How do I tell which diode to use if the number is worn off?

Discussion in 'General Electronics Chat' started by W123, Apr 27, 2011.

  1. W123

    Thread Starter New Member

    Apr 27, 2011
    4
    0
    Ive got a Ampeg V-4 guitar amp that the last owner rigged the crap out of so the list of parts to swap is growing. Right now Im just swapping things that are visually degraded (Exploded resistors, juicy caps, stuff that is either worn out or will wear out soon). Ill get deeper into it later.

    Sooo, theres this diode which has somehow oozed junk and I want to swap it but the number is worn off. The schematic says F-10 right under the labeling (D5). There really isnt anything else to go off of. What now?
     
  2. BillO

    Well-Known Member

    Nov 24, 2008
    985
    136
    Try to analyze the circuit to determine what the diode was doing. That should give you some clue.
     
  3. HallMark

    Member

    Apr 3, 2011
    89
    5
    As the number is erased it may be diode to drop 0.3 or 0.7 Volt or it may be Schottkey diode too. :(
     
  4. marshallf3

    Well-Known Member

    Jul 26, 2010
    2,358
    201
    The company's still in business, write and ask. They may even have a full schematic &/or service manual you can download r they can e-mail to you as an attachment. http://www.ampeg.com/
     
  5. W123

    Thread Starter New Member

    Apr 27, 2011
    4
    0
    I do have the schematic. Ampeg was nice enough to glue one on the inside when it was made. All it says is F-10 by the diode. Bah. I havent actually pulled it off the board yet. The front is worn off, maybe the back side of it has enough left to tell. If its got pieces of numbers that match the ones around it then Ill just use those and pray. Its kinda a oneshot on the schematic so there arent any identical sections to say "Hey theyre doing the same thing here, its probably the same one!"

    Thanks.
     
  6. marshallf3

    Well-Known Member

    Jul 26, 2010
    2,358
    201
    I still think sending them an e-mail is the best procedure. If it turns out to be a zener or something in the bias circuitry of the amp you could blow the whole thing up just guessing on the diode.
     
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