What's up friends? Before everyone merry Christmas to all ... this time I ask for help to repair this hifonics z-1000D amplifier in which I have an oscillation problem in the power source and the problem enters through pin 16 of tl494, I would like to know if I They can help to solve the problem, I already checked the output fets and they are fine, if I remove them it works fine and when I remove the 74 kohms resistor that goes to 16 pin of the tl494 it works but the power supply transformer heats up, I don't know if there is any diagram to help me repair it in advance greetings and a big hug
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Does the amp produce audio with the outputs and resistor in the circuit?
The frequency seems to be high for those components. It should be about 37k. One could be out of tolerance.
That said, the photos I have of similar amps use a 18k or a 22k for timing which would make them operate at even lower frequencies.
The frequency seems to be high for those components. It should be about 37k. One could be out of tolerance.
That said, the photos I have of similar amps use a 18k or a 22k for timing which would make them operate at even lower frequencies.
very well, I'll try changing the resistance and see how it reacts and yes i have sound
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I have already tried several resistors from 18k to 20k, it lowers the frequency, but the problem continues, I have disconnected the rectifier diodes and it works well, but when I put them back in their place the fault appears again, I have not been able to find which components are trying to turn off the tl494, it even does it without the output fets.
Does the transformer heat as quickly at the lower frequencies?
Are the PS FETs heating up?
How hot does the transformer get?
How long does it take to get to where you can't hold your hand on it?
Are the PS FETs heating up?
How hot does the transformer get?
How long does it take to get to where you can't hold your hand on it?
the transformer does not heat up too much, it only increases temperature but it is bearable and that only happens if I remove the 15kohms resistance it does not heat up being inside
yes, in the first instance I tried to leave it without that resistance and I tested it in the car and it blew the fet of power source
Do all FETs in both PS banks have precisely the same drive signal?
What do the drain signals look like?
Are the PS FETs heating up?
What do the drain signals look like?
Are the PS FETs heating up?
I changed the switching transistors and all the fets, the photos I uploaded are from gate and if they are the same, in drain the wave looks deformed and flickers
Something is lost in the translation. Yes or no:
Do all FETs in both PS banks have precisely the same drive signal?
Photos of drain waveforms when the transformer is heating?
Do all FETs in both PS banks have precisely the same drive signal?
Photos of drain waveforms when the transformer is heating?
The signal looks like this because 2.4v reaches pin 16 of the tl494 and tries to turn it off, tracking where it comes from and it is from the 74k resistor, this is connected to another 10k resistor in series and this reaches the + 63v that They come out of this coil and when I remove the 74k resistor the tl494 works fine only the power source toroidal is heated
