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Identify this component

Discussion in 'General Electronics Discussion' started by atha, Apr 28, 2013.

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  1. atha

    atha

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    Apr 28, 2013
    Hi!

    What component is or was this and what values could it have had and were do I find a new one?

    It is an empty housing. It's from an old radio.
     

    Attached Files:

  2. quantumtangles

    quantumtangles

    152
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    Dec 19, 2012
    Frequency adjustment pot...I think. If you adjust these things (normally they are colour coded and several of them are often seen on old transistor radio boards) you can pick out frequencies outside the normal range of the radio (e.g. restricted stuff).

    The radio experts here will know precisely what component it is but they will probably want to see an overhead shot of the component (alongside a ruler or other comparator).
     
  3. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,497
    2,839
    Jan 21, 2010
    Packages like that often held RF and IF transformers that were used between stages of early transistor radios.

    Search for "if transformer" on ebay.

    If you're looking for a replacement it's probably not going to be easy.
     
  4. atha

    atha

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    Apr 28, 2013
    It is from an ols radio from 1974. I've attached an image of some of the inside of the radio. Here you see more of these metallic components.

    Can the numbers on the old one tell which colour it had?
     

    Attached Files:

  5. duke37

    duke37

    5,364
    772
    Jan 9, 2011
    !974 old? What about 1924?

    If you can find the make and model of the radio you may be able to find a circuit diagram (schematic) and work out what inductance is missing. The next problem will be to find a substitute if you wish to repair the radio.

    It may be an intermediate trnsformer or tuned circuit or it may be an inductance for an oscillator or for the radio frequency input.

    They are constructed with a little pot core and sometimes have a capacitor in the can as well.

    Someone more skilled than me may be able to divine the circuit but the frequency will still not be known.
     
  6. davenn

    davenn Moderator

    13,866
    1,958
    Sep 5, 2009
    well it isnt going to be 1924 with transistors in it ;)

    yup to all that :)

    to the OP ... why do you want to replace it ? did you snap the ferrite ?

    Dave
     
  7. quantumtangles

    quantumtangles

    152
    3
    Dec 19, 2012
    Please let us have more photos from different angles.

    There is a treasure trove of information marked on the components of this old radio and elsewhere, but we need to know, for example, the numbers on the transistors, the brand of the radio if possible (it does not look Japanese...not well enough built...which makes me doubt myself given the vintage).

    Is there a case for the radio that has a name on it...is there a brand name on the electrolytic capacitors...give us all the data you have (everything) and lots photos from different angles.

    What numbers are marked on the crystal oscillator?

    Looks very interesting.
     
    Last edited: Apr 28, 2013
  8. atha

    atha

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    Apr 28, 2013
    It is not in very good looking shape. I bought it from someone about 25 years ago. I don't recall why I desoldered the component.
    Kept it because I thought I could mend it. Now many years later I found it in a box in my cellar. I keep it ust as a memory of that time and the guy I bought it from.
    Would be nice to get it working again.
    It's a Midland 13-723 handheld transiver 3 channels and 2w. It doesn't look pretty inside. Looks like the component had been thrown on to the pcb :)
    I have another old handheld from 1960'ties I think with one channel and am radio. It looks better inside.

    Here is an image of the inside
     

    Attached Files:

  9. quantumtangles

    quantumtangles

    152
    3
    Dec 19, 2012
    The model number would have been helpful, but based on available data, you appear to have a transceiver from the Midland 13 series. It may be a Midland 13-700 or at least a member of the 13-700 series family (for example, a 712 or some such other model from the same series).

    Have a look at this circuit board from a working Midland 13-700

    http://www.aepsurplus.com/program/fixedpriceMod.cfm?do=detail&productID=709&categoryID=98

    My best guess is that the missing component from your device had a white top. But I am working on my laptop and have not had a chance to magnify the comparator board using high resolution imaging software...as I recommend.

    There are dark blue, light blue, pink, white and yellow adjustable components on boards made by Midland from the same period. The same components may have been used even as board layout varied (for example, they may have preferred to use components already in stock at the factory).

    The comparator is also apparently a 2 watt 3 channel transceiver, though the board layout is slightly different. The crystal oscillators in your device have a characteristic layout not seen on the comparator board. They are in line on your board and one oscillator is 'missing', though the component slot may not have been populated deliberately (so they could use the same board for other models).

