Amplifier burned, please help to ID parts

Discussion in 'Electronics Repair' started by Keks, Feb 16, 2017.

  1. Keks

    Keks

    Joined:
    Feb 16, 2017
    Messages:
    10
    Likes Received:
    4
    This little unit in my amplifier burned, I would like to try and fix it myself, but not sure what these little blue guys are. I thought they are caps but not sure what kind and what to replace them with. Any help would be greatly appreciated

    20170129_181710.jpg

    20170129_181715.jpg


    20170214_064204.jpg

    20170214_064107.jpg
     
    Last edited by a moderator: Feb 17, 2017
    Keks, Feb 16, 2017
    #1
    1. Advertisements

  2. Keks

    davenn Moderator

    Joined:
    Sep 5, 2009
    Messages:
    11,928
    Likes Received:
    1,367
    Location:
    Sydney, Australia
    Hi Keks
    welcome to EP :)

    yes they are 0.1uF caps probably rated at ~ 100V

    the bridge rectifier behind them could be suspect as well

    Dave
     
    davenn, Feb 17, 2017
    #2
    1. Advertisements

  3. Keks

    Keks

    Joined:
    Feb 16, 2017
    Messages:
    10
    Likes Received:
    4
    Thank you, Dave.
    Would you know if they are polarised? Or does it matter at all? That little arrow confuses me.
    I well check the rectifier as well, thanks again.
     
    Keks, Feb 17, 2017
    #3
    davenn likes this.
  4. Keks

    davenn Moderator

    Joined:
    Sep 5, 2009
    Messages:
    11,928
    Likes Received:
    1,367
    Location:
    Sydney, Australia
    no, they wont be polarised
     
    davenn, Feb 17, 2017
    #4
  5. Keks

    73's de Edd

    Joined:
    Aug 21, 2015
    Messages:
    1,579
    Likes Received:
    503
    Location:
    Texas
    Sir Keks . . . . . . . .

    As Davenn said . . . . that FULL WAVE RECTIFIER BLOCK should be bad.

    that set of ceramic capacitors are as badly burnt as I have seen.

    The way they vaporized I would be wanting to use a much higher rating than 100V . . . . .more likely some X2 or Y2 ceramic units that are voltage rated well-well-well above 100V.

    That left corner seems to have a heat shrinked, hidden connector . . . . is that 230 AC in ?
    What I am seeing is that you are from Ireland and that would be 230-40 AC power

    The center rear board seems to have two pairs of 5 way binding posts on it SPEAKER OUTPUT CONNECTORS ?
    Plus it seems like some HUGE power connectors beside them.

    Is this possibly a unit that can be both AC line powered or 12 VDC powered.

    A cursory look tends to suggest a linear power supply using that toroid . . .but things MIGHT be different, if this unit also works with 12VC in .

    What are the voltage spec and capacitance ratings on those centrally located two large, black canned electrolytics.

    All that I can see are two POWER semiconductors . . . . . that are using that HUGE heat sink . . . . are any units mounted on its other / unviewable end ?

    What is the BRAND and model of this unit . . . . . and it probably will torn out be one that we can find no info on ?

    73s de Edd
     
    Last edited by a moderator: Feb 17, 2017
    73's de Edd, Feb 17, 2017
    #5
  6. Keks

    davenn Moderator

    Joined:
    Sep 5, 2009
    Messages:
    11,928
    Likes Received:
    1,367
    Location:
    Sydney, Australia
    depends on why they failed .... seeing the type of failure, it is most likely due to a large power line spike rather than from normal operation at the standard circuit voltage
     
    davenn, Feb 17, 2017
    #6
  7. Keks

    davenn Moderator

    Joined:
    Sep 5, 2009
    Messages:
    11,928
    Likes Received:
    1,367
    Location:
    Sydney, Australia
    I see no sign of any DC input

    @Keks can you please take a photo of the front panel of the amp
     
    davenn, Feb 17, 2017
    #7
  8. Keks

    Keks

    Joined:
    Feb 16, 2017
    Messages:
    10
    Likes Received:
    4
    Here are more photos, I could not find any schematics for this online. Maybe you will be more lucky)

