[Roypw]

I have the board pictured below. The 12 volt regulator chip is bad, reads 7 ohms to ground on the output pin. Also gets very hot even with the output pin disconnected.

Problem, there are no markings on the chip.  I am sure the 5 volt chip is the same. Can anyone help me identify this voltage regulator chip so I can get a replacement.

So far the supplier has not been able to help.

Thanks, Roy

[nitromethane]

The chip in question is a buck (step-down) switching regulator in a SOIC8 package, and there are many chips that fit this description. I can't tell you much more just from looking at the picture.

Chip uses an external inductor (big gray thing) on the output side to drop the voltage, along side some capacitors (medium sized brown things) that smooth out the input and output voltage spikes.
Then there are some small resistors (black things) that are probably used to set the output voltage of the regulator and capacitors probably there just because the datasheet specifies them.

You could try to reverse engineer the pinout from the board, which should be a step closer to identifying a suitable replacement part.

An example of a switching regulator that could potentially (but likely can't in this specific board) be used in said application would be something like this:
http://www.farnell.com/datasheets/1837055.pdf

[Roypw]

Thanks, I have done a little reverse engineering myself. Pin 2 is Vin and pin 3 is the output that goes to the first inductor (12volt out).  I found a pinout (AP6502) that matches this pin out but of course can't be sure. I ordered 1 from Amazon due June 13 or so.  I will try it unless I get better info from someone.  Still hoping the board seller can help but it's a slow process dealing with China suppliers.