Below are before and after pictures of the chassis of my Viking Messenger 1 CB Radio. I think you'll agree that my rebuild was a complete success!
About the Viking Messenger 1
The Viking Messenger 1 is a radio transceiver, designed by the EF Johnson company, for two-way radio service in the 27Mhz Citizens band. This transceiver was manufactured beginning in 1958 until the early 1960s. In 1961 it went for around 140 dollars retail. The Messenger 1 consists of a crystal controlled Superheterodyne receiver and a crystal controlled two-stage transmitter. The antenna, power supply, and some of the audio circuits are shared between receiver and transmitter functions.
There are five different models, each with different operating voltages. My Messenger 1 is a model 242-128 that can be powered by 12 Volts DC for mobile, or 117 Volts AC for base station use. For 12 Volt DC operation, the Messenger 1 uses a Interrupter or Vibrator relay to pulse the current through a step up transformer in order to achieve the high B+ DC Voltage required for the electron tubes.
The Messenger 1 has a complement of ten electron tubes and 2 diodes. Its crystal controlled frequency range is between 26.965 to 27.555 Mhz incremented into five channels.
The dimensions of the Messenger 1 are 5 5/8 Inches high, 7 Inches wide and 11 3/8 Inches deep, which is quite bigger than the transistorized CB radios of the 1970s. In addition, it weighs a fairly hefty 12 pounds!
The inside of my Messenger 1 was pretty nasty, several of the electron tubes were missing and one was cracked and unusable. I found a petrified hornets nest laying on the top of the chassis. Still, there was promise. You can see towards the bottom where I wiped the chassis with a Windex moistened paper towel. Somewhere under all of this dirt is a working CB transceiver!
Pictured below is the back of my Messenger 1, on the bottom left is the power connector. On the right hand side is the antenna connection. Through the hole you can see the base of the Interrupter relay, used in the high voltage power supply circuit when powered by 12 Volts DC.
Below is a picture of the Messenger 1 microphone with push to talk button. The high impedance ceramic microphone element is housed in a Cycolac resin case.
The EF Johnson Viking emblem, I plan on cleaning it up then applying red paint to the "J" and black paint to the background around the Viking head.
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I consult this book often during radio restoration. I grew up in the transistor and rectifier era and this book taught me a lot about vacuum tube and selium rectifier technology.
Disassembly and Cleaning
The metal chassis is rusted and pitted, no amount of polishing is going to bring it back to its original luster. The only other alternative is to paint it. The grey oblong thing in the upper right-hand corner of the chassis is a petrified hornets nest.
Here is a picture of the bottom of the chassis. The discrete parts (resistors, diodes, transformer, coils) are dirty but in good condition.
Two out of three of the knobs were missing from my Messenger 1, the third had a set screw with a stripped head that had to be drilled out.
The face plate is held onto the chassis by two brackets and the nuts on the shafts of the Volume and Squelch controls.
Circled below are the screws that have to be removed in order to free the faceplate from the chassis.
Contact cleaner was applied to the Channel selector's contacts. I then moved the Channel selector to all five positions in order to clean the contacts. It is best to do this before the chassis is painted as some contact cleaners will harm paint.
I applied Labelle 107 Oil to the base of all the Channel selector switch and the Squelch and Volume control potentiometers. I have this oil on hand due to my model train hobby. This oil will will not harm plastic components.
I apply Labelle 106 Grease to the bearing of the Channel selector switch that provides the "ratchet" action. This grease will not harm plastic parts.
Labelle lubricants on Amazon
I use Labelle oil and grease for my radio restoration projects. I already have these products around as I am also a model railroad enthusiast. These products will not harm plastic.
The top and sides of the chassis will need to be wet sanded in preparation for paint. First, I removed all electron tubes from their sockets, then I removed many other parts mounted to the top of the chassis so as to make it easier to wet sand and paint. Parts removed included a multi-section electrolytic capacitor, large electrolytic capacitor, Channel selector switch, indicator lamps and the terminal strip. I left the power, Oscillator, and IF transformers in place as these components have multiple connections making them difficult to remove.
