SX-5580 SX-1050 SMOKING HOT...ON POWER UP

Discussion in 'Pioneer Audio' started by r887661, Sep 10, 2017.

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  1. r887661

    r887661 AK Subscriber Subscriber

    Messages:
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    I recently aquired a non working SX-5580...it really was a disgusting mess. I wanted to be sure it was 100% clean so that I could examine everything visually before powering up.

    It cleaned up beautifully and all my inspection showed was missing jumpers, missing main fuse center fuse holder and pcb AWR-104 four mounting posts all broken.

    I reseated the board (all fuses rated properly and tested good), fitted jumpers and a new fuse holder with 10a fuse and voltage selector at 120v

    On powering up the surge protector AWX-098 started to smoke. I immediately shut off power.

    I throw myself at your mercy requesting some help and advice from my knowledgeable peers....thank you..
     
    Last edited: Sep 13, 2017
  2. larryderouin

    larryderouin Do I get Food, Med's, or more gear this Month? Subscriber

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    From what I understand about the circuit, there is a special resistor, a temperature sensitive switch, a cap and the relay to send power downstream. Page 21 of the Service Manual addresses the operation and what parts are used. When the power switch is thrown the resistor heats up, and the cap charges. As the resistor heats up the cap charges, and the temp sensitive switch closes, powering the relay and shorting out the resistor.
    That's my understanding of it, but it may be slightly off or even completely wrong. The end result in happy times is that the toroidal transformer fires up and makes reasonable voltage for the various circuits and you get music. In not so happy times, the surge circuit is faulty and can smoke, or just no work at all. Smoke is indicative of a few things in no particular order. 1.) Lots of DUST inside the enclosure burning off. 2.) Overloading of the surge circuit resistor due to a short circuit in the unit (most likely in the output's to make that kind of hi amperage )short. 3.) a dead short in the primary leads to or the secondary leads from the toroidal transformer. 4.) Pinched or torn insulation on leads to/from the power switch causing a short circuit.

    Parts are available, but some modifications are needed. Search "sx-1050 Surge circuit" or variations of that in google. Look for Audiokarma links and read all of them. For now, don't do anything other than cleaning and or disassembly enough to expose the circuit. One of th more experienced guys familiar with the 1050 will be along soon (I hope!). You might edit the title and add "/sx-1050" after SX-5580. Not a lot of 5580's around and most guys aren't familiar with them. Pictures of the unit in question (both outside and inside (close up's of the power supply area)) help us a lot. Keeps everyone on the same page.

    Double check the Surge Protection circuit board number on your 5580. In the 1050 manual it's a AWX-098. 1050 manual here
     
  3. tsd71

    tsd71 RIP Tom Petty Subscriber

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    Check your output transistors, that thermal fuse can blow up if an output is smoked. Worked on a 1250 with the same issue.
     
  4. larryderouin

    larryderouin Do I get Food, Med's, or more gear this Month? Subscriber

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    Just above the original post on the right there is wording to the effect of "edit thread". Click on that and then click on "edit title". Do the edit and save.
     
  5. LesE

    LesE 110284 Subscriber

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    First thing I'd do is build a DBT if you don't already have one and perform all further tests using a 100W bulb to avoid further damage.

    Is the smoke coming from the 3.3 ohm 20W ballast resistor or elsewhere? If the resistor is getting too hot, the microtemp switch should blow to prevent fire.

    Is the bypass relay activating shortly after power on? This relay should activate and bypass the ballast resistor and microtemp switch. If the relay isn't operating, the resistor will get very hot until the microtemp blows. I believe the microtemp needs to be in direct contact with the resistor body in order to protect it properly.

    Les.
     
  6. zebulon1

    zebulon1 Cleaned up the shop and half finished sets. Subscriber

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    You might need this micro temp fuse.
    Better check it.
    https://www.parts-express.com/nte-8108-thermal-cut-off-109c-229f--nte8108
    Special soldering techniques are required. Soldering can cause it to open.

    You have some work ahead of you on this one.
    Many parts to check and things to know.
    You could easily cause more damage if unsure of the procedures.
    If you plan on repairing this yourself:
    Build that DBT before doing anything else.
     
  7. r887661

    r887661 AK Subscriber Subscriber

    Messages:
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    Location:
    Ludington, Michigan
     
  8. r887661

    r887661 AK Subscriber Subscriber

    Messages:
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    Location:
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    I will build a DBT before I go any further. The smoke is most deffinitely coming from the 3.3 ohm 20W resistor ACN-006
    The bypass relay does not activate. I am sure you mean S2 ASR-015
    The micro temp AEX-001 is in direct contact with the big resistor
    There is the possibility that I am shutting off power to early if we are expecting the relay to act after more than two seconds.
     
