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2270 Very slow relay click

Discussion in 'Marantz Audio' started by Stratman, Jun 8, 2018.

  1. Stratman

    Stratman New Member

    Messages:
    37
    I've just acquired a 2270. The relay clicks after about a minute. I hear a gradually building buzz from the relay until it engages. The audio sounds like a receiver that needs to be serviced but is mostly fine.

    The voltages on the power supply and amps are fine. Is there anything I should try to fix before I dive into recapping the power supply and changing the relay?
     

     

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  2. Jailtime

    Jailtime Standin' on a corner Subscriber

    Messages:
    11,378
    Location:
    Velva ND
    Power supply caps, a new relay, and relay driver transistors should do the trick. Install new differential pair transistors in the amps while you're at it.
     
    catrafter and wlhd1610 like this.
  3. mbz

    mbz AK Subscriber Subscriber

    Messages:
    2,101
    Location:
    Melbourne, Victoria
    C807(220uf/10V), R816(390k) perform the timing for the power ON mute.
    Check each are still OEM and not replaced with anything significantly larger.
    Maybe C807 is leaking->longer to charge up, it's a long shot. Once charged
    C807 should turn ON H809 and H810, consider replacing these transistors.
     
  4. sregor

    sregor AK Subscriber Subscriber

    Messages:
    3,497
    Location:
    Mass
    +1 on previous post. Also C806 (10 uF 50v) can be bad. Will cause low supply voltage for protection circuit only, and slow or no operation and can be the cause of the buzzing too. . Can also be a tired relay but I've not seen it in these. YMMV
     
  5. llwhtt

    llwhtt Super Member

    Messages:
    1,454
    Location:
    SoCal
    I vote for C806.

    Craig
     
  6. tranguru

    tranguru Active Member

    Messages:
    191
    Location:
    Brussels
    same here

    luck
    R
     

     

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  7. Stratman

    Stratman New Member

    Messages:
    37
    Ok, I recapped the board and the problem persists...

    I think the relay itself is probably fine. Once it clicks, it works ok.

    Next step would be replacing H809/H10, correct? The originals are 2SC1213A. Is this mouser an appropriate replacement? 512-KSC2383YTA
     
  8. mbz

    mbz AK Subscriber Subscriber

    Messages:
    2,101
    Location:
    Melbourne, Victoria
    It's only for switching, so yes, also that list of transistor subs has the KSC2383 are a replacement.

    Yep, however another long shot would be H808 failing c-e near short. If possible/if it can be done safely, maybe check the voltage
    at H809b at power on/relay activation, service manual has the base voltage climbing to about 1.25Vdc. Use a mini grabber or ...
    and measure at R816 or 817 or 815. If voltage is significantly less than 1.25Vdc then maybe H808 or ...(resistors?)
     
  9. Stratman

    Stratman New Member

    Messages:
    37
    R816 is measuring 375k and H809B across 816 is....40V? That can't be right. Are you sure you don't mean 808B?

    I'm just going to replace all 3. 808 is a 2SC945, which the transistor replacement sheet indicates can also be replaced with KSC2383. Any reason to use a KSC945 instead? Thanks for the help.
     
  10. mbz

    mbz AK Subscriber Subscriber

    Messages:
    2,101
    Location:
    Melbourne, Victoria
    Apology, don't like probing transistor legs, one slip... Was pointing out a suitable measurement point at one side of R816,,, rather than probing Q809b.
    All memasurements should be with black probe connected to chassis/GND. A sufficiently high voltage is required at Q809b to turn it on and then turn
    on H808.
    upload_2018-7-6_9-6-16.png

    will check transistor subs shortly
     
  11. mbz

    mbz AK Subscriber Subscriber

    Messages:
    2,101
    Location:
    Melbourne, Victoria
    Yeah, for H808, KSC945 is a better match, Will need KSC945C for ecb pinout.
    For H809, 810 (2SC1213) then you need something to cope with the larger
    currents, eg, KSC2383.
     

     

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  12. Dingman

    Dingman Do you know where your towel is? Subscriber

    Messages:
    2,390
    Location:
    Des Moines, Ia
    But but but....
    I don't see a measurement at the coil of the relay?
    That's the first step, divide and then conquer.
    It's an old relay and not airtight. does it pull in when proper voltage applied?
     
  13. petehall347

    petehall347 the brandy coffee man Subscriber

    Messages:
    27,628
    Location:
    uk.. the middle bit
    monitor dc offsets at power on . if it stabilises quickly to near zero volts check every voltage on protect circuit . looks more like bad solder or flaky transistor to me .
     
  14. Stratman

    Stratman New Member

    Messages:
    37
    Transistors are in the mail. Getting 1.2V at R816. Relay works fine otherwise as do the amps. Solder joints have all been reflown.
     
  15. mbz

    mbz AK Subscriber Subscriber

    Messages:
    2,101
    Location:
    Melbourne, Victoria
    H809b as per sm. Looking more like slow to settle transients. Test L&R dc offset by measuring Vdc to GND at
    R811 and 812 or relay solder pads as shown, ie, power on amp then immediately measure/track voltage, may
    bounce around for the first 1-2 seconds however after 4-5 seconds it should be less than 100mV
    upload_2018-7-7_13-41-50.png
     
  16. mbz

    mbz AK Subscriber Subscriber

    Messages:
    2,101
    Location:
    Melbourne, Victoria
    Ooops, H809b is ok, should measure H810b/c/e voltages to ground 5-10 seconds after power on.
     

     

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  17. Stratman

    Stratman New Member

    Messages:
    37
    As we suspected, replaced H810 and 1...2...CLICK

    Thanks all!
     
  18. Dingman

    Dingman Do you know where your towel is? Subscriber

    Messages:
    2,390
    Location:
    Des Moines, Ia
    Well done.
    Now that it's finished, I'm surprised no one called out the "airtight" spec on relay. LOL, I made that up. Was going to defend with some air\oxidation thingy and try to have fun with it. I promise I would have stayed out of the way of real troubleshooting.
     

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