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Pioneer A-503R, speakers relay #ASR-112 replacement

Discussion in 'Datasheets, Manuals and Component Identification' started by spanish_inq, Jun 21, 2017.

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  1. spanish_inq


    Jun 21, 2017

    recently I bought a Pioneer A-503R amplifier. One speaker channel is sometimes quieter. I read that
    this is probably the faulty relay problem. I will clean it with IPA. If this will not help or maybe contacts are bent or spring lost its strength, I'll replace the relay, but I cannot find a replacement part.
    In Service Manual I found that the relays have part number ASR-112.
    Could someone help me and tell what replacement relay could I use?

    And this is my first thread, so Hello from Poland! :)

    Best Regards
  2. davenn

    davenn Moderator

    Sep 5, 2009
    Hi there
    welcome :)

    how about a link to the service manual please
  3. spanish_inq


    Jun 21, 2017
    Last edited: Jun 21, 2017
  4. 73's de Edd

    73's de Edd

    Aug 21, 2015
    Sir spanish_inq . . . . . . .(uisition)

    That’s being an obsoleted relay now . . as an OMRON G5R-2232-PG .

    I can’t ascertain if case height obstruction is / could be a problem, from your picture.

    Can you get side DC coil specs from the original relays.

    I think that a currently available OMRON G2RG-2A4 which is a DPST-NO type will replace it

    BUT first . . . . listen to some continuous type music and firmly, do multiple whacks to the the top of the individual cases with a plastic screwdriver handle . . . . . to see if sound cuts in or out.

    73’s de Edd
    Last edited: Jun 21, 2017
  5. spanish_inq


    Jun 21, 2017

    sorry for the little delay.

    It turned out that the seller didn't quite got the description right.
    The amplifier works; but sometimes, not always, in one channel, mostly left (I heard
    it in the right channel also) you can hear qutie loud cracking/static noise,
    a little music, quieter than the other speaker. But this noise stops after few seconds, then comes back, and then stops and it can be fine all day.
    It also appears when I change source (electric buttons with little engine changer inside the case). It also can appear for a short moment (one, few seconds) during the listening and then its gone.
    I hit relays many times and it did not help nor got worse, so this is not the case probably.

    I cleaned the volume potentiometer, but the cracking sound/noise is still there, and moving the volume knob doesn't make any change, so this is also not it I think.

    So, to sum up:
    • it apperas when I start playing music after a break (after this weekend it appeared again, friday it was ok after some troubles)
    • it appears sometimes when I change the source (everywhere, it does not matter that my CD is connected to CD input or TAPE1, etc.)
    • potentiometers are not the issue (they work silently and fine), I'm also listening on Direct.
    • relays are also probably not the problem
    • after long listening session the issue somehow disappear, I can change source without this noises, etc.
    Could someone help somehow?

  6. 73's de Edd

    73's de Edd

    Aug 21, 2015
    Sir spanish_inq . . . . .

    I see that the unit has the capabilities of taking in audio inputs from:
    • Tuner
    • CD
    • Line / VCR
    • Tape 1 Play and Rec
    • Tape 2 Play and Rec

    I also see that the main R and L power amplifier portions of the unit are using discrete component construction instead of an “AMPLIFIER in a sealed black box” . . . . . ( POTTED MODULE) type of construction.

    I also heavily suspect THAT section is being the area of the trouble, with some semiconductor breaking down and avalanching just for the instant(s) that you are hearing the loud pop/snap/crashes.

    Otherwise it is being GOOD for 98% of the other time.

    Gradual shift of temperature of operation of a part might be the factor triggering that, at either some cool condition at turn on, then passing up through a gradual temperature rise variance, until it finally reaches its normal operational temperature.

    If being my problem to analyze and then pinpoint the problem area . . . .

    I would put the FUNCTION switch to LINE/ VCR and have nothing plugged into those inputs.

    Then the first listening session would be to have the balance control at mid range and volume up to about half of max position, so that you should definitely hear any POP sounds while you are in the room but working with another task, as it just might take an hour(s).

    If you get that POP you need to differentiate between origin from Left channel or Right channel or both.

    (If you look at page 6 you will see that 11 transistors are direct DC coupled within your power amp section of a single channel, so if a semiconductor acts up, you could hear a snap, crackle, pop or bacon frying sizzles that would be created at those bad times. )

    If you are not able to differentiate, if it’s only being of such short duration . . . . then . . . . ..

    You set up again for another day where you swing the balance control to extreme Right or Left channel and wait for the noisy effect to come along.

    If no result within those several hours , swing the balance to the other channels extreme and wait out that day.

    Once the channel is isolated, you take that channel and see if the effect is present on another test day on that previously bad channel, but this time with the volume down at minimum.

    These procedures may be sped up if you are LUCKY and it starts showing up its problems quickly. . . . I was just expecting a possible worst case intermittent.

    You would want to have thus ascertained what is being the bad channel and does the volume control have an effect upon its level of severity.
    • After long listening session the issue somehow disappear, I can change source without this noises, etc.
    This suggests that the problem is most likely to be present from a stone cold start up to the temperature where it finally reaches a stable operating temp.

    Questions ?

    73 de Edd
    Last edited by a moderator: Jun 26, 2017
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