Radio from Volvo car

Discussion in 'General Electronics Chat' started by sreviz, Oct 26, 2016.

  1. sreviz

    Thread Starter New Member

    Oct 26, 2016
    7
    0
    Good morning,
    I joined this thread from hearing about another thread for my car.
    Iam from London and working as a Chef.
    I would love to do my own repair mechanically and more recently want to do my electronic repair as well like replacing LCD screen changing micro USB port for my broke USB port.... Stufflike this with small works.

    Yesterday I was soldering a 3.5mm wire to the radio unit in Volvo xc90 to create an aux input , so I can play mp3 from my mobile.

    After doing all the work as said in the above forum- solder left wire to one capacitor and right wire to another capacitor and ground to one point in PCB-but the speakers working in right side only.
    But when playing CD player all speakers working. But with the aux plug in no sound from left speaker.


    What could possible mistake I've done please.
    Can some one shed some light on this .

    P.s first time when I switched the unit after done the work I stupidly didn't give proper earth . the radio unit serves as a whole like earth but I made a mistake. Will this done a blow in circuit board.
    Or the 3.5 mm plug .
    Please some One help.
    Thank you
    Saravan.

    Below is some pics of the work. Thus circuit board is same like the one attached PDF guide where I got the information.
    Thanks again .
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  2. AlbertHall

    AAC Fanatic!

    Jun 4, 2014
    6,221
    1,446
    I can't see any picture of where you have soldered the three connections to the board so I cannot tell what is wrong but here are some guesses.
    1. The wires you are soldering are stranded and maybe one of them has a strand sticking out and shorting to some other connection nearby.
    2. The insulation on the wires is easily melted by the heat of soldering and this heat can travel up into the cable and damage the insulation inside the cable causing a short within the cable.
    3. You cut the wrong track by R9 or accidentally cut another nearby track as well.
    4. The track by R9 is not completely cut.
    5. There is some problem with the cables not caused by you.

    For 1 to 4 very careful inspection should reveal the problem.

    If you have a multimeter, with the unit switched off and not connected to your phone, check resistances as follows:
    From the outer connection of the plug to the radio chassis - this should read very close to zero ohms.
    Between the inner and outer of each plug - these should not read zero ohms and the two plugs should read approximately the same.

    With the radio switched on and not connected to your phone, hold the metal part of screwdriver and touch the centre pin of each plug with the tip of the screwdriver. You should hear some clicking/scratching/buzzing sound from one of the channels.
     
  3. sreviz

    Thread Starter New Member

    Oct 26, 2016
    7
    0
     
  4. sreviz

    Thread Starter New Member

    Oct 26, 2016
    7
    0
    [​IMG][/URL][/IMG]
    Good morning,
    Thanks for the advice. If you look a the following image I solder the left and right speaker wire from 3.5 mm cable the capacitors C301 and C872 on the positive side. Those are the two capacitors above the five bottom lined capcitors.
    Ground is near those capacitors you can see a big blop of solder. That's where I attached it.
    original guide from another user I attached in the PDF format. Please have a look .
    Mean while I will use your advice to sort the issue.
    Thank you
    Saravan.
     
  5. sreviz

    Thread Starter New Member

    Oct 26, 2016
    7
    0
    Here is the PdF of the page where I use as a guidance for this DIY.
    Thank you.
     
  6. sreviz

    Thread Starter New Member

    Oct 26, 2016
    7
    0
     
  7. sreviz

    Thread Starter New Member

    Oct 26, 2016
    7
    0
    Right . I've just touched the three points from the 3.5 mm plug and found that there is no sound from the left but some buzzing sound from the right.
    Do you think I blown my capacitor?
    Thank you
    Saravan.
     
  8. AlbertHall

    AAC Fanatic!

    Jun 4, 2014
    6,221
    1,446
    I have no information to make that judgement.
    Can you make the resistance checks?
    Can you take a close up picture of your wires soldered to the radio board?
     
  9. MrAl

    AAC Fanatic!

    Jun 17, 2014
    5,137
    1,112
    Hi,

    If you made a mistake an blew something out it is going to be very hard to figure out what is wrong. If all else fails, try removing the wire you soldered and see if you get proper operation back.

    Just curious, are they using a security code too for that radio after power has been disconnected in order to restore operation once power is restored (theft protection) ?
     
  10. JUNELER

    Member

    Jul 13, 2015
    181
    25
    Hi,
    I look the pdf and shown a good pictures did a proper soldered accordingly given C301 and C872.
    and working fine. So , i think if u review the one you done and find no wrong,it should work too.
    but if not let removed again the wiring and cleaned and test .if it worked,do it again start in step one.
     
  11. sreviz

    Thread Starter New Member

    Oct 26, 2016
    7
    0
    Thank you
    Thank you for all your guidance. As all of yiy said I did a big mistake by using a thicker solder tip to do the work and Burnt the wire itself and ruined it.
    I removed it and tried resolder it in a near by shop who does the laptop for 5 pounds.
    And voila job done.
    Thanks for a detailed explanation and guidance. My aux plug is working like a charm. Mean while I live in London UK.
    Can some one please advise or recommend me solder with fine tip thru eBay which is good and cheap. I don't want to incest big amount as Iam a hobbyist doing small works only like obike phone charger plug some thing like that. I saw Weller solder with fine tip but it is too expensive to invest in it.
    Thanks again
    Saravan.
     
  12. AlbertHall

    AAC Fanatic!

    Jun 4, 2014
    6,221
    1,446
    Try to find a cheap one with alternative size/shape tips available then you can choose the one right for the job.
    Weller are good (I have one which I have had for many years but, yes, they are not cheap) but any cheap iron will do the job too.
     
    sreviz likes this.
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