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Is it possible to repair radio ?

Discussion in 'Radio and Wireless' started by scudo, Jun 25, 2021.

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  1. scudo

    scudo

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    Jun 25, 2021
    Background, I have no knowledge of electronics but have a multi meter.
    Radio was very occasionally turning off, I fiddled with the mains cable and usually came back on and good normally for a few weeks, so I though a dodgy cable. Recently is started again but would not stay on so took the mains cable out and put batteries in but the same happened so not the cable.

    I cant see anything physically wrong ie loose cable or scorch marks, is there anything I could check using multi meter and possibly replace (I have soldering iron).
    I would need instruction as have no electronics knowledge. Images attached. 3.jpg
     
  2. Bluejets

    Bluejets

    4,875
    1,018
    Oct 5, 2014
    Intermittent faults are difficult to locate however you could start in and around the switch area and test for loss of battery voltage.

    The photos are a good addition however it is not possible to enlarge by clicking on each image.
    Not sure how they normally do it but someone here will know.
    Basically wanted to get a closer look in at the pcb side.

    Would help to show more detail as leads just disappear off the edge or hidden in the photo.
    Model and make may help also.
     
    scudo likes this.
  3. scudo

    scudo

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    Jun 25, 2021
    I will attempt better images later today.
     
  4. scudo

    scudo

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    Jun 25, 2021
    Radio is a Bush dab model BD-1706
    The radio does turn on but flashes `not connecting to radio station` So power going through.

    a.jpg b.jpg c.jpg d.jpg e.jpg f.jpg
     
  5. dave9

    dave9

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    Mar 5, 2017
    Since fiddling with "the mains cable" helped, I would wonder if your power socket has weakened contacts or broke the PCB solder joints and that this power socket has an internal switch mechanism to cut in/out the batteries and it is now a high resistance.

    As far as anything you can check with a meter, sure! Trace from the power input all the way to all the ICs, get datasheets and see if they're getting power and a good ground. Look over all solder joints for cracks.
     
  6. Bluejets

    Bluejets

    4,875
    1,018
    Oct 5, 2014
    Looks to me like this has already been "attacked" due to the chook scratch solder repair done on the input capacitor link J11.
    Other plug/sockets appear to be bent out of shape also.
    It is quite obvious which is the power in etc. as the board is relatively well marked.
    Is there lack of signal on both digital and fm reception..?
    As Dave says, check for cracked board and /or bad joints.
     
  7. scudo

    scudo

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    Jun 25, 2021
    chook? The radio is from new so in theory I am the only one that has accessed the innards and apart from taking images have done nothing to it.
     
  8. 73's de Edd

    73's de Edd

    3,105
    1,312
    Aug 21, 2015
    Last photo:

    Bottom right corner . . . .6 pin pad connections.
    Has an errant drop of hot solder . . . bridge . . . landed on top of pins 4 and 5 ?

    Also MOST of the other pins don't look like that they were initially FULLY solder wettted and thereby accomplishing a totally melded solder reflow of their connections.

    The function here is a dual right and left channel . . .VL1 . . . volume pot and assuredly its not handling active audio, but a variable DC voltage voltage that it creates to feed into the nearby IC.
    Inside, the bias alters a variable transconductance gain stage to run both channels volume up and down.
    If (4) and / or 5 has one pin being ground, no voltage gets to either stage to permit any volume up adjustment.

    [​IMG]
     
    Last edited: Jun 27, 2021
  9. scudo

    scudo

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    0
    Jun 25, 2021
    I dont understand most of the terminology, are you saying however that pin 4 / 5 should not have that bridge of solder?
    In which case should I resolder them?
     
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