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Marantz Model 4300 needs help

Discussion in 'Marantz Audio' started by AsRock, Apr 27, 2018.

  1. AsRock

    AsRock New Member

    Messages:
    43
    Location:
    Pittsburgh
    Hi, about 2 weeks ago i came across a Marantz 4300 how ever it has issue's. I am no expert but i do like to fiddle and do have a love for good music which puts me in some sort of rock and hard place. All so would like to hear it before any thing else as i might like it as much as my 90's Yamaha stuff.

    Option 1 would be to take it apart and sell it, surly be the simplest way. although it's not a option i want to take if possible.

    Option 2, well this is why i am here,

    So here's the problem list besides some idiot(s) messing with it ( no not me ).

    No sound though any outputs
    Got sound though front headphone socket how ever a hum when the left\right slider is moved to one side ( right if i remember correctly).
    Rear headphone socket no sound at all when plug in fully, how ever if half plugged in you can get sound as it's being plugged in.

    Smaller issue's and not all that concerned all that much at this time.

    Plastic needle for tuner is broken ( right type glue could fix this hopefully )
    The plate that the needle rides along the bracket, the brass part as released like the riveting has failed.
    String has broken

    The good, powers on all all lights up fully not perfect but good enough for me for now at least and tuner works.

    My thoughts is that some thing is wrong with the preamp, but made me wounder why the headphone socket works, maybe it has it's own preamp ?.

    I been passes a few messages back and forth with Mark @ Blueglow Electronics and he's suspecting a power supply \ Preamp issue. Again Thank You Mark for responding with the little time you had.

    So i was wondering what voltage should i be seeing from the transformer ?, I am all so seeing 36v and 14V on the power supply from the black transistors on that board.

    H801 35.5v 36v
    H802 36v 51v 36v (BCE)
    H803 36v 36v 8v ( ECB)

    Thanks.
     

     

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  2. mbz

    mbz AK Subscriber Subscriber

    Messages:
    2,101
    Location:
    Melbourne, Victoria
    Maybe take a look at zener diode H808 (7.1V?). 36Vdc on H803e suggests the diode has failed open circuit. Perform a diode test, amp powered off/unplugged.
    You should also diode test H801,2,3, normally don't expect the exact same voltages on 2 legs.

    Nice graphic from markthefixer, 2 results expected, either 650mV or OL/open loop, open circuit.
    Red and black refer to multimeter probe orientation.

    DiodeTest.JPG
     
    AsRock likes this.
  3. jstang

    jstang Honey,I can't hear you... Subscriber

    Messages:
    3,505
    Location:
    Northern Jersey.....
    Service and User manuals will do wonders. Never turn the rear panel 4/2 channel knob with the unit powered up....actually you should wait 30secs or so after power it off.

    The headphones are powered the power amps.
     
    AsRock likes this.
  4. mbz

    mbz AK Subscriber Subscriber

    Messages:
    2,101
    Location:
    Melbourne, Victoria
    You have multiple issues.
    No output through speakers may indicate a protection issue or switch/contact
    or solder issue. Output through front headphones suggests those channels are
    in reasonable condition. Not sure what to make of partly unplugging rear
    headphones->restores one channel, maybe it's breaking some circuit, maybe
    bad/damaged contacts...

    As a basic health check, can you measure the dc voltages at pins 1->7 of J801
    Need to sort out the issue with H808. Also don't short the pins, if too difficult
    will find alternative test points

    It would also be good to check for excessive dc voltages on each of the channels.
    Measure at JN01,2,3,4, black probe connected to chassis/black spkr post.
    J801.JPG

    4300Relay.JPG
     
    AsRock likes this.
  5. AsRock

    AsRock New Member

    Messages:
    43
    Location:
    Pittsburgh
    That second picture is of the rear of the unit with the relays correct ?.