The top and sides of the chassis was then wet sanded and rinsed several time, below is the result.
The metal enclosure is faded and will need to be repainted as well. It got a good scrubbing in dish soap in order to remove the grease and grime, prior to paint prep.
Molex pins were added to the microphone and speaker connections so that it can be easily disconnected if needed.
Molded Capacitor Replacement
Much like paper capacitors, molded capacitors become very unreliable with age and should be replaced with one of similar capacitance and equal or above Voltage rating. Molded paper capacitors are not polarized although they may have a black band on one side indicating which lead is connected to the outside foil. Circled below are the molded capacitors that will be replaced in my Messenger 1.
I replace molded capacitors with new Polypropylene type. Circled in the picture below.
Electrolytic Capacitor Replacement
As electrolytic capacitors age, their electrolyte dries up causing their electrical capacity to drop and leakage current to increase. It is definitely a good idea to replace 50 year old electrolytic capacitors like the ones in the Messenger 1!
Electrolytic capacitors should be replaced with one of similar capacitance and equal or above voltage rating. These type of capacitors are also polarized so make sure you observe the polarity of the capacitor to be replaced and install new the same way. At this point I only replaced electrolytic capacitors contained within the chassis. The multi-section and power supply electrolytic capacitors mounted on top of the chassis will be installed after paint.
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Restoring the Multi-Section Capacitor
Multi-section capacitors, which are aluminum cans containing several discrete capacitors all connected to a common ground, were popular in the 1960s. There were used mostly in the power supply sections of vintage electronic devices. You can purchase replacement multi-section capacitors but they are expensive. I typically rebuild them by replacing their guts with inexpensive discrete capacitors of the same or slightly greater capacitance and working voltage. The multi-section capacitor in the Messenger 1 is circled in the picture.
The multi-section capacitor in the Messenger 1 contains the following discrete capacitors:
Capacitor A 15uF @ 300Volts
Capacitor B 10uF @ 150Volts
Capacitor C 10uF @ 25Volts
The wiring connected to it's base terminals, circled below, must be desoldered before removing it from the chassis.
Here is a picture of the multi-section capacitor removed from the chassis. The three solder lugs in the center connect to the positive side of the internal electrolytic capacitors. All internal capacitors share the solder lugs at the rim for their negative connection.
I use wire cutters to uncrimped the bottom of the multi-section capacitor. Then I use needle nose pliers to pull the crimped sections away from the base. This allows me to pull the guts of the multi-section capacitor out of the aluminum can.
The anatomy of a multi-section capacitor. The three internal electrolytic capacitors are rolled up into one assembly.
I was only able to fit the replacement 22uF @ 300 Volts and one 10uf @ 25 Volts electrolytic capacitors inside the aluminum can, the other 10uF @ 150 Volts electrolytic capacitor will be soldered to lugs and concealed within the chassis. Note: The electrolytic capacitor in the picture is only rated 22uF @ 250 Volts. It was replaced with a 22uF @ 300 Volts capacitor after the picture was taken.
I use a Dremel with cutoff tool to remove the area from the base of the multi-section capacitor's aluminum can that I bent with needle-nose pliers.
I then use the Dremel with wire brush tool to remove burrs.
I buffed up the mutli-section capacitor's aluminum can, looks like it did when it was new!
The aluminum can, when glued in place, will conceal the discrete replacement capacitors. You will never know it was refurbished once the aluminum cover is installed! The multi-section capacitor will be installed after the chassis is painted.
Paint and Polish
The power transformer, located toward the rear of the chassis, will be painted first. I lightly sanded the transformer in order to remove any loose paint and rust. Then, I carefully mask off the area around the power transformer. I use a "paint prep" degreaser on the transformer just prior to paint.
I sprayed the power transformer a matte black. Matte works best to conceal surface imperfections.
Time to paint the entire chassis. I carefully masked off the power transformer, tube sockets, and Oscillator and IF transformers. In addition, I applied masking tape on the underside of the chassis to cover many of the open holes so as to reduce the amount of overspray on the internal components.
