hi new here .

Discussion in 'Microphones, Speakers & Audio Processing' started by PREINSTALLEDSMOKE, Jul 10, 2017.

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  1. PREINSTALLEDSMOKE

    PREINSTALLEDSMOKE QRZ Member

    yesterday i bought a johnson messenger 2 at a estate sale for 1 dollar but it has no user manual. i downloaded a shop manual but cannot find a user manual . how do i hook up a speaker to the unit? in the back of the radio is a ac plug and above this is another round plug. the only no.s i can find is a serial no.0126202 and the fcc lic taped to the side of the radio with mr smick's call sign of kfi1504 that expired in 10-3-1967 any help would be very appriciated. dad used to be in radio repair in the military but he hasn't done anything for the last 30 yrs so he is not much help.
     
  2. W7UUU

    W7UUU QRZ Lifetime Member #133 Life Member Platinum Subscriber QRZ Page

    You can find information on the Johnson Messenger II here:

    http://www.cbtricks.com/radios/ef_johnson/messenger_2/index.htm

    It's a CB - this is not a CB forum so you might want to look into finding a vintage CB site.

    But either way - welcome to QRZ :)

    Dave
    W7UUU
     
    K2XT likes this.
  3. PREINSTALLEDSMOKE

    PREINSTALLEDSMOKE QRZ Member

    i knew it was a cb ,i tried the cb tricks sight and downloaded the service manual but they didn't have the owners manual
     
  4. W7UUU

    W7UUU QRZ Lifetime Member #133 Life Member Platinum Subscriber QRZ Page

    What is it that you're not understanding how to do that you need the owner's manual? It's a very basic radio - 10 channels, hard-wired microphone - just connect a resonant antenna and talk. If it's lacking crystals, that will be a very tough thing to find reasonably priced. Crystals are a thing of the past in a pretty big way, unless you really dig deep for sellers on eBay and other such sites.

    Johnson Messengers were good radios in their day - a fair number were converted to 10-meter ham radio use and did very well.

    I've not found a link to the owner's manual - but there's not much to know. Just ask your questions here and I'm sure you'll find an answer.

    Dave
    W7UUU
     
    N7ANN likes this.
  5. KC8RLU

    KC8RLU Ham Member QRZ Page

    Are there any other jacks on the outside of the radio (rear, front or sides) that you can see, besides the 2 you mentioned earlier? Looking at the schematic in the link Dave provided shows 2 possibilities, but you will need some knowledge of wiring, soldering and/or troubleshooting. One possible route is to locate audio transformer (T4). There may be a green wire on that part.

    Connect a speaker's negative terminal (-) to the green wire (if it exists) and connect the speaker's positive terminal (+) to a red wire (again, if it exists) that connects to a pin on the Transmit/Receive switch (SW2). For the latter, you'll need a continuity tester (this is a common feature included on most digital or analog multimeters; DMMs) and find out which contacts of that switch make connection when the switch is set to receive.

    The second possibility, and this I'm not totally sure of, would be to locate J10/P10 on the main circuit board. There will be either 12 or 24 pins total on that part. Pin 10 would be the negative terminal and Pin 2 would be the positive terminal for a speaker. Pin 2 is linked as a chassis ground, btw. I would try the first option, just to be on the safe side. If that works, then you can say change the setup to add an external speaker jack as a mod to the radio.

    Give it a shot and report back. If you need further help, let us know.

    7-3s (Best Regards) KC8RLU. :)
     
  6. WA7PRC

    WA7PRC Ham Member QRZ Page

    It's an antique 23 channel AM CB radio... the seller got a good price for it.
     
  7. KA0GKT

    KA0GKT Ham Member QRZ Page

    There is a large connector which looks like the Octal socket (It's actually a 12 pin socket) for an old vacuum tube on the back of the radio (J-10). It was meant for a selective call, tone calling unit Johnson made for the Messenger line. Remember, many of the early CB sets were low-output versions of low-band business radios sold by the various companies. ECI Courrier, General Radio Telephone and others did it as well.

    The 12-pin plug which mates with J-10 (P-10, go figure) has some jumpers in it to allow the radio to operate without the selective tone squelch. One of these jumpers runs between pins 2 and 10. It was switched to keep the speaker quiet until the selective call tone was received. You could remove the jumper and place an external speaker across these pins. This will place the external speaker in series with the 3.2-Ohm internal speaker. the radio should be able to drive an additional speaker with a 6-Ohm or lower impedance; however, if the internal speaker has an open voice coil, this will not work.

    Also, unless P-10 is in place on the back of the radio, it will neither receive nor transmit.


    The front facing speaker on the Johnson Messenger II should provide sufficient audio so,unless the external speaker is going to drive an outdoor PA speaker, the additional driver is probably not necessary.
     
  8. W9GB

    W9GB Ham Member QRZ Page

    Why did you purchase this 50 year old E.F. Johnson radio??
    IF this is a cheap -- learn about 50-60 year old vacuum tube equipment -- I would have chosen a post-WW2 vacuum tube SW receiver.

    Estate sale (descendants, auction houses) often don't realize "key parts" missing from older electronics equipment (now antiques). Buyer has to be knowledgable, and smarter than seller.

    This EFJ has a Crystal controlled, single conversion, Superheterodyne receiver with 455 kHz IF.
    With ICM in Oklahoma closing operations in May, there are a limited number of sources for new crystals (e.g. JAN Crystals, Florida).
    Built in the 1960s, it is a vacuum tube design, with interface connectors (9-pin, 12-pin WPI/Amphenol) that are a bit rare (no longer mfg., hence expensive IF missing).
    You will also require access to a tube tester, and basic test equipment (VTVM).

    The Schematic Diagram, provides All of your Answers for your Project.
    EF Johnson Messenger II, models 242-162 and 242-163.
    http://www.cbtricks.com/radios/ef_johnson/messenger_2/graphics/messenger_2_sch.pdf
    IF you can not read a schematic -- you will need to Learn that Basic Skill Set.

    Steve, KA0GKT answered some of your questions.
    CHECK the Squelch Control ...

    SPEAKER : LS-1 at output of the T-4 transformer.
    As I remember, ALL of these Messenger speakers are inside unit (grille on front panel).
    The Speaker is MUTED, when the Push-To-Talk (PTT) switch on Ceramic microphone is pushed.
    The P-10 plug must also be properly jumpered.

    LOWER LEFT : Wiring for AC wiring, as well as DC for Mobile operation.
    LEAVE wired for 120 VAC.

    LOWER RIGHT : Pin Assignments for the other "Rear Connector" (J-10, 12-pin).
    Steve has already discussed, schematic shows pin assignments.
     
    Last edited: Jul 16, 2017
  9. WA7PRC

    WA7PRC Ham Member QRZ Page

    Exactly. If it's clean, at best, it belongs in a museum. Otherwise, anything manufactured in the past two decades or so will perform MUCH better, and cover ALL 40 channels. Some even operate SSB mode as well as AM.
     
  10. KL7AJ

    KL7AJ Premium Subscriber QRZ Page

    Actually the Johnson Messenger was built for commercial use below the CB band. Yes, there used to be a business band at 25 MHz!
     

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