#### UnnamedUser159

Joined May 3, 2016
501
Its 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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#### Dodgydave

Joined Jun 22, 2012
9,850
What was the reason you replaced them?

#### 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 its 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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#### MrChips

Joined Oct 2, 2009
22,505
Why do you go replacing parts not knowing if they are good or bad?

#### UnnamedUser159

Joined May 3, 2016
501
why dont you tell me something usefull ? I have new parts and replace tda7378 with new one. is it so bad ?

#### MrChips

Joined Oct 2, 2009
22,505
It would be ok if it fixed the problem. Did you get it working?

#### UnnamedUser159

Joined May 3, 2016
501
Did you get it working?
no. it was just a test. like from manual for repairing LCD monitors - replacing inverter ic with new one.

#### Delta prime

Joined Nov 15, 2019
610
why dont 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.

#### Dodgydave

Joined Jun 22, 2012
9,850
So is the Amplifier working or does it still have a fault?

#### Audioguru again

Joined Oct 21, 2019
2,376
The amplifier is 16 years old and its TDA7378 IC is obsolete and not made anymore.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.

#### 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 its in the store from a lot of years

I notice that the heatsink is missing.

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

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