Please give advice about computer audio amplifier repair

Thread Starter

UnnamedUser159

Joined May 3, 2016
501
It`s i-trigue 3330



I have checked
the big capacitor - it was with decreased size | now renewed
the coloured capacitor 470u25v it was 440uf i think | now have new
the small capacitor near it - it was with good capacitance
the six 945 transistors. 5 good 1 fault /replaced now/
the little resistance under the entry capacitor

Have replaced with new:
tda7378
mc4558cn with 4558d

i am not big value repairer but i am learning from lot of time and maybe every experience is good for me .

Thank you!
 
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Thread Starter

UnnamedUser159

Joined May 3, 2016
501
The tda7378 was replaced just for test if things will go okey. 4558d too.

The system has volume control stuff and it`s LED goes green when rotate it left to right but there is no sound. I have desoldered the bass for now
 
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Delta prime

Joined Nov 15, 2019
337
why don`t you tell me something usefull ?
I'm not trying to beat you up, we are here to help you develop the skills and confidence to declare a part good and move on. If you don't, you'll have continuous doubt about what's working and what isn't; you'll go around in circles or end up replacing perfectly good parts. Shotgun troubleshooting is bad troubleshooting. :)
 

Audioguru again

Joined Oct 21, 2019
1,503
The amplifier is 16 years old and its TDA7378 IC is obsolete and not made anymore. Maybe the replacement TDA7378 is a fake Chinese one. The datasheet shows that is has 4 amplifiers made for a car, not for a computer. I do not see 4 inputs and 4 outputs on the pcb.
I notice that the heatsink is missing.
 

Thread Starter

UnnamedUser159

Joined May 3, 2016
501
Maybe the replacement TDA7378 is a fake Chinese one.
i took it from local store, maybe like you said it is fake one or maybe it`s in the store from a lot of years :)

I notice that the heatsink is missing.

it`s just for good picture, of course i will put it back when working.
 
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