Hifonics BXE1250.1D without audio

[Mjimenez]

Hello friends, I am looking to solve this problem. It is a hifonics BXE1250.1D amplifier, initially the problem was in the power supply and it was solved, but now in the output I have oscillation and voltages of +-15v in operational amplifiers and still apparently no audio signal arrives which appears to be an irs2010s, but when I touched parts of the pre-amplification I managed to see audio at the output of the amplifier, I already changed some operational amplifiers and I couldn't get it to work beforehand, I appreciate your support and send greetings to the group

 

[Perry Babin]

when I touched parts of the pre-amplification

^^^ Please clarify.

 

[Mjimenez]

when I touch any terminal of the largest potentiometer

 

[Perry Babin]

Have you tried operating all of the pots and switches through their entire range with a signal source connected and a speaker connected to the dead channel to see if the channel ever produced any sort of sound (even if it was just static/noise)?

Does your signal source have a grounded shield?

 

[Mjimenez]

Good evening, yes, I tried it and I did not observe any sound in the speaker and movement in the oscilloscope.

 

[Perry Babin]

Does your signal source have a grounded shield?

 

[Mjimenez]

The signal comes from a car stereo that I chose to use to inject audio into the amplifiers

 

[Perry Babin]

Both of these without the RCAs being plugged into the amp.

Resistance from the head unit's shield ground to the case of the head unit?

Resistance from the head unit's shield ground to the main ground terminal on the amp?

 

[Mjimenez]

in the main unit 950 ohms and in the amplifier more than 18.8 Mohms

 

[Perry Babin]

What are you using for a signal source?

Is it being powered by the same 12v supply as the amp?

 

[Mjimenez]

I am injecting a 45 Hz signal through a stereo and auxiliary and they are being fed by the same power source

 

[Perry Babin]

Stereo? Standard head unit?

Auxiliary?

^^ sounds like you're using a home stereo (which I did for years).

 

[Mjimenez]

It is a car radio, here where I live we call them car stereo and it has an auxiliary input where I connect my cell phone and inject the 45 Hz signal for a bass amplifier or 1000 Hz for a full range amplifier.

 

[Perry Babin]

Trying not to make any assumptions.

For a standard head unit, the output RCAs should read 0 ohms to its case. If it doesn't, that needs to be resolved. This is one solution, or you could go into the head unit and repair it.

If the head unit is being powered by the same power supply as the amplifier, the case of the head unit should read 0 ohms to the ground terminal of the 12v power supply.

 

[Mjimenez]

I will try to repair the car stereo and see if I can now generate audio in the amplifier. Thank you for your support. Tomorrow I will update the information about it.

 

[Mjimenez]

Well, I have tried to repair the main unit and it seems to work fine, what I found wrong was an open 1k resistor of the amplifier that is located between the secondary ground and the main power ground and it gave me sound, although very low. Previously I repaired one of these amplifiers and it worked in the same way, I lost a lot of time trying to solve and in the end with a good car radio, it worked well (my car radio is not good), I hope that is the case, greetings and thank you very much Mr. Perry Babin .