It is important to choose a paint that will hide imperfections on the surface of the chassis, such as the one from my Messenger 1. I choose Rust Oleum Metallic Paint & Primer in Titanium color. This paint is thicker than the average spray paint, it lays down a "sparkly" finish. Both of these spray paint attributes hide the surface imperfections quite well. See the finished product below:
Rust Oleum Metallic Paint & Primer on Amazon
The metal enclosure was also treated to a fresh coat of paint. I once again used a Rust Oleum Paint & Primer in Hunt Club Green in Satin finish to hide surface imperfections.
The front panel was salvageable and did not require paint. I used Meguire's Metal Polish to bring back the shine.
I think you'll agree that the front panel looks fabulous after polishing.
The final touch was to repaint the logo on the faceplate. I used acrylic enamel paint that I have on hand for my model railroad hobby.
The speaker frame was treated to coat of silver paint, just prior the speaker cone was masked off and the audio transformer was removed.
It was a little more difficult to paint the mounting tabs on the front of the speaker frame. I had to create a masking tape "silo" to prevent overspray on the speaker cone.
Look, no overspray on the speaker's paper cone!
Little parts, such as the Channel selector mounting bracket and the Interrupter socket were also treated to a coat of silver paint after they were properly degreased.
The microphone was disassembled and the Cycolac resin case was buffed to a fine sheen. Meguire's PLASTX works great on Cycolac.
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I use a lot automotive detailing products in my radio restorations. I use Meguiar's products as I have them on hand for detailing my cars.
I carefully masked off the Cycolac case around the microphone clip.
The microphone clip was treated to a coat of silver paint, then the microphone was assembled. I used Armor All to bring back the shine in the microphone's coiled cord. The microphone leads were originally soldered to connections in the chassis, I chose to add Molex pins to the connections so that the microphone assembly wiring could be easily disconnected if needed.
I use a piece of paper with a hole cut in it the diameter of the nut. I then place it around the nut when tightening in order to prevent the paint from being scuffed.
I also place electrical tape on the end of my crescent wrenches to prevent the paint from being marred while tightening nuts.
The power supply electrolytic capacitor was then installed. The original electrolytic capacitor was rated 80uF @ 450 Volts, I replaced it with one rated 100uF @ 500 Volts
I typically replace screws with rusted or corroded heads, they look terrible against the newly painted chassis. I sometimes repaint the heads of screws, that I cannot easily replace, with silver acrylic enamel paint.
The Channel selector switch and mounting bracket were installed next. A transmit/receive pair of crystals are installed in the white porcelain sockets at the top. The Messenger 1 only has the ability of selecting five CB channels, unlike newer solid state models capable of forty channel selection. In addition, the multi-section capacitor was installed, a dab of hot glue at the base holds the aluminum cover of the multi-section capacitor in place.
The discrete pins for the microphone and speaker connections were installed in Molex connectors. A strain relief was added to keep the microphone's coiled cabled in place.
Finally, the terminal strip and the power indicator neon light was installed. In addition, the "mod" or transmit modulation neon light was also installed. That's all the assembly for the chassis.
I installed new rubber feet on the metal enclosure.
A new microphone clip was installed on the side of the metal enclosure.
All tubes were tested prior to installation into the Messenger 1 chassis. Any tubes that had a milky white film were not be tested and immediately discarded as the vacuum integrity had been compromised.
The remaining electron tubes were tested with my trusty Eico 635 Tube Tester. Tested "Good" tubes were installed back into the Messenger 1 chassis.
The Interrupter, also known as a Vibrator, is an electromechanical device that "interrupts" the DC (Direct Current) current flow of a low Voltage, in this case 12 Volts. An Interrupter produces AC (Alternating Current) with high Voltage potential when its output is fed into a step-up transformer, like the one used in the Messenger 1. This is high Voltage is rectified into 370 Volts and 200 Volts DC used to provide B+ to the Anodes of the electron tubes in the transceiver. In the Messenger 1, the Interrupter is only used when it is being powered by 12 Volts DC, as in a installation inside of a vehicle. It uses different circuits when powered by household current with a potential of 117 Volts AC.
