Onkyo M-504 help needed.

Dabutcher
Dabutcher Posts: 2,596
in Electronics
Bought this a couple of months ago. Meters lit up when I bought it. Just hooked it up to my two channel set up. No sound. Opened up. Super clean unit. No fuse in one fuse holder? I wonder why no fuse in there? Such kool meters! Thanks for any help. Peace. Dxo9ns9cf13gb.jpeg
xmaeztsrdhby.jpeg
MIT Magnum MH-750, Monster HTS 5100MKII, Sony 77" Class - A80CJ Series - 4K UHD OLED,PS4, Def Tech 15” sub,LSIM 706c, Sunfire Signature Grand 425 x 4,Parasound hca 120, LSiM 702 x 4, Oppo 103D, SDA SRS 1.2, Pioneer Elite SC63 , Pioneer Elite BDP-05 “Why did you get married if you wanted big speakers?”
· Share on FacebookShare on Twitter

Comments

  • F1nut
    F1nut Posts: 50,592
    Put a fuse in it.
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."

    President of Club Polk

    · Share on FacebookShare on Twitter
  • Dabutcher
    Dabutcher Posts: 2,596
    Thanks ,my brother. Next step I was going to make. Wish me luck. Peace. D
    MIT Magnum MH-750, Monster HTS 5100MKII, Sony 77" Class - A80CJ Series - 4K UHD OLED,PS4, Def Tech 15” sub,LSIM 706c, Sunfire Signature Grand 425 x 4,Parasound hca 120, LSiM 702 x 4, Oppo 103D, SDA SRS 1.2, Pioneer Elite SC63 , Pioneer Elite BDP-05 “Why did you get married if you wanted big speakers?”
    · Share on FacebookShare on Twitter
  • ken brydson
    ken brydson Posts: 8,762
    Dabutcher wrote: »
    Thanks ,my brother. Next step I was going to make. Wish me luck. Peace. D

    Have someone hold your beer and stand back a ways...
    · Share on FacebookShare on Twitter
  • Dabutcher
    Dabutcher Posts: 2,596
    Fuse blew as soon as I turned it on.
    MIT Magnum MH-750, Monster HTS 5100MKII, Sony 77" Class - A80CJ Series - 4K UHD OLED,PS4, Def Tech 15” sub,LSIM 706c, Sunfire Signature Grand 425 x 4,Parasound hca 120, LSiM 702 x 4, Oppo 103D, SDA SRS 1.2, Pioneer Elite SC63 , Pioneer Elite BDP-05 “Why did you get married if you wanted big speakers?”
    · Share on FacebookShare on Twitter
  • erniejade
    erniejade Posts: 6,321
    I used to have one. Depending on $ to fix it, I thought they were a good sounding amp. I ran mine for years and sold it when I got a Sunfire.
    Klipsch The Nines, Audioquest Thunderbird Interconnect, Innuos Zen MK3 W4S recovery, Revolution Audio Labs USB & Ethernet, Border Patrol SE-I, Audioquest Niagara 5000 & Thunder, Cullen Crossover II PC's.
    · Share on FacebookShare on Twitter
  • tonyp063
    tonyp063 Posts: 1,085
    hifiengine has the service manual with wiring diagram.
    https://www.hifiengine.com/manual_library/onkyo/m-504.shtml

    According to it, that fuse is on the 120V side before the power transformer. Typically (and not always) a short in the power switch would cause what you are seeing.
    At least, that's where I would look first
    · Share on FacebookShare on Twitter
  • Dabutcher
    Dabutcher Posts: 2,596
    I have a second one with one side that has gone out. Just been sitting for years now. I could use it for parts. When you say power switch, do you mean the button I push to power on? As always thanks for all your help. D
    MIT Magnum MH-750, Monster HTS 5100MKII, Sony 77" Class - A80CJ Series - 4K UHD OLED,PS4, Def Tech 15” sub,LSIM 706c, Sunfire Signature Grand 425 x 4,Parasound hca 120, LSiM 702 x 4, Oppo 103D, SDA SRS 1.2, Pioneer Elite SC63 , Pioneer Elite BDP-05 “Why did you get married if you wanted big speakers?”
    · Share on FacebookShare on Twitter
  • tonyp063
    tonyp063 Posts: 1,085
    Yes.
    You'll also want to check the power transformers for continuity & shorts.
    The aforementioned manual has a good schematic & so troubleshooting tests.
    · Share on FacebookShare on Twitter
  • DaveHo
    DaveHo Posts: 3,531
    He shows a pic with the meters lit up. Wouldn't that rule out the transformer & power switch?
    · Share on FacebookShare on Twitter
  • tonyp063
    tonyp063 Posts: 1,085
    If I'm reading the schematic right (and there's no guarantee of that because I have old eyes) no.
    It looks like each PS transformer is fused separately on different switch legs. The meters get their light power from only one of the transformers, so the other leg of the circuit is the suspect one.
    See the bottom of page 9

    Also look at the precaution on page 3 to do an insulation test measurement.
    unplugged. both fuses in.
    then run a meter between each plug leg & chassis ground with the switch on.
    Should see over 10M ohms
    · Share on FacebookShare on Twitter
  • daddyjt
    daddyjt Posts: 2,521
    What's your electronics knowledge? Do you own a DMM? If so, locate the output transistors and check for leg-to-leg and leg-to-ground shorts.
    "Conservative Libertarians love the country, progressive leftists love the government." - Andrew Wilkow


    “Human beings are born with different capacities. If they are free, they are not equal. And if they are equal, they are not free.”
    ― Aleksandr Solzhenitsyn

    · Share on FacebookShare on Twitter
  • ken brydson
    ken brydson Posts: 8,762
    daddyjt wrote: »
    and check for leg-to-leg and leg-to-ground shorts.

    Leave Joey out of this...

    · Share on FacebookShare on Twitter
  • Unknown
    Unknown
    edited January 2017
    This content has been removed.
  • BruceHolcomb65
    BruceHolcomb65 Posts: 2
    Not sure if you’ve fixed your problem but you probably have a shorted or grounded transistor in your left channel.
    · Share on FacebookShare on Twitter