    Sorry it's wife day so not much time HA!, should be able to get back to this tomorrow so i am not ignoring anyone just thought i would say :p. And what time i have had had to go to a ebuyer for a T753 i just sold and he's saying it's working perfectly except it's tripping when uses the switched plug on the rear with some BOSE Active EQ which his Yamaha Z1 died and stuck in protection mode. i am just hoping he don't kill it. Anyways.

    The more info i have the better and thank you.
     
  6. AsRock

    AsRock New Member

    Messages:
    43
    Location:
    Pittsburgh
    Ok had a little time

    H801 pin1 to 7

    50v
    9v
    50v
    0v
    35.2v
    13.5v
    21.4


    How ever pin 4 is not making any contact so will have to check more on that

    H808
    7v
    0.1v


    Yeah i have seen that warning before been looking in this for the passed week now and noticed that warning on a ebay listing lol., but thanks for the reminder.

    Well better get some sleep.
     
    Last edited: Apr 29, 2018

     

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  7. AsRock

    AsRock New Member

    Messages:
    43
    Location:
    Pittsburgh
    Well just checked the JN connection's

    JN02 0.7v
    JN02 37v (eek )
    JN03 0v
    JN04 0.7v

    Thank You.,
     
  8. wlhd1610

    wlhd1610 Penny and her new friend Sponsor Subscriber

    Messages:
    2,462
    Location:
    Catskill NY
    Catrafter is the resident 4300 guru here.
    Send him a PM.

    Bob
     
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  9. mbz

    mbz AK Subscriber Subscriber

    Messages:
    2,101
    Location:
    Melbourne, Victoria
    0.7Vdc is borderline to trip protection, 37V indicates a failed component/connection in Right Rear channel.

    Previous measurement on H803e (post #1) had 36V, this is the same as H808 cathode measured 7V.
    Zener might be intermittent or bad solder joint.

    J801 pin1 to 7

    50v.....probably ok, no guidance on sm
    9v......dunno, no guidance on sm
    50v.....Sm has this at 0.7V, suggests no current through R818
    0v......GND, ok
    35.2v...ok
    13.5v...ok
    21.4....probably ok, no guidance on sm

    Multiple issues, suggest sort out the power supply (P800 board) first because of flow on effects

    More the merrier, just holding the fort til the cavalry arrives
     
    AsRock likes this.
  10. catrafter

    catrafter Marantz Specialist Subscriber

    Messages:
    6,143
    Location:
    Montana
    MBZ is correct about JN04, RR power amp issue.

    I would hate to see this parted out, I have worries about it being repaired by a novice with help over the Internet.

    Asrock, where are you located? I think you may have to find someone with hands on experience with Marantz quad receivers to fix this.
    There are some good techs here on AK, perhaps one of them is near you and has time to take it on in the near future.

    Tom
     
    AsRock likes this.
  11. AsRock

    AsRock New Member

    Messages:
    43
    Location:
    Pittsburgh
    Updated my profile, how ever shipping would be a pain. We do have a Marantz dealer near us but even if they would take i would hate to see how much it would cost lol.

    I have no option but at least try and see if getting the power supply board working will lead some were.

    I know all the caps in this should be replaced as every single is original even more so on the power board.

    Thanks.


    Just need to get some spare time and test these and other parts of the power board.

    Thank You
     

     

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  12. mbz

    mbz AK Subscriber Subscriber

    Messages:
    2,101
    Location:
    Melbourne, Victoria
    The power supply should be first priority, however if you have some spare
    time then here are some notes on the +37Vdc on right rear channel.

    37Vdc is the power supply rail on the power amp stage. The 2 common
    scenarios are
    - a component connected to the positive rail has failed short
    - a component on the negative rail has failed open

    Being "exactly" the +ve rais voltages I would take a punt on a c-e short
    on H006 or H715(sucker bet?). The systematic approach would be to diode
    test the transistors starting with the outputs H005,6, then work back, ie,
    H715, H716,,

    The diode test is not definitive, a fail indicates a faulty item. A pass
    indicates item may be faulty, b/c/e voltages are often needed to identify
    these components.
     
