Ayuda soundstream L1.2100D

[Perry Babin]

Looking at the output at the speaker terminal with the scope set to 5v/div and 2ms, do you see a nice clean line (no signal) or a sharp waveform (signal driven into the amp)?

 

[Mjimenez]

I get those two readings it moves and it looks good and another time it gets deformed

 

[Mjimenez]

He mentioned that all the tl072c and the 074chood were already changed except lm6172 since I can't find any lafo

 

[Perry Babin]

Are these at the speaker terminals where you'd connect a speaker?

 

[Mjimenez]

Yes

 

[Perry Babin]

The inductor is likely shorted and the capacitors are likely out of tolerance. There shouldn't be more than a trace of carrier at the speaker terminals. It's generally a weak triangle wave that no more than about a volt.

 

[Mjimenez]

How many Henrys should this coil measure?

 

[Perry Babin]

Various diagrams for this type of amp give a wide range of values. What's it reading?

Bear in mind that MANY shorts in transformers and inductors are intermittent and removing them from the board to check them breaks the short and makes it seem to be OK. It's virtually always better to find the short while it's in the circuit, undisturbed from it's original mounting (solder and fixative).

 

[Mjimenez]

some replacement of lm6172im and i will check the inductor again

 

[Mjimenez]

Hi, I'm back, I hadn't checked it because I have more work, Oky now I have already checked the inductor and it doesn't have any short and the other voltages are fine at the 5 volts irf640n at the source and gate pins but still doing the same It fails when I connect the inductor makes a squeak, is there any other component connected to the output of the inductor that can land or cause a short?

 

[Mjimenez]

I already managed to stop making the inductor noise, but now it sends me 70v at the output ... What should I check?