Inter-m L2400 amplifier

Thread Starter


Joined Mar 2, 2014
Hi guys. im new on here so take it easy with me lol!. i repair amplifiers and electronics for a living and iv been given an amplifier by a customer for repair.. but this repair is doing my head in! its a 2 channel inter-m l2400 amp when the amp powers on it runs fine! Channel 2 works perfect but channel 1 has no sound, there are no protection lights on to say there is something wrong it just doesn't play sound through the first channel. i have measured and checked everything in the amp and found a diode that had gone so i replaced it hoping it would fix the issue on the first channel but no joy!. when i have the amplifier switched to parallel i can hear the sound ever so quietly through number one but when i turn channel 2 up it almost sounds like its leaking across to the other channel but only very quietly! i have check the volts on both sides and they are reading the same so i know its getting enough power.... can anyone give me any suggestions about it? its driving me mad and want to get it off the bench!



Joined Oct 2, 2009
I am a bit surprised that you are coming to us for help when it should be the other way around.
I assume that you have a standard collection of test equipment, oscilloscope, signal generator, DMM.

Do you have access to the service manual and the circuit schematic?
Can you point us to a link to the circuit schematic?
With a circuit diagram we will be better equipped to provide you with some test procedures.


Joined Nov 30, 2010
do u use an inter-m l2400 aswell?? dont think thats the problem but i will deffo look into it :)
No. That's why I quoted your statement about a parallel setting. That might mean the same thing as a, "mono" switch, and it might not. Just use what helps and ignore the rest. A lot of people might offer advice that is irrelevant until we get a schematic here.