDC low dropout regulator. The first thing
to do is to tin the large pad that the body of the regulator will sit on. Tin-
ning means to melt a small amount of solder on that pad. Next, place the
part on the large pad so that the legs line up with their individual, smaller
pads. Once you’re sure everything is aligned properly, solder the three
leads of the part. With those soldered, you’re going to solder the large
metal tab on the part to the pad you tinned earlier. Hold your iron down on
the large metal tab on the regulator while pressing it onto the tinned pad
until you see the solder flow. That should hold things in place and should
also provide a heatsink for the part.
 4. Install U5, the LMC6484AIN quad rail to rail opamp. We’re starting
with the ICs so that you can use the PC board to keep the part flat until
you solder it. Follow the dot or notch on the chip and match it to the silk-
screen marking or Parts Layout Diagram for proper placement. Make sure
that all the pins are through the board and none are bent under or sticking
out, then slightly bend two corner pins to keep the IC from falling out when
you flip the board over. Check to be sure that the part is flat to the PC
board, then solder all 14 pins.
 5. Install U2, an MCP42010-I/P dual 10K digital pot. Follow the notched
end for correct placement and make sure you solder all the pins.
 6. Install U4, the LM6482 dual rail to rail opamp, following the same pro-
cedure as the last two ICs.
 7. Install the socket for U1, the 28 pin microcontroller IC. Install the
socket the same way you installed the ICs in the above steps, making

FM30• 15
sure the part is flush to the PC board before soldering and placing the
notched end as shown on the Parts Layout Diagram and PC board silk-
screen.
 8. You can now place the microcontroller in the socket you just installed.
Be sure the notched end is placed correctly and press the chip into the
socket, then check for bent under or bent out pins.
Now we’ll start installing the rest of the components starting at the corner of
the board near J3. Place the board so that you can read the writing on it right-
side up.
 9. Install C8, 10nF or 0.01uF ceramic disc capacitor (marked 103). Disc
caps have no polarity and can be installed in either direction. We’ll always
let you know when you have to be particular about how to install a compo-
nent.
 10. Install C5, 1nF or 0.001uF ceramic disc capacitor (marked 102).
 11. Install D1, a 1N4000 series diode (1N4002—1N4007). Note the stripe
or band on one end of the part and the stripe marked on the PC board
silkscreen and Parts Layout Diagram. This diode must be placed correctly
to function properly. Line the part up with the mark on the board and sol-
der it in place.
 12. Install L1, 2.2uH inductor (green body, red-red-gold-silver).
 13. Install C7, 10nF or 0.01uF ceramic disc capacitor (marked 103).
 14. Install C50, 100pF ceramic disc capacitor (marked 101).
 15. Install L3, 2.2uH inductor (green body, red-red-gold-silver).
 16. Install R45, 16k ohm resistor (brown-blue-orange).
 17. Install C51, 10uF electrolytic capacitor. Electrolytic caps have a polar-
ity and must be installed correctly in order to work . . . and in some cases
in order not to blow up when power is applied! You’ll note that the legs of
the part are different lengths and there is a stripe or band down one side
of the capacitor that corresponds to the shorter of the two leads. This is
the negative side of the cap. The silkscreen and Parts Layout Diagram will
show where the positive lead is to be placed by a “+” sign on the board.
Orient the part with the longer lead in the “+” hole and solder the part in.
 18. Install R44, 100 ohms (brown-black-brown).
 19. Install R30, 56k ohms (green-blue-orange).
 20. Install C13, 100uF electrolytic capacitor. Remember to orient the
longer positive lead with the ’+’ sign on the board before soldering.