    Last edited: Sep 13, 2017
  9. r887661

    r887661 AK Subscriber Subscriber

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    Location:
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    DBT will be put together tonight.
    I have a spare Surge Current Protector Assy. AWX-098 and a spare relay ASR-015 I bought these after my first round of investigation
     
    Last edited: Sep 13, 2017
  10. zebulon1

    zebulon1 Cleaned up the shop and half finished sets. Subscriber

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    The in rush is a split second then the relay, so close to the click of the power switch. It happens in an ignasecond.
    The second relay is the protection and you can usally hear this one. Its about 5 seconds after switching the power on.

    The DBT is a tool you will need if you plan on repairing this set.
    There could be a few problems but the outputs and associated circuit are the biggest suspects.
    The micro fuse should of blown (opened) with the resistor smoking. Visually check that circuit and the micro fuse with a DMM first. Someone could of bypassed the in-rush protection.
    In less something else is smoking. Images of the area you see and know is smoking would be helpful.
    Second, check the outputs as mentioned. There's no way to isolate them and run the set. The outputs are wired connected to the unregulated supply, even when the amp boards are unplugged.
    You'll have to remove them (outputs) and check each one separately.
    Take notes and pictures.

    On you first post in the thread there's a link called "Thread tools" at the top right corner of the post. Click on that and you'll see the title edit selection.

    inrush.PNG
     
    Last edited: Sep 13, 2017
  11. r887661

    r887661 AK Subscriber Subscriber

    Messages:
    97
    Location:
    Ludington, Michigan
    I have my shopping list together for a trip to the hardware store to get the parts for a DBT. I'll put it together tonight but I am moving house this weekend so doubt I'll get my hands into the 5580 until next week. Meantime please keep sending me your advice because I know I can get this fixed with your help.

    Meantime, some before and after pictures cleaning the beast...after ensuring all caps etc drained down...
    1..Blow off gently with compressed air
    2..Brush all over, many times, with Simple Green
    3..Hose off gently for 20 minutes
    4..Drench in at least 2 gallons of distilled water
    5..Leave with ceramic heater fan about 3 feet away for seven days turning once a day
     

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    Last edited: Sep 13, 2017
  12. Blue Shadow

    Blue Shadow I gotta get me a new title

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    This is a Red Banner Subscriber feature.
     
  13. r887661

    r887661 AK Subscriber Subscriber

    Messages:
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    Location:
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    I have a "Thread Tool" button but when I press it all I get is "Add Poll"...no reference anywhere to editing...stumped!!! Ah, Red Banner Subscriber...I see...let me fix right now...
     
    Last edited: Sep 13, 2017
  14. r887661

    r887661 AK Subscriber Subscriber

    Messages:
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    Location:
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    [QUOTE="zebulon1, post: 10854678, member: 96897"
    Attached is an image of exactly where it smokes...it is pretty instant...
     

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  15. r887661

    r887661 AK Subscriber Subscriber

    Messages:
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    OK, I am now a Bona Fide AK member, all dues paid...an honest man at last!!!
     
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  16. Blue Shadow

    Blue Shadow I gotta get me a new title

    Messages:
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    And we get another one to join. Nice update on the title. Smoked!!!

    I've BTDT, will do it again.

    Fortunately, the OM on the web for the 5580/1050 twins is for the 5580.
     
  17. r887661

    r887661 AK Subscriber Subscriber

    Messages:
    97
    Location:
    Ludington, Michigan
    I have the Service and Operators Manual all downloaded and referenced to the parts I need to focus on.

    I'll get this weekend's house move out of the way, get the Mcintosh MR78 hooked up to the Mitsubishi DA A 15DC amp and Snell CV3 speakers and I'll be in hog heaven ready to makes sparks fly, well not literally I hope...Going to make that DBT tonight...
     
  18. larryderouin

    larryderouin Do I get Food, Med's, or more gear this Month? Subscriber

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    Another option for a DBT is to use a 3way socket and install a 50-100-150 Watt 3 way bulb. The 1050/5580 draws 870W max (including the 500W from the accessory plugs) so about 370W running wide open. A 150W bulb might be more appropriate here due to the soft start circuit, as a 100W would starve the circuit too much and it won't complete the changeover and possibly burn up the soft start components.
     
  19. r887661

    r887661 AK Subscriber Subscriber

    Messages:
    97
    Location:
    Ludington, Michigan
    I will get both 100w and 150w lamps....
     
  20. larryderouin

    larryderouin Do I get Food, Med's, or more gear this Month? Subscriber

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    Get the ones that say "heavy duty service". Those are generally not used in the house, but in a garage or shop environment.
     

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