TDA2005 build took a rout to fail.

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#24
^ Ground remains the same at pin 6, but it puts V+ on pin 3. Pin 3 appears to connect to V+ internally thru a resistor anyway, so maybe there's hope. I was also going to suggest double-checking the polarity of the electrolytics. I think it's fixable.
 
#25
! said:
You have shown us a schematic but what is the power supply to it, exactly (in circuitry details if possible)?

The schematic for your project is incomplete. What I mean is, it shows only an amp subcircuit which assumes (near enough) perfectly clean power up to that point in the circuit. It only has a power rail decoupling capacitor of 0.1uF (= 100nF). On the same PCB as the amp chip you should have far more than 0.1uF. The datasheet for TDA2005 suggests 100uF for "Figure 23 : Bridge Amplifier without Boostrap" (they need to proofread more!) which seems reasonable if your power supply itself has at least 1000uF capacitance in it (even more is better).

Your C4 polarity is reversed! Your PDF shows the wrong capacitor orientation on the component outline picture, look at the etching picture and the schematic, negative polarity should connect to ground and positive to pin #3 of the amp chip.

Also, you will get better performance if you increase the capacitance of C4 higher than 10uF (100uF or a little more) and also if you were using a lower ESR capacitor. If you want to stick with 10uF, try using a tantalum capacitor for C4 but MAKE SURE the polarity is right as they can pop quickly if polarity is reversed. Would a reversed C4 cause your specific problem? I do not know, but doubt that it would work properly with it reversed so I suggest correcting that polarity problem as the first step then retesting.

In this picture, http://i55.tinypic.com/nclhtt.jpg of the back of the amp chip, I see a couple little whiskers or hairs or something around the chip pins. If they are metal they could potentially short chip pins. Take a toothbrush and clean those out of the chip pin area. Otherwise (from what I can see of it in the picture), the pins look ok, I do not see a problem resulting from bending them. The picture of the bottom of the PCB also shows some kind of whisker-like fragment on the lower left side between one of the traces from a chip pin and the wide left-most trace (probably ground) which should be cleared off.

Otherwise, is this lead containing or lead free solder you used? Good leaded solder joints usually look shinier. It might just be an optical illusion from the picture but the solder joints on the lower row of chip pins look a bit granular and questionable. Ideally you would apply flux only to these joints and reheat them (no more solder is needed, just to rewet and flow the solder that is there)... but as mentioned above I would reverse polarity on the capacitor and retest before doing anything else.

As for your multimeter, maybe it just needs a fuse replaced?
Click to expand...

Which one is the decoupling capacitor. is it C3?
 
#26
^ Yes, C3 on your PDF. There should be a (roughly) 0.1uF capacitor there but also 100uF or more in parallel with that capacitor, with more being better up to some practical limit like around 2000uF.
 
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#27
sofaspud said:
These cannot both be true, so it's up to the OP to determine.
Click to expand...

And they are not. The printout of the copper side is flipped. You see it from the bottom, not as usual as see-through from the top. What you saw is pin 11 to C5 and from there to pin 10. Pin 1 goes to C1 and pin2 to C6.

4pyros said:
The chip may be blown now!
Click to expand...

Looking at the solder joint and cosidering the soldering time and temperature it must have taken to produce them without flux, that could indeed be true.
 
#29
Yes the amp chip really is in *backwards*. Now the question is, does having it in backwards make it likely it was damaged. 12V power rail was supposed to go to pin 9, but is going to pin 3 instead, the supply voltage ripple rejection pin. The chip may survive this.
 
#33
Hey everybody, I have an update.
Flipped the chip and soldered the 2200 uF capacitor, amp works, but the sound is very distorted. After poking around i found out that my battery is dead. I am currently charging it. I will post the results when the battery is done charging.
 
#34
Hey everybody, I have an update.
Flipped the chip and soldered the 2200 uF capacitor, amp works, but the sound is very distorted. After poking around i found out that my battery is dead. I am currently charging it. I will post the results when the battery is done charging.
Click to expand...
Once again the board was made wrong and the chip was backwards.

cepa; If charging the batt dose not help the chip may have been damaged. It is suspect now that you have confirmed the board was wrong and the chip was powered up backwards. Good luck.
Andy
 
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