FM30•16
 21. Install C44, 100pF (marked 101).
 22. Install R24, 2.2k ohms (red-red-red). This resistor is installed in
standup fashion; simply place one lead of the part into the hole marked
with a circle then bend the other lead over to fit in the other hole for R24.
Solder as usual.
 23. Install C45, 560pF disc capacitor (marked 561).
 24. Install R26, 56k ohm resistor (green-blue-orange).
 25. Install R28, 27k ohms (red-violet-orange).
 26. Install D10, SD101 Shottkey diode (marked SD101A). Follow the
band on the PC board and the band on the diode for orientation.
 27. Install R27, 1k ohm resistor (brown-black-red).
 28. Install C43, 0.1uF ceramic disc capacitor (marked 104).
 29. Install C42, 10uF electrolytic capacitor. Remember to watch the polar-
ity when installing.
 30. Install R22, 2.2k ohms (red-red-red).
 31. Install C47, 10uF electrolytic. Do I have to remind you about the polar-
ity again? No, I didn’t think so.
 32. Install C17, 0.1uF ceramic disc capacitor (marked 104).
 33. Install C49, 10nF or 0.01uF ceramic disc capacitor (marked 103).
 34. Install C57, 0.1uF ceramic disc capacitor (marked 104).
 35. Install C9, 10uF electrolytic cap. Remember polarity!
 36. Install VR2, 78L05 (marked LM78L05). Bend the center lead out and
place the flat side as shown on the silkscreen. Solder all three leads.
 37. Install C53, 10nF or 0.01uF ceramic disc capacitor (marked 103).
 38. Install C10, 10uF electrolytic cap. Check placement before soldering.
 39. Install C1, 10uF electrolytic capacitors, below and to the right of C10.
It’s another electrolytic but you’re an old pro at these by now so I won’t
remind you to be sure to line up the longer lead with the hole marked “+”.
 40. Install R2, 10k ohm resistor (brown-black-orange).
 41. Install C2, the only 10pF capacitor (marked 10).
 42. Install C14, 0.1uF ceramic disc capacitor (marked 104).

FM30• 17
Well, we’ve made some good progress so far and your board is starting to
have a few parts on it. Take a break if you need to and we’ll start again in the
area right below J8, assuming you’re orienting the board so that you can read
the silkscreen and it isn’t upside down. I’ll go warm up my forgotten coffee and
be right back.
Ok, break’s over. Let’s keep going.
 43. Install L2, 2.2uH inductor (green body with red-red-gold-silver bands).
 44. Install C28, 100pF ceramic disc capacitor (marked 101).
 45. Install C29, yet another 10uF electrolytic cap. Orientation!
 46. Install R46, 16k ohm resistor (brown-blue-orange).
 47. Install R43, 100 ohms (brown-black-brown).
 48. Install R19, 56k ohms (green-blue-orange).
 49. Install C25, 100pF ceramic disc capacitor (marked 101).
 50. Install C23, 560pF disc capacitor (marked 561).
 51. Install R15, the last 56k ohm resistor (green-blue-orange).
 52. Install R14, 27k ohm resistor (red-violet-orange).
 53. No part is installed in the R33 position; this part was left in place in
case we need it in the future.
 54. As with R33 above, install nothing in the space set aside for R38.
 55. Install C36, 0.1uF ceramic disc capacitor (marked 104).
 56. Install D9, another SD101 Shottkey diode (marked SD101A). Again,
follow the silkscreen and banded end of the part for correct placement.
 57. Install R16, 1k ohm resistor (brown-black-red).
 58. Install C27, a 10uF electrolytic capacitor. Remember that the long
lead should be placed in the hole marked with the “+” sign.
 59. Install C32, 10nF or 0.01uF ceramic disc capacitor (marked 103).
 60. Install R39, 10k ohm resistor (brown-black-orange).
 61. Install C37, 0.1uF ceramic disc capacitor (marked 104).
 62. Install C39, 3300pF ceramic disc capacitor (marked 332).
 63. Install C40, 150pF ceramic disc capacitor (marked 151).

