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Reverse polarity damage

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Hi, I have a circuit like below figure to provide 5V from a 3 volt battery.Once I connected the battery in reverse direction and it failed.But when I replace all parts with new ones the circuit still didn't work! The problem is that two leads of C2 are short circuit, even when there is not any capacitor in that place! What can be the problem!? Is pcb damaged?!

MAX1674_converter.gif
 

Is your C6 rated for 3V? Was it exposed to 5V output?

Several components allow a path which might short the leads of C2. You'll need to test them individually, out of circuit.
 

To the original poster: if you have replaced all components, and by that I mean ABSOLUTELY ALL THE COMPONENTS, then something else downstream on the load also was damaged.

The way I read the schematic, Brad, is that it is a 47.0 uF capacitor rated at 6.3 volt. Remember that in some countries they use a comma instead of a decimal point.

But it is confusing.....no spaces between values! Also, labeling a 47 uF cap as 47.0 uf, which most likely has a +/- 20% tolerance is completely irrelevant and adds to the confusion.
 
Hi,

Also, labeling a 47 uF cap as 47.0 uf, which most likely has a +/- 20% tolerance is completely irrelevant and adds to the confusion.
Click to expand...
Very true from the physical/mathematical point of view.
In our case we have a company_internal rule to mark all standard resistors and capacitors with three digits (4.70u, 47.0u, 470u. No units, no leading zeroes like 0.47u --> 470n) in the schematic. This was necessary to get a standard "value" format, that is easy to process.
This also eases a function the for "true value" sorting. No alpha sorting, no numerical sorting...
And it avoids the confusion (especially for non-electronics personal) when one person talks about 0.47uF and the other about 470nF.
When we print out a purchase list, then those values are like the distributor names it.

Klaus
 

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