The Interrupter employs a coil much like in a electromagnet. At this point I only tested to see if the coil was "open". As you can see from my Digital VOM (Volt-Ohm-Meter), the coil in the Interrupter has a resistance of 99.8 Ohms which is the expected resistance of coil. Good news, the Interrupter passed its initial test and will be installed on the Messenger 1 chassis.
An antenna switching relay is incorporated in the Messenger 1. It is activated when the microphone is keyed, and connects the antenna to the transmitter circuits. By default, when the relay is de-energized, the antenna is connected to the receiver circuits in the transceiver.
I connected a 9 Volt battery to the relay's coil in order to test. The relay contact should pull in when the coil is energized. The antenna relay worked as expected.
I used ultra-fine sandpaper to clean the antenna relay contacts.
I initially tried to power up my Messenger 1 using 12 Volts DC. This was accomplished by connecting jumpers across pins 1 and 2 and also across pins 5 and 7 on the 9 pin power connector located on the back of the chassis. +12 Volts was applied to pin 6 while the pin 9 was connected to the negative connection of my bench power supply. I figured it was much safer to test when powered by low Voltage then to connect it to high Voltage household current, which is rated at 117 Volts AC. My Messenger 1 did not power up under 12 Volts DC.
After a little investigation, I determined that the Interrupter was not passing current to the power transformer. In order to troubleshoot the problem I needed to disassemble the Interrupter to take a look at its innards.
The first step was to uncrimped the bottom of the aluminum can that encloses the Interrupter using wire cutters.
Upon examination, I determined that that Interrupter's contacts had a black film on them that prevented good electrical contact. I used ultra-fine sandpaper to remove the film and then used my VOM (Volt-Ohm-Meter) to verify continuity.
Once repaired, the Interrupter's relay mechanism was stuffed back into its aluminum can. The relay mechanism is typically contained in a foam rubber sheath in order to reduce noise. Make sure you reinstall the sheath. I then used Super Glue to secure the Bakelite base to the bottom of its aluminum can. Rubber bands were used to hold the base in place while the glue dried.
Electrical tape was used to cover the scratches and gouges made to the Interrupter's aluminum can during the uncrimping and disassembly process.
Finally, the Messenger 1 sprung to life, powered by 12 Volts DC from my bench power supply. Once an antenna was connected, I received atmospheric "hiss" on several channels, on one channel an actual conversation could be heard.
Time to test my Messenger 1 powered by household current. The jumpers on 9 pin power connector need to be configured differently to be powered by 117 Volts AC. Pins 4 and 5 are connected together by jumper, in addition, pins 8 and 9 are also connected together by jumper. 117 Volts AC is applied to pins 3 and 6. Success! Once again my Messenger 1 power up under household current. Do not touch the chassis when initially powered by household current until you determine if household current AC "Hot" should be connected to pin 3 or 6. You will need to flip/flop the AC connections on pins 3 and 6 if 117 Volts AC is measured between the chassis and AC circuit ground. As you can see from VOM meter reading below, AC Voltage between chassis and AC circuit ground dropped from 117 Volts to 5.53 Volts AC once the AC connections were swapped.
The faceplate was installed after my Messenger 1 had been throughly tested. The faceplate is attached to the chassis with the nuts on the shafts that hold the Volume and Squelch potentiometers in place. In addition, two brackets attach between each side of the chassis and the right and left upper section of the faceplate.
The metal enclosure slides on from the back. It fits snuggly in place around the front panel. It is important to make sure the microphone cable does not get crimped during the enclosure install process. The metal enclosure is held in place with four sheet metal screws that hold it securely to the chassis.
As mentioned, all but one knob was missing. It was destroyed during the disassembly process as I had to drill out the stripped set screw. I replaced the knobs with black plastic 27mm diameter knobs with set screws, available from Amazon. With that, the rebuild of my Viking Messenger 1 CB Radio Transceiver was complete!
Replacement Knobs on Amazon
My newly refurbished Viking Messenger 1 in action!
Who Writes This Blog?
John is an IT professional from Cleveland, OH who enjoys amateur radio, ham radio, metal detecting,
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