faulty Arcam amplifier

Discussion in 'Electricians' Talk' started by robertpstubbs, Jun 12, 2018.

  1. robertpstubbs

    robertpstubbs Member

    I have a 30yo Arcam Alpha amp. Some years ago the internal fuse (500mAT ?) (not the speaker fuses) blew. I replaced it and it immediately blew again.

    I don't know much about amps. Any ideas what to look at?
     
  2. KIAB

    KIAB Well-Known Member

    Last edited: Jun 12, 2018
  3. Bob Rathbone

    Bob Rathbone Well-Known Member

    What type of power supply is in the amplifier, if it is a switching PSU then that is faulty, if it's a heavyweight low frequency transformer, then the fault will probably be in the bridge rectifier or smoothing capacitors. Depends how much you want to spend on fixing it.
     
  4. Bob Rathbone

    Bob Rathbone Well-Known Member

    290 years Kiab? did they have electricity back then? :)
     
  5. DIY womble

    DIY womble Active Member

    When you say the fuse immediately blew , how much time do you mean
     
  6. KIAB

    KIAB Well-Known Member

    :oops::oops::oops::rolleyes:

    Slight typo,bad habit using this keyboard,I can accidently delete sentences/words.:mad:
     
  7. robertpstubbs

    robertpstubbs Member

    IIRC within a second or two.
     
  8. KIAB

    KIAB Well-Known Member

    Probably a failing capacitor,outside chance it's a rectifier dying.
     
  9. DIY womble

    DIY womble Active Member

    You could also check your transformer coil for earth leakage / short ,
     
    Dr Bodgit likes this.
  10. Dr Bodgit

    Dr Bodgit Well-Known Member

    I had the same issue on my Muse 300W monoblocks, took it to Raphael @ http://www.sutamps.com/repairs-servicing/ and he fixed it, turned out to be a shorted secondary winding on one the of transformers. Initially they looked into having a transformer built from scratch, but then found the company that made the originals, had office in Wales so called them and had a couple of new transformers shipped. He also checked the many MOSFET transistors and replaced one that was out of spec.

    Bad news is that it looks like Raphael has moved to Norfolk and is not taking on new business at the moment...might be worth contacting them if you're over that way.
     
  11. KIAB

    KIAB Well-Known Member

    Used them some years ago, they fixed my buzzy marshall amp,great service.:)
     
    Dr Bodgit likes this.
  12. Dr Bodgit

    Dr Bodgit Well-Known Member

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