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modification to my old radio

Discussion in 'General Electronics Discussion' started by guitar89, Jan 22, 2011.

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  1. guitar89

    guitar89

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    Jan 22, 2011
    I have an old radio (well... maybe 10 years or so) which the CD player is faulty, and tape feature(which most of us didn't use nowadays).
    It doesn't have any line-in for me to input any other audio hardware which i can make use of the radio (as a speaker).
    I kind of like it, so I decided to modify it make it useful.


    My idea was to rectify the CD input into a line-in port, which most modern music players have. I'm also interested to hear others idea and opinion.

    I have the manual of schematic circuit drawing of that particular radio player called PHC-ZW770L.
    But I myself couldn't fully have the idea where should I edit it, as I only have little knowledge about audio. These are the following problem i'm facing:
    - As commonly known, a stereo adapter have 3 wiring, which is ground, Left & Right. I'm thinking of connect these 3 wiring of another line in cable to take over CD's wiring.
    In the circuit board, i only found/know it have a L&R-channel input, but i didn't found any words match of grounding purposes. ( the part consists of wiring such as "R.CH", "L.CH", "CD.5V(CD-H)", "CD.GND", "P.GND", "P.VDD(6.2V)"

    - Is it possible to just disconnect the wiring for CD's and Tape' to save electricity(as in didn't use at all), or we need to edit a little bit to do so ? (like changing resistors as so on).
     
  2. davenn

    davenn Moderator

    13,877
    1,964
    Sep 5, 2009
    yes you could cut an insulate the power leads to the CD and tape units, I would assume they are low voltage (~12V) (without seeing the cct diag to confirm)

    Then you could cut away and redirect the shielded audio leads from the tape and CD units to sets of RCA terminals on the rear of the case
    That would give u 2 sets of inputs ... MP3 player and something else ... say an external CD player

    cheers
    Dave
     
  3. guitar89

    guitar89

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    Jan 22, 2011
    Thanks for the advice. WOW, i would like to cheers for it (never thought of having 2 input !) but i thought the tape line would be mono channel ? (if i'm not mistaken, tape by itself is mono, so the original design would also make the connection into MONO)
    So that would make it to 1 stereo and 1 mono input line !

    But there is things i'm not certain about, such as the circuit and connection of the audio cable to the terminal of CD/tape input (dunno which connect to what/where)

    The possible terminal i found inside the circuit (from main board to CD board) as follows :
    (apply to TRS Cable/Port, to input source)
    - "R.CH" --------- Most likely to be 'Ring" terminal, which go to right channel
    - "L.CH" --------- Most likely to be 'Tip' Terminal, which go to left channel
    - "CD.5V(CD-H)" ----- Don't know what it would do, except it related to logic gate
    - "CD.GND" ------- Connect it to the 'Sleeve" Terminal, which go for ground ?(uncertain)
    - "P.GND" ----------- Power supply for CD ? So shouldn't do anything to it ?
    - "P.VDD(6.2V)" -------- Also power supply line for CD player ? leave it there ?

    I was wondering I could upload some photos and schematic diagram of it to here or not ? Is it legal or any rules against it ?
    If it is possible, i want to upload some photo on the radio and the schematic diagram manual on here, making the jobs for other easier.
    So we could also find out if the power for CD/Tape is cut off, anticipate the effect would bring. (best to prevent catastrophe from landing to my device)
    Would appreciate if more people gives advice, suggestion on this modification !
     
  4. davenn

    davenn Moderator

    13,877
    1,964
    Sep 5, 2009
    well it would be mono if it was a very old tape deck. Most, if not all tape decks in the last 10 yrs would be stereo sound.
    The audio cable from it would confirm that :)

    Yes please upload some pix show the cable connections to the tapdeck and CD circuit boards make sure they are sharp (well focussed)

    Dave
     
    Last edited: Jan 23, 2011
  5. guitar89

    guitar89

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    Jan 22, 2011
    OK dave, i will take my best shot ! Can I upload the circuit diagram manual up to here ?
     
  6. guitar89

    guitar89

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    Jan 22, 2011
    I uploaded some pictures, but i don't that is gonna help.... too complicated.

    I wanted to upload the circuit diagram manual, but the file is too big.....

    The photos aren't clear because of limited upload size too.
     

    Attached Files:

  7. guitar89

    guitar89

    5
    0
    Jan 22, 2011
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