    Hope this helps.
     
    Last edited: May 1, 2013
  10. atha

    atha

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    Apr 28, 2013
    It is a Midland 13-723.
     
  11. davenn

    davenn Moderator

    13,866
    1,958
    Sep 5, 2009
    Quantumtangles !!
    what on earth are you talking about ??

    Did you not read atha post before yours ? he gave the model # ;)

    what's this comparator you keep referring to ?? the unit is a CB radio transceiver

    what the ... ??? thats a VERY common way of having plug in crystals so that the channel freq's can be changed at leisure. They are JUST crystals, the rest of the oscillator is on the circuit board. one set of crystals for receive, the other set for transmit

    Dave
     
  12. atha

    atha

    8
    0
    Apr 28, 2013
    It is a Midland 13-723.

    Don't know why it only had crystals for two channels. I'm sure it had three when I bought it.

    Hard to see what the colours are but it lookes like there are two whites. Perhaps the red one is pink and just looks red in this image. If you are certain they didn't use reds, it has to be pink. I have the pink so either it is a yellow or white. But then again, the numbers printet on the the other yellow and white does not match those on the empty housing.
     
  13. quantumtangles

    quantumtangles

    152
    3
    Dec 19, 2012
    I did not spot the model reference in the earlier post so tried to track it down. This was due to carelessness on my part unless the post was amended ex post facto my response.

    The comparator = the closest board I could find made by the same manufacturer in the same period.

    The difference between the two circuit boards seemed mainly to be in the layout of the crystals...in a line on the board in question but all over the place on the similar board I found online. I was inviting attention to the fact that the boards were not identical. Apologies for any confusion. It is my fate to be inarticulate, to misunderstand or to be misunderstood. Not sure which.

    The missing component is essentially an adjustable inductor (in fact, two tiny inductors in a little metal box). Turning the screw adjusts the inductors and changes the frequency that can be picked up by the receiver.

    Inductors are simply wire coils. Accordingly, to fix your transceiver, you should be able to attach a coiled piece of thin wire to the terminals where the missing component once sat. If you do this, and everything else is working properly, the transceiver should work. Play around with different lengths of wire and numbers of coils. You could also wrap, for example, about 15 coils of really thin copper wire around a ferrite (not iron) core as this will increase the inductance considerably when compared to a wire coil without a ferrite core. An iron core will probably cause too much interference.

    As these devices come in pairs, have a look around for the counterpart transceiver as well :D
     
    Last edited: May 2, 2013
  14. davenn

    davenn Moderator

    13,866
    1,958
    Sep 5, 2009
    LOL QT,

    you had me worried ... I thought you must have just come home from a good party ;)
    and if so was also wondering why you hadnt invited me haha


    Wont be quite that easy, the variable inductor may or may not have a primary and secondary winding. the adjustable ferrite slug will also be specific
    Without a circuit diagram its hard to tell if that coil belongs in the transmitter or receiver lineup

    Atha .... you didnt answer a question from me earlier ....
    why was the coil removed from the board ? why was it suspected as faulty?
    the only way these thing fail is if they are physically abused .... the ferrite slug cracked or whe whole can crushed

    OK I found this in one of your posts ....
    OK check that coil does it look physically damaged ? any pins missing from bottom of it?
    VERY GENTLY try and turn the slug with a flat blade screwdriver does it turn ?



    Dave
     
    Last edited: May 2, 2013
  15. atha

    atha

    8
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    Apr 28, 2013
    Made it sound like I kept the component for mending. I ment the transceiver. I only kept the housing of the component. Sorry.

    I am frequently looking for a transceiver similar to this on ebay. But never found the same model.
     
    Last edited by a moderator: May 2, 2013
  16. davenn

    davenn Moderator

    13,866
    1,958
    Sep 5, 2009
    yes I thought you still had the coil

    OK so you are not going to make one ... its going to have a pretty specific purpose in there
    If you can get another transceiver thats faulty you may be able to very gently remove the same coil and replace it into your current unit

    Dave
     
  17. atha

    atha

    8
    0
    Apr 28, 2013
    So you don't think it is possible to find a new component like this any more?
     
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