    20170218_080333.jpg 20170218_081153.jpg 20170218_081429.jpg
     

    Attached Files:

    Last edited by a moderator: Feb 18, 2017
    Keks, Feb 18, 2017
    #8
  9. Keks

    davenn Moderator

    Joined:
    Sep 5, 2009
    Messages:
    11,928
    Likes Received:
    1,367
    Location:
    Sydney, Australia
    Awesome, thanks .... confirms my thoughts that there is no DC input. I was quite familiar with that with the professional amplifiers I used to install/repair
    As they were often in public areas eg shopping centres, they supplied not only background music but also paging, and evacuation alert sounds.
    As a result they had to be able to run off battery in case the mains power failed

    OK you need to replace those 4 caps and bridge rectifier for a start and then we can go from there

    Ohhh ... you haven't answered Edd's question about what all is bolted to that big heatsink ?
     
    davenn, Feb 18, 2017
    #9
  10. Keks

    duke37

    Joined:
    Jan 9, 2011
    Messages:
    4,488
    Likes Received:
    539
    Location:
    Derbyshire. UK
    What is the black grot on the transformer. If it is some pitch droped on the winding, then OK. Of it is a due to a shorted turn, then you will need a new transformer.
    Disconnect the transformer output connections and check for power.
     
    duke37, Feb 18, 2017
    #10
  11. Keks

    davenn Moderator

    Joined:
    Sep 5, 2009
    Messages:
    11,928
    Likes Received:
    1,367
    Location:
    Sydney, Australia
    Look at the earlier pic of the whole transformer .... does look like it was filled with some sort of resin and that on the outside
    edge is just a few spill drops
     
    davenn, Feb 18, 2017
    #11
  12. Keks

    Keks

    Joined:
    Feb 16, 2017
    Messages:
    10
    Likes Received:
    4
    Hi, Edd.

    You were right, there are more of them on the other side.

    20170218_150032.jpg
     
    Keks, Feb 18, 2017
    #12
  13. Keks

    Keks

    Joined:
    Feb 16, 2017
    Messages:
    10
    Likes Received:
    4
    I was looking at that as well, it is some resin spilled, just like Davenn thought.
     
    Last edited by a moderator: Feb 18, 2017
    Keks, Feb 18, 2017
    #13
  14. Keks

    Keks

    Joined:
    Feb 16, 2017
    Messages:
    10
    Likes Received:
    4
    Will I use .1uf caps or bigger ones will be better? Any suggestions on bridge rectifier specs?
    Sorry I am verry new to this and need to ask the things that might be obvious.
     
    Keks, Feb 19, 2017
    #14
  15. Keks

    davenn Moderator

    Joined:
    Sep 5, 2009
    Messages:
    11,928
    Likes Received:
    1,367
    Location:
    Sydney, Australia
    no, just 0.1 uF. the size of them and their colour indicate that they may be rated at 1kV ( this is much higher than they would be running at) but that is OK

    an educated guess, probably going top be rated at around 45 Amps ( more info on the circuit would help with that)

    a schematic or service manual would be extremely helpful
     
    davenn, Feb 19, 2017
    #15
    bushtech likes this.
  16. Keks

    73's de Edd

    Joined:
    Aug 21, 2015
    Messages:
    1,579
    Likes Received:
    503
    Location:
    Texas
    Sir Keks . . . . . .

    I now see that the principal power transistotrs* / or / FETS * are merely those two transistors per channel, that are mounted on the bottom of the heat sink . . . . with a couple of ancillary heat sensors also being thermally tied in.

    Pass us the numbers on them* so that we can see just how much OOOOMPH that they are capable of . . .just in case the end result is that they were also affected.
    Somewhere on that Full wave bridge housing, I would expect some ID numbers on it also.
    As Davenn said ... your photo also revealed that the unit is solely AC line powered and that the end lowered supply voltages are being 44VAC centertapped and 68VAC centertapped..

    Have you either diode mode tested or ohmmed out the four power diode junctions within the FWB to see how many sections are dead shorted ?
    Also was the AC line fuse badly blackened within its envelope ?
    Your photo of the LARGE main supply electrolytics failed to show their Capacitance and Voltage specs
    The visible M0003 numbering does not fly.
    Also I might just barely see one end cap of what possibly might be the line fuse . . . . . unless it has been replaced, it seems to be a clean slow/delay rated unit.