FM30•18
 64. Note the silkscreen position for C52. This part is not installed; leave
the space for C52 empty.
 65. Install C26, 33pF ceramic disc capacitor (marked 33).
 66. Install C22, the other 33pF ceramic disc capacitor.
 67. Install X1, the 7.6MHz crystal (marked 7.600). Place the leads in the
holes then bend the part over so that it fits in the silkscreen outline. Solder
both leads.
 68. Install R32, 10k ohms (brown-black-orange).
 69. Install C62, 0.1uF ceramic disc capacitor (marked 104).
 70. Install L4, 2.2uH inductor (green body with red-red-gold-silver bands).
 71. Install C11, 10uF electrolytic capacitor. Again, be careful to follow the
silkscreen when installing.
 72. Install L5, 2.2uH inductor (green body with red-red-gold-silver bands).
 73. Install C55, 10nF or 0.01uF ceramic disc capacitor (marked 103).
 74. Let’s move toward the back of the board, near J9, and install L6,
2.2uH inductor (green body with red-red-gold-silver bands).
 75. Install C67, 47pF ceramic disc capacitor (marked 47).
 76. Install L9, 4 turn air coil.
 77. Install C66, 75pF ceramic disc capacitor (marked 75).
 78. Install L8, the other 4 turn air coil.
 79. Install C70, 47pF ceramic disc capacitor (marked 47).
The caps and coils you just installed are the output filter for the kit.
 80. Install C69, 1nF or 0.001uF ceramic disc capacitor (marked 102).
 81. Install R34, 120 ohm 1/2 watt resistor (brown-red-brown). This part is
easy to recognize because it’s larger than the other resistors.
 82. Install C21, 10uF electrolytic cap. Yes, watch your polarity.
 83. Install C46, 1nF or 0.001uF ceramic disc capacitor (marked 102).
 84. Install R35, 4.7 ohms (yellow-violet-gold).
 85. Install C68, 1nF or 0.001uF ceramic disc capacitor (marked 102).

FM30• 19
 86. Install R36, 1k ohms (brown-black-red).
 87. Install R37, 1k ohms (brown-black-red).
 88. Install C41, 10uF electrolytic. Remember that polarity is still important!
 89. Install C3, 10nF or 0.01uF ceramic disc capacitor (marked 103).
 90. Install C30, 3300pF (marked 332).
 91. Install C31, 150pF (marked 151).
 92. Install R18, 20k ohms (red-black-orange).
 93. Install C16, 100pF capacitor (marked 101).
 94. Install R25, 47k ohms (yellow-violet-orange).
 95. Install C48, 0.1uF ceramic disc capacitor (marked 104).
 96. Install D11, SD101 Shottkey diode (marked SD101A). Follow the
band on the PC board and the band on the diode for orientation.
 97. Install R9, 270 ohms (red-violet-brown).
 98. Install D3, 1N4148 small signal switching diode. This part has a
banded end that must be lined up with the band on the silkscreen and
Parts Layout Diagram.
 99. Install SP1, the mini speaker. You’ll see a “+” sign on one side of the
part and the same “+” sign on the board. Line these two up and solder the
part.
 100. Install R31, 3.3k ohms (orange-orange-red).
 101. Install Q4, a J177 P-Channel JFET in a TO-92 package. Notice the
flat side on the part and the flat side shown on the PC board. Line the part
up with the flat side and bend the center lead out so that the part fits in the
board correctly. Push it down but not to the point of stressing the leads,
then solder all three leads in place.
 102. Install a wire jumper in the spot designated for D2. Simply bend a
scrap component lead into the shape of a staple and solder it where the
board is marked for D2. Nope, there’s no polarity with a piece of wire! This
part was replaced by a jumper to improve the operation of your FM30.
 103. Install another wire jumper in the D6 position. Just like D2 before,
this part was removed and we need to put a jumper in its place.
 104. Install R10, 1k ohms, (brown-black-red).

FM30•20
FM30 SCHEMATIC CENTERFOLD