Printable View
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.
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
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.Quote:
Originally Posted by script56
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.
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.