    73s de Edd
     
    Last edited by a moderator: Feb 20, 2017
    73's de Edd, Feb 20, 2017
    #16
  17. Keks

    Keks

    Joined:
    Feb 16, 2017
    Messages:
    10
    Likes Received:
    4
    I found some schematics. Hope this will help.
    If i am reading it right large caps are 10 000/50, Diodes on bridge rectifier are IN4004.
    AC fuses were not affected.
    I did not test diodes. I will will do a little search on how to do it and will give it a try. Bridge rectifier is a solid unit, I think it can not be fixed and will have to be replaced. Please correct me if i am wrong.
     

    Attached Files:

    • 1.pdf
      File size:
      455.8 KB
      Views:
      30
    • 2.pdf
      File size:
      89.2 KB
      Views:
      26
    • 3.pdf
      File size:
      475.9 KB
      Views:
      26
    Keks, Feb 22, 2017
    #17
  18. Keks

    davenn Moderator

    Joined:
    Sep 5, 2009
    Messages:
    11,928
    Likes Received:
    1,367
    Location:
    Sydney, Australia
    Ok that is a great help :)

    unfortunately tho, your parts list didn't include the capacitors use ..... the schematic is only showing 2 of the 4 blue caps that is in your pic


    there are 2 bridge rectifiers .... a low current one using 4 separate 1N4004 's .... this IS NOT the one in your pic with the cooked caps
    the single item bridge rectifier in that pic of yours in the upper of the 2 in the schematic ... the KBPC804 ... it's an 8 Amp 400V rated diode

    looks like this amplifier has no way of generating 2000 W (that rating is just a joke) with only 4 output transistors and an 8 amp rectifier
     
    davenn, Feb 23, 2017
    #18
  19. Keks

    Keks

    Joined:
    Feb 16, 2017
    Messages:
    10
    Likes Received:
    4
    Thank you for the help guys, it is great to have support. I ordered 50amp bridge rectifier and .1uf 1kv caps. Will post an update when get them in. Nice weekend to everyone.
     
    Keks, Mar 3, 2017
    #19
    davenn likes this.
  20. Keks

    davenn Moderator

    Joined:
    Sep 5, 2009
    Messages:
    11,928
    Likes Received:
    1,367
    Location:
    Sydney, Australia
    look forward to seeing how you get on
    just be aware that what ever blew those caps ( a big power surge maybe) may have done other damage

    I would power up the PSU section on its own for a start ... that is, have the rest of the main amp board disconnected
     
    Last edited: Mar 4, 2017
    davenn, Mar 3, 2017
    #20
    1. Advertisements

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Similar Threads
  1. b
    Replies:
    1
    Views:
    1,572
  2. Roy and Rosa

    Help ID capacitor on Magnavox tv 25B800. Burned

    Roy and Rosa, Dec 6, 2004, in forum: Electronic Repair
    Replies:
    1
    Views:
    634
  3. techdrive

    Crest CA12 Power Amplifier Input PCB - parts ID help

    techdrive, Mar 1, 2005, in forum: Electronic Repair
    Replies:
    1
    Views:
    1,512
    Shoreline Electronics
    Mar 2, 2005
  4. Alvin

    help please burned motherboard for a ray

    Alvin, Mar 17, 2005, in forum: Electronic Repair
    Replies:
    1
    Views:
    509
  5. jishak
    Replies:
    4
    Views:
    417
    Harald Kapp
    Nov 1, 2016
  6. Tasin
    Replies:
    23
    Views:
    375
    Harald Kapp
    Dec 13, 2016
  7. Arthur Sliter

    Please Help! Need to ID an IC!!

    Arthur Sliter, Dec 24, 2016, in forum: Electronics Repair
    Replies:
    1
    Views:
    108
    73's de Edd
    Dec 24, 2016
  8. MartyMcFly
    Replies:
    2
    Views:
    155
    KMoffett
    Jan 2, 2017
Loading...