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  13. AsRock

    AsRock New Member

    Messages:
    43
    Location:
    Pittsburgh
    well catrafter had the idea to take out both channel board ( dam should of thought of that ), one of them has surly had some work done on it ( right side board ), could this be the good board that's giving headphone sound ?, or at least better than the other.

    The left board you pretty much called if i reading this right, we have 2 shorts H715 B+C short sound, all so H716 E+C is giving short sound too. All so the resistor R742 (oops) is blown.

    H005\6 ?, were they at ?.

    Thank You.

    Ooh a pic :p
    [​IMG]
     
    Last edited: Apr 30, 2018
    mbz likes this.
  14. mbz

    mbz AK Subscriber Subscriber

    Messages:
    2,101
    Location:
    Melbourne, Victoria
    Not familiar with marantz receivers.
    These are typically "tin cans" and will be heat sink mounted.
    There will be 8, 2 for each channel, should be easy to spot.

    R746 blown, maybe check,
    H720 & H722
    H712
    H728 (diode chain, typically heat sink mounted)
     
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  15. petehall347

    petehall347 the brandy coffee man Subscriber

    Messages:
    27,627
    Location:
    uk.. the middle bit
    looks like r742 blown ..biasing circuit needs looking at first .
    shorted outputs could also cause this .
    also check outputs are installed in correct order .
     
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  16. AsRock

    AsRock New Member

    Messages:
    43
    Location:
    Pittsburgh
    Doing pretty dam well so far :).

    will check those over the next day or so, but those tin cans are partly in the picture at the top.

    Yeah that was my bad, i had put 746 ^^.

    Yeah only way i be able tell is by by looking at the wired on either side to see if it's the same.
     

     

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  17. petehall347

    petehall347 the brandy coffee man Subscriber

    Messages:
    27,627
    Location:
    uk.. the middle bit
    carry on searching .see what you find .
     
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  18. AsRock

    AsRock New Member

    Messages:
    43
    Location:
    Pittsburgh
    Well sorry for the lack of details, i thought if i am going do this i should pick up a DCA55, well i got it today and got around in testing the main transistors and found 2 failed ones, Here's the list of transistors and are listed top to bottom.

    Right Side
    SJ2517
    SJ2518
    2SC1403
    A475
    All tested good with no leaking with 33-100 gain.

    Left Side
    2SC1403 ( Failed )
    2SA745 ( Failed )
    SJ2517
    SJ2518

    Left Side
    B357 (H715)
    B527 (H716)
    R742 ( failed )

    Between H730 & H718 there is a working but partly burned resistor.


    Be checking the sound boards and maybe the power board tomorrow.
     
  19. AsRock

    AsRock New Member

    Messages:
    43
    Location:
    Pittsburgh
    Well, compared both sound boards and they seem to match except for the 3 parts that in the last post that were said to be faulty.

    H717\18 H721\22 short sound from E+B, took them out and tested ok.

    H707\8 H709\10 out of the 4on the board one showed up as a darlington , the other 3 did not and all measured pretty much the same.

    Just started on the PSU section and found a issue(s).

    H806 was in the wrong way around ( according to Service manual and board ) and all so found that H805 had the same transistor as H806\7 and not a 2SA945 which i need help on if it's a suitable replacement part or some thing that should not of been added. From what i can tell it is, All tested good.

    Diodes tested good as far as i can tell.

    Elec cap have one of them showing up a 450uf when it should be 220uf on the power board.
     
  20. petehall347

    petehall347 the brandy coffee man Subscriber

    Messages:
    27,627
    Location:
    uk.. the middle bit
    H805 should still work unless i missed something ..

    H717\18 H721\22 short sound from E+B, took them out and tested ok. ...did you test the output transistors yet ?

    Elec cap have one of them showing up a 450uf when it should be 220uf on the power board. ...needs replacing ..unless you tested in circuit ? if so you are likely measuring a 470uf with it
     
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