Ramsey Electronics FM100B Instruction Manual Download | Manualshive

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FM100B

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1

Ramsey Electronics Model No. FM100B

Here’s the ultimate radio transmitter for all of you home brew
DJs out there! This all-in-one stereo transmitter has all the
features you will ever need for transmitting a school radio
station, around your yard, or even around the block.
Use the optional high power configuration for extra boost
when transmitting outside of the US!

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2 Line inputs and one mic input-plus a built in mixer!

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New Line output for monitoring your show!

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PLL Crystal controlled for rock solid frequency

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Left and right channel peak hold indicators and large LED frequency
display

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Built in power supply, just plug it in! Now operates from 85-264VAC (47 - 63
Hz) without jumpers!

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25 mW output standard, optional 1W configuration for operation outside
the US!

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Auto AGC microphone muting function for cool talk-overs

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Rugged steel enclosure for years of service

POWER

AUDIO

LEVEL

(L)

(R)

PROF

ESSI

ONA

L

FM S

TEREO

TRAN

SMIT

TER

Model FM100B

SELF

TEST

SETUP

FREQ

UP

FREQ

DOWN

MIC

AUTO

AGC

LINE 1

LINE 2

MIC

MIC

INPUT

MIC ON

FREQ LOCK

-18

-15

-12

-9

-6

-3

0

+3

+6

+9

-18

-15

-12

-9

-6

-3

0

+3

+6

+9

FREQUENCY

1
2
3
...
»

Summary of Contents for FM100B

Page 1: ...tput for monitoring your show PLL Crystal controlled for rock solid frequency Left and right channel peak hold indicators and large LED frequency display Built in power supply just plug it in Now operates from 85 264VAC 47 63 Hz without jumpers 25 mW output standard optional 1W configuration for operation outside the US Auto AGC microphone muting function for cool talk overs Rugged steel enclosure...

Page 2: ...Meter RAMSEY AMATEUR RADIO KITS DDF1 Doppler Direction Finder HR Series HF All Mode Receivers QRP Series HF CW Transmitters CW7 CW Keyer CPO3 Code Practice Oscillator 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 FM100B PROFESSIONAL STEREO TRANSMITTER INS...

Page 3: ...INC 590 Fishers Station Drive Victor New York 14564 Phone 585 924 4560 Fax 585 924 4555 www ramseykits com TABLE OF CONTENTS Introduction 4 Circuit Operation 5 Parts List 13 Assembly 16 Section Layout 17 Display Layout 18 Display Schematic 27 Main Board Layout 35 Rear Panel Wiring Pictures 43 Testing and Calibration 49 Troubleshooting 51 Warranty 55 ...

Page 4: ... comments here is the result of months of design and years of stereo transmitter experience The FM100B has all of the features needed to run a professional sounding radio station It includes extensive audio filtering to prevent high frequency audio interference AGC Automatic Gain Control with the microphone to prevent overloading distortion a frequency display with easy frequency adjustment 2 line...

Page 5: ...uction of noise in our final transmission We needed a display that produced as little noise as possible but was also easy to read LED displays provide the best choice for visibility but we couldn t use normal display drivers that are multiplexed Multiplexing means that all of the digits are never on at the same time Each one is turned on in turn at a high enough rate so that to your eye it looks a...

Page 6: ...oss diode D1 the main varactor diode in our oscillator circuit As the voltage across the varactor increases it causes a decrease in capacitance Increasing reverse bias essentially increases the distance between the capacitor s plates by increasing the depletion region in the diode C kA d The decrease in capacitance causes an increase in U2 s RF oscillator fo 1 2 π LC bringing the FM100B s output f...

Page 7: ... full output It also provides plenty of level for some further amplification with the export model FM100BEX Because our amplifier is not truly linear it introduces some harmonics Harmonics are multiples of the primary frequency The primary one we are trying to get rid of is the second harmonic F x 2 which in our case winds up in the aircraft band It is extremely important for us not to interfere w...

Page 8: ...gh U13 set up as a level detector mutes the audio coming in by turning on Q7 and Q8 We will get back to the microphone circuit in a minute If the AGC circuit is off audio continues to U5 D another summing amplifier This stage sums the audio from the microphone circuit and the audio from our current line input signal together The level of microphone audio mixed in is controlled by R16 Notice that t...

