Results 1 to 7 of 7

Thread: Behringer EP2500 +\- 15V rails missing

  1. #1
    Senior Member
    Join Date
    Dec 2011
    Location
    Pretoria, South Africa
    Posts
    175

    Behringer EP2500 +\- 15V rails missing

    Hi there. I have this amp for repair. The 15 rails needed to run Ic4&6 are missing. The zener diodes are fine. Dropper resistors R47,34,49,55,62,65,64,61 are heating up. I have already replaced ic4&6. Same problem.
    ENZO, maybe you have seen this before? Any ideas?

  2. #2
    Senior Member
    Join Date
    Dec 2011
    Location
    Pretoria, South Africa
    Posts
    175
    Cmon Folks!!!

  3. #3
    Old Timer
    Join Date
    Oct 2007
    Location
    Buenos Aires, Argentina
    Posts
    4,568
    Post the schematic.
    Otherwise .... IC4/6 , R47 to 61, etc. mean nothing.
    Do your homework: what's used for the +/-15V supply?
    Dropping from higher rails through power resistors and regulating with Zeners?
    Dedicated low voltage PSU further regulated with LM7x15?
    A combination of both?
    What do those rails feed?

    In a metallic screechy voice: "com-pu-ter-needs-more-da-ta"
    Juan Manuel Fahey

  4. #4
    Supporting Member Jazz P Bass's Avatar
    Join Date
    Dec 2008
    Location
    Wernersville, PA
    Posts
    5,447
    Here is the schematic.
    Attached Files Attached Files

  5. #5
    Senior Member
    Join Date
    Dec 2011
    Location
    Pretoria, South Africa
    Posts
    175
    Thanx for all the replies guys. I managed to track the fault down.. It was the transconductance amplifier chip that was soft shorted, pulling the 15V rails down.

  6. #6
    Supporting Member Jazz P Bass's Avatar
    Join Date
    Dec 2008
    Location
    Wernersville, PA
    Posts
    5,447
    So it was the + - 15 "B" supply.

  7. #7
    Senior Member
    Join Date
    Dec 2011
    Location
    Pretoria, South Africa
    Posts
    175
    yep. indeed!

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Hot rails
    By Jan666 in forum Pickup Makers
    Replies: 3
    Last Post: 04-29-2012, 08:36 PM
  2. Peavey phantom power: +15V?
    By Rhodesplyr in forum Music Electronics
    Replies: 5
    Last Post: 01-28-2011, 08:41 AM
  3. Weird DSL +/- 15v supply problem.
    By jcmjmp in forum Maintenance, Troubleshooting & Repair
    Replies: 10
    Last Post: 10-01-2009, 03:48 AM
  4. PWM amp with modulated rails
    By earthtonesaudio in forum Theory & Design
    Replies: 4
    Last Post: 09-30-2009, 01:51 PM
  5. Replies: 0
    Last Post: 12-03-2008, 09:10 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •