mac pro 2008 won't turn on

Before you do major surgery, check the coin cell, half hidden behind the graphics card slot. should be close to 3 Volts in your hand. the holder is delicate, try not to break it.

It seems odd, but the power cord with its large chunk of rubber is also a candidate for problems. Be sure to jam the Mac-end back into the socket very firmly, or consider changing it for a "normal-looking" IEC electronic power cord.

Inside most Mac Pro silver towers, there are some LEDS that can demonstrate whether the "always-on" standby power is working. It may take a button push to light it up.

Did you get this problem solved? I'm a having the same issue with my 2008 mac pro! I pressed the diagnostic button that's behind the memory bay and I'm only getting an orange light on the standby led.

Tdutton--

If you have the 3 Volts in the battery, but do not have the standby power, your Mac cannot start.

The power supply needs to provide standby power to get anything else to turn on.

RURALAREA--

You also need the 3 Volts in the battery, in combination with standby power, to get your Mac to power up.

Thanks for responding, appreciate it greatly! Will buy a new 3v battery tomorrow and see if that works which I'm really hoping it does.

BR2032 is what was installed, but CR2032 are used in car key fobs and garage door openers. Similar, but not quite a slow discharge or as wide a temperature range. Will certainly do in a pinch.

We'll I changed the battery but the result is still the same it won't start! Im wondering if the logic board has gone bad, i remove all the part from the inside and found out that the FireWire cable that runs from the back to supply power to the front ports was crystallized so I'm wondering if that messes the board up

Most power functions act like circuit breakers rather than fuses. If you can eliminate the problem, it should perk up, but another round of resets may be required.