Page 9: ...amplifier U12 is a microphone conditioner IC It has a feature that we use in the FM100B that really help us out by eliminating a lot of manual work This is the AGC or Automatic Gain Control This prevents us from overloading the audio circuitry when we get excited and yell into the microphone When the amplitude of the signal coming from the microphone increases the gain of the microphone amp decrea...

Page 10: ...nd your frequency may be changed 1 A user presses the FREQ UP button 2 The microcontroller stops scanning the LD Lock Detect line and sees what key the user has pressed 3 It s a Frequency key Is the unit in setup mode 4 Yes Increase the frequency value in RAM by 100 KHz 5 Send the appropriate divide by N to U2 along with the rest of the required data 6 Decode the display digits and update the disp...

Page 11: ...g heating both wires and pads simultaneously Apply the solder on the iron and the pad when the pad is hot enough to melt the solder The finished joint should look like a drop of water on paper somewhat soaked in Mount all electrical parts on the top side of the board provided The top side is clearly marked with the word TOP you can t miss it This is the side that has little or no traces on it but ...

Page 12: ... to the board Keep the portion of the resistor closest to the board mounted right on the board For each part our word Install always means these steps FM100B ASSEMBLY 1 Pick the correct part value to start with 2 Insert it into the correct PC board location Make sure the part is mounted flush to the PC board unless otherwise noted 3 Orient it correctly Follow the PC board drawing and the written d...

Page 13: ...istors brown black red R15 17 20 34 38 53 62 80 88 96 97 5 4 7K ohm resistors yellow violet red R22 28 33 39 41 25 10K ohm resistors brown black orange R1 2 3 4 7 9 13 19 27 35 48 49 52 54 57 59 67 70 78 79 81 84 85 94 111 2 18K ohm resistors brown gray orange R63 89 7 22K ohm resistors red red orange R5 21 43 51 69 73 98 1 27K ohm resistor red violet orange R112 2 12K ohm resistor brown red orang...

Page 14: ...pacitors marked 56 C55 74 4 68 pF capacitors marked 68 C47 57 70 76 2 82 pF capacitors marked 82 C56 75 2 180 pF capacitors marked 181 C62 80 2 680 pF capacitors marked 681 C54 73 2 0 0022 uF capacitors marked 222 C60 78 Electrolytic capacitors 1 1 uF electrolytic capacitor C20 29 10 uF electrolytic capacitors C1 2 3 14 15 18 19 22 25 29 35 39 40 48 51 52 53 58 69 71 72 77 81 82 83 85 87 110 113 1...

Page 15: ...ch caps 3 Set screw knobs 1 Bottom case half with pre attached membrane panel 1 Top case half 17 4 40x1 4 board mounting screws 4 4 40x5 8 standoffs 6 6 32x1 4 self tapping black case screws 2 4 40x1 2 self tapping black machine screws 1 Fuse holder with hardware 1 1 Amp fuse 1 110 Volt line cord with plug and pre installed Molex pins 1 Line cord grommet black plastic MP5P4 1 Antenna grommet black...

Page 16: ...ls before we continue with the more crowded sections of the board Following is a list of all the sections in the manual that we will be going into A Display Board 19 B Microphone Amp 22 C Audio Mixer 24 D Low Pass Audio Filters 26 E Peak Hold Meters 30 F Transmitter 32 G Transmitter Amplifier 36 H Microcontroller 38 I Power Supply 40 J Jacks and Switches 42 K Rear panel wiring 45 L PCB Mounting 48...

Page 17: ...FM100B 17 SECTION LAYOUT ON MAIN BOARD B C D1 D2 H E G F I ...

Page 18: ...FM100B 18 DISPLAY BOARD PARTS LAYOUT DIAGRAM Parts Layout Note Light Gray components are mounted on the reverse side of the board Rev 1 4 ...

Page 19: ...n from doing odd things like oscillating by itself 3A Install C86 another 0 01 uF ceramic capacitor marked 103 4A Install R96 a 1K ohm resistor brown black red 5A Install R97 another 1K ohm resistor brown black red 6A Install U9 one of the LM3915 Semi log bargraph driver ICs Make absolutely sure before soldering that you have installed all 18 pins into the appropriate holes Verify that the notch o...

