Results 1 to 4 of 4

Thread: Jbl se401 /402 amp energizer transformer problem

  1. #1
    Senior Member
    Join Date
    Mar 2012
    Location
    TN
    Posts
    409

    Jbl se401 /402 amp energizer transformer problem

    Does anyone know what a good replacement for the Jbl se402 transformer is? An original would be nice but is there a possible altec / peerless match that I could substitute with? Also is install easy? My tech at my local audio repair could not fix it and diagnosed it as a bad transformer. One channel work and the other is low output and buzzing.

  2. #2
    RE: Member when? subwoof's Avatar
    Join Date
    Aug 2003
    Location
    fingerlakes region, NY
    Posts
    1,898

    not transformer

    If ANYTHING works the transformer is fine...get a second opinion..

    ALL electronics that age need to have the power supply electrolytics replaced - do that FIRST then diagnose...

    sub

  3. #3
    Junior Member
    Join Date
    Apr 2015
    Location
    Las Vegas NV
    Posts
    12

    Which Transformer - There Are 3? - This Is Not A Transformer Problem

    Quote Originally Posted by script56 View Post
    Does anyone know what a good replacement for the Jbl se402 transformer is? An original would be nice but is there a possible altec / peerless match that I could substitute with? Also is install easy? My tech at my local audio repair could not fix it and diagnosed it as a bad transformer. One channel work and the other is low output and buzzing.
    You said "One channel works". Apparently, your "tech at my local audio repair" failed to tell you that the power transformer is good if any channel works.

    Since "the other is low output and buzzing", this is not a transformer problem either. I had the same type of problem. A full replacement of all of the original electrolytic capacitors with new Vishay Sprague 138 AML (on the circuit boards) and Nichicon LGY1J472MELA50 (in the power supply) got my SE401 to work 'as good as new', which was OK.

  4. #4
    Junior Member
    Join Date
    Apr 2015
    Location
    Las Vegas NV
    Posts
    12

    An Apology - When Disaster Strikes The JBL SE401 Protection Circuit Fails To Act

    After I restored my SE401 as I previously described, it worked.


    Then, I put a short across the output terminals on Ch B with no input signal. I found out that when the "protection circuit breakers" engage they light up on the front panel.


    In my case, two of the four Ch B 2N2147 TO-3 Germaninum output transistors went dead short collector to emitter.

    In an effort to replace them, I had occasion to attempt to measure the Ch B transformer. Both Ch B transformer secondaries DC Resistance are 2.5 Ohm each. The primary is 17 Ohm.


    It sort of proves 'an old saying' some folks have now told me: "Transistors are the protection circuit for the fuses."

    I completely disconnected Ch B and we tested and listened to Ch A. It actually sounds pretty 'sweet'.

    This afternoon, I disassembled the SE401 again and removed the Ch A transformer. It seems to measure the same as the Ch B transformer.

    A friend in the transformer business is trying to develop replicas based upon reverse engineering and measuring my good Ch A transformer.

    I will post about the results.

Thread Information

Users Browsing this Thread

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

Similar Threads

  1. JBL SE401 Energizer, experience anyone?
    By roads31 in forum Lansing Product Technical Help
    Replies: 4
    Last Post: 06-20-2019, 02:14 PM
  2. JBL/UREI 6230 transformer hum problem
    By jamesdstark in forum Professional Amps
    Replies: 18
    Last Post: 12-15-2010, 12:05 PM
  3. L88 and energizer
    By Donald in forum Lansing Product Technical Help
    Replies: 7
    Last Post: 03-09-2010, 07:34 AM
  4. Transformer for Dual 701
    By jcrobso in forum Miscellaneous Gear
    Replies: 4
    Last Post: 02-12-2009, 02:04 PM

Posting Permissions

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