Page 20: ...be lining up with holes in the front panel Once the height is set bend the leads to hold the LED in place then solder Note Some builders prefer to temporarily install the front panel on the case and line up D7 and D8 flush with the front panel overlay This increases the viewing angle of the indicator when it is tight to the display 14A Install D8 in the same fashion making sure it is at the same h...

Page 21: ...e capacitor while the positive side is marked on the parts layout If you fail to mount this component correctly the part can fail as well as prevent proper operation of your project We will be installing many more of these later in the project so be sure and remember this 19A Install C85 another 10 uF electrolytic capacitor on the rear side of the front panel Watch that orientation again Great job...

Page 22: ...r yellow violet orange 8B Install R111 a 10K ohm resistor brown black orange 9B Install C114 a 0 001 uF ceramic capacitor marked 102 10B Install R35 a 10K ohm resistor brown black orange 11B Install R20 a 1K ohm resistor brown black red 12B Install R38 a 1K ohm resistor brown black red 13B Install R30 a 47K ohm resistor yellow violet orange This resistor sets the restore time for the soft switch w...

Page 23: ...arked with the positive sign on the PC board 20B Install C113 10 uF electrolytic capacitor Remember to watch the polarity 21B Install C19 a 10 uF electrolytic capacitor Polarity 22B Install C40 a 10 uF electrolytic capacitor 23B Install C22 a 10 uF electrolytic capacitor 24B Install C25 a 10 uF electrolytic capacitor 25B Install C14 a 10 uF electrolytic capacitor 26B Install C112 a 22uF electrolyt...

Page 24: ...orange 3C Install R79 a 10K ohm resistor brown black orange 4C Install R80 a 1K ohm resistor brown black red 5C Install R70 a 10K ohm resistor brown black orange 6C Install R69 a 22K ohm resistor red red orange 7C Install R48 a 10K ohm resistor brown black orange 8C Install R51 a 22K ohm resistor red red orange 9C Install R53 a 1K ohm resistor brown black red 10C Install R52 a 10K ohm resistor bro...

Page 25: ...on is enabled 20C Install R90 a 47K ohm resistor yellow violet orange R90 sets the recovery time for the audio to resume after an Auto AGC function If you wish to customize the recovery time lower this value to speed it up or raise it to slow it down It is located way over on the right hand side of the board It s time to take an eyeball break before we move on to the next section of our project No...

Page 26: ...k yellow gold 4D Install R81 a 10K ohm 5 resistor brown black orange gold 5D Install R77 an 82 5K ohm 1 resistor gray red green red brown 6D Install R89 an 18K ohm 5 resistor brown gray orange gold 7D Install R84 a 10K ohm 5 resistor brown black orange gold 8D Install R82 a 10 0K ohm 1 resistor brown black black red brown 9D Install R93 a 3 32K ohm 1 resistor orange orange red brown brown 10D Inst...

Page 27: ...FM100B 27 DISPLAY SCHEMATIC ...

Page 28: ... U8 one of the LF347N quad opamps This IC handles the filtering for the Left channel audio with these surrounding parts Make sure all 14 pins are through the board before soldering It s easy to accidentally fold over a pin while installing it 26D Install R46 an 82 5K ohm 1 resistor gray red green red brown 27D Install R68 a 100K ohm 5 resistor brown black yellow gold 28D Install R54 a 10K ohm 5 re...

Page 29: ... marked 181 48D Install C55 a 56 pF 5 ceramic capacitor marked 56 49D Install U4 another LF347N opamp This opamp and the surrounding parts handles the Right channel audio filtering Check all 14 pins before soldering 50D Install C52 a 10 uF electrolytic capacitor Check orientation before soldering as these are polarity sensitive 51D Install C48 another 10 uF electrolytic capacitor 52D Install C72 y...

Page 30: ...ith the stripe on the same end as shown in the Parts Layout Diagram This diode and its surrounding circuitry rectifies the audio signal into a DC level Capacitor C81 then holds this level for a long duration The resistance of R91 then determines how long C81 holds its charge the less the value the less time C81 holds the charge This is seen on the bargraph meters when you have a single pulse like ...

Page 31: ...itor 12E Install C58 another 10 uF electrolytic remember to check polarities 13E Install C71 a 10 uF electrolytic capacitor 14E Install C77 the last 10 uF electrolytic capacitor in this section Well that s it for the peak hold circuits and the 15 KHz low pass filter Quick and painless wasn t it We have to go back now and check all our work to make sure that we didn t install anything in the wrong ...

Page 32: ...ld have no trouble at all 1F Install R33 a 4 7K ohm resistor yellow violet red 2F Install R28 a 4 7K ohm resistor yellow violet red 3F Install R41 a 4 7K ohm resistor yellow violet red 4F Install R39 a 4 7K ohm resistor yellow violet red 5F Install C29 a 10 uF electrolytic capacitor orientation don t forget 6F Install C35 a 10 uF electrolytic capacitor 7F Install C21 a 33 pF ceramic disk capacitor...

Page 33: ...rly Note the flat side in the opposite direc tion from Q3 22F Install R37 a 47K ohm resistor yellow violet orange 23F Install R40 a 47K ohm resistor yellow violet orange 24F Install C42 a 0 1 uF ceramic capacitor marked 104 25F Install R26 a 100 ohm stand up resistor brown black brown 26F Install R22 a 4 7K ohm resistor yellow violet red 27F Install R7 a 10K ohm resistor brown black orange 28F Ins...

Page 34: ... VCO and therefore your whole kit 45F Install R36 a 1K ohm trimmer potentiometer The top is orange and marked 102 This pot is used to adjust your RF level to minimum require ments to prevent interference 46F Install C43 a 0 001 uF ceramic capacitor marked 102 47F Install L1 the large metal can inductor with the tunable slug Make sure the pins are through the holes before soldering into place Whew ...

Page 35: ...FM100B 35 MAIN BOARD PARTS LAYOUT ...

Page 36: ...100 ohm resistor brown black brown 5G Install C89 2 2 pF marked 2 2 6G Install C49 a 0 01 uF ceramic capacitor marked 103 7G Install R58 a 120 ohm large 1 Watt resistor brown red brown This resistor will run a bit hot but don t worry this is normal and well within the ratings of the component Place the component in the holes in a stand up fashion to increase the part s heat dissipation abilities T...

Page 37: ...ose attention to the orientation of this large capacitor it must be installed correctly 22G Install L8 13 turn air core inductor 23G Install the whip antenna with the provided screw Std version only 24G Solder the whip antenna screw in place on the bottom side of the board This may take a bit of time due to the heat that must be transferred from your soldering iron to the large metal area you are ...

Page 38: ...require or operate with these three parts installed so leave these positions open 1H Install C17 a 0 1 uF ceramic capacitor marked 104 2H Install R5 a 22K ohm resistor red red orange 3H Install C4 a 10 pF ceramic capacitor marked 10 4H Install C12 a 0 001 uF ceramic capacitor marked 102 5H Install C5 a 0 01 uF ceramic capacitor marked 103 6H Install R17 a 1K ohm stand up resistor brown black red 7...

Page 39: ...ame position as shown on the Parts Layout Diagram to prevent confusion later 17H Install U1 the IC with the sticker labeled FM100B into the socket Find the dot or notch on one end of the chip and orient it as shown in the Parts Layout Diagram If your chip has a large 1 on one end signifying pin 1 this end is oriented as though it were a notch It should be placed at the end of the socket closest to...

Page 40: ...your switches that they are pressed firmly to the board so that they will align properly in the case holes when completed 3I Install S2 the FREQUENCY UP switch 4I Install S3 the FREQUENCY DOWN switch 5I Install S4 the MIC IN switch 6I Install S5 the AUTO AGC switch 7I Install R42 one of the dual 10K ohm potentiometers Install this part so that its shaft is perfectly parallel to the PC board before...

Page 41: ... with the most picky eye that you possess right or left eye it s up to you We have installed quite a few parts up to this point and chances are you may have made a mistake somewhere along the line Even the best kit assemblers are known to make mistakes when putting their kits together Avoid simple mistakes like a solder bridge or a part installed backwards whoops by just simply looking over the bo...

Page 42: ...nd a lock nut to hold down the regulator flush to the board as shown Take a moment to check the components you just installed especially their orientation The next step is to mount the power supply to the main board before the final wiring of the unit takes place Please note that the switching power supply contains high voltages The large capacitor on the board is charged with rectified line volta...

Page 43: ...eference to the main board 7J Use the pre made 4 pin to 4 pin Molex wire jumper to connect between the power output on PS1 to the connector on the main board J3 Do not twist the cable the wires should be a one to one match The locking headers should snap them into place 8J Use the pre made 3 pin to 3 pin Molex wire jumper note that only two wires are used to go between J1 and the AC IN jack of the...

Page 44: ...FM100B 44 REAR PANEL WIRING PICTURES AC Input and RF Output Fuse Wiring Close up ...

Page 45: ...10VAC line cord has three wires black white and green The black wire does not have a factory installed Molex pin on it this is the HOT side of the power connection Strip and tin the end of the black wire 5K Locate the female Molex connector and insert the white line cord wire as shown above into the header jack Notice there is a small catch tab on one side of the pin Insert the pin into the Molex ...

Page 46: ...tinned in step 4L into a quarter loop so that it holds to the other tab of the fuse holder Solder this wire in place 11K Wrap the exposed solder tabs of the fuse holder with electrical tape to avoid accidentally touching the Live wires while you tune your transmitter 12K Make sure the 1 Amp fuse is installed in the fuse holder 13K Locate the chassis mount BNC connector Mount it to the rear panel u...

Page 47: ...m and pictures Also make sure that the two high voltage connections are to either side of the Molex plug and not in the center The green wire of the line cord is Earth ground not a high voltage connector It can be connected to either of the center pins of J2 Be very careful around these connections When we plug it in they will always be live Especially be careful of the power switch S1 The top pin...

Page 48: ...on of the connectors by looking at the mark you made previously indicating pin one 3L Using the other pre made 5 wire jumper cable connect from J8 to J10 Again make sure that pin 1 of J8 is connected to pin 1 of J10 J10 pin 1 is the top pin closest to R96 4L Connect the 4 pin Molex connector from the rear panel to J2 on the main board You can then set the cover in place without having to screw it ...

Page 49: ... or FREQ DN until the display shows 108 0 MHz if it does not already 6M Press both frequency buttons again and hold until you hear the triple beep confirmation This means the settings have been saved in Flash 7M Press both the auto AGC and the Microphone buttons Your display should now show the voltage of the PLL s voltage controlled oscillator 8M Using the included plastic tuning tool adjust L1 u...

Page 50: ...crank up the microphone gain 18M Press the MIC button and verify that the MIC LED turns on 19M Talk into the microphone you should hear sound from the receiver and the LED meters should indicate sound in both channels 20M Connect your audio source to either input RCA Line 1 or Line 2 jacks 21M Play some tunes through the unit and make sure the controls on the front are working for each channel res...

Page 51: ...TION Check your fuse If it is blown you will want to check section K for rear panel wiring or section J for the power supply Use a volt meter to check your power supply voltages Verify that there is 12 and 12 volts on the out put of the power supply and 5V on the output of VR1 Also check U1 pin 3 for a 4 MHz 1 MHz clock signal with an oscilloscope or frequency counter PROBLEM Everything works but ...

Page 52: ...can find the beads in com puter accessory magazines and electronic magazines You may be also over loading your receiver Try moving the transmitter and receiver further apart or turn R3 CCW to decrease your output power PROBLEM The unit doesn t store last frequency SOLUTION Don t forget to get out of setup mode by pressing both frequency buttons to set the frequency before shutting off the power PR...

Page 53: ...uch be assured that the 1K ohm resistors are actually the missing 10 K parts Hum m m I guess the red band really does look orange Ramsey Electronics project kits are packed with pride in the USA If you believe we packed an incorrect part or omitted a part clearly indicated in your assembly manual as supplied with the basic kit by Ramsey please write or call us with information on the part you need...

Page 54: ...FM100B 54 ...

Page 55: ...FM100B 55 ...

Page 56: ... Soldering Iron Ramsey WLC100 Thin Rosin Core Solder Ramsey RTS12 Needle Nose Pliers Ramsey RTS05 Small Diagonal Cutters Ramsey RTS04 OR Complete Soldering Tool Set RS64 2801 ADDITIONAL SUGGESTED ITEMS Optivisor Magnifier Headband Ramsey OPMAG Helping Hands Holder for PC Board Parts Ramsey HH3 Desoldering Braid Ramsey RTS08 RAMSEY ELECTRONICS INC 590 Fishers Station Drive Victor New York 14564 Pho...

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