MP 1,1-5,1 Early 2008 MacPro (3,1) won't boot

[reevescajr]

No opening chime and no video on either of the two monitors, so I first replaced the video card. Didn't help. I have a copy of the service manual, so I started through its troubleshooting steps with no problems, getting to the Logic Board Diagnostic LEDs step. I removed the upper memory riser so I could see them, and the MacPro chimed and started booting when I pushed the power button. I've swapped memory strips between the two riser boards, and it won't boot if the upper board is plugged in, with or w/o memory installed. It will start booting if the lower board is in the upper slot. Plenty of the boards on eBay, so I'm wondering if they are a point of failure. I ordered one of them to see if that will fix things. According to the service manual, it's not supposed to operate with only one riser board installed, and it does not. It gets to a point in the boot cycle and stops, probably with some kind of memory error (still no video when it starts booting that way).

I'm also wondering about the Logic Board Diagnostic LEDs. None of them light up when I turn the computer on nor when it starts booting. According to the service manual, some of them should be lit. Maybe they don't light until a certain point in the boot cycle?

I bought the MacPro new in 2008.

 

[RumoredTone]

Hi there,

I'm sorry you're having trouble. I can't say if the 3,1's riser boards are a common point of failure, but I can say that these boards and RAM modules can be finicky. They tend to be sensitive to dust or other contact issues, and can benefit from an occasional cleaning and reseating. In my own experience, I've seen warning LEDs or ECC errors in the system log, which are fully cleared up by taking out the boards, removing the RAM, lightly air-dusting and reassembling.

As a side note, if you've never replaced the PRAM battery on your 2008 Mac Pro, it likely needs a new battery at this point. My 3,1 came with a CR2032, which I had to replace in recent years. I believe later Mac Pros and some other Mac models came with BR2032, which would also work and may last a bit longer in the heat of the Mac Pro internals. CR2032 would be fine though, and is much easier to find.

Even if you don't replace the battery, it'd be a good idea to reset your PRAM if you haven't already. Hold Command-Option-P-R during startup until you hear the startup chime a second time. It's usually recommended that you do this multiple times in a row if it's for troubleshooting, since successive resets do a "deeper" purging of PRAM data. Given that you're not always getting a startup chime, though, it's possible the PRAM reset might not register. So removing the PRAM battery and unplugging the Mac Pro for a short time would be an alternative, to reset power management.

One last note: If nothing else works, you might try booting with no hard drive connected. On rare occasions, a bad drive can interfere with powering on.

Hope this helps!

 

[Ben J.]

FWIW, my 2008 3,1 MP served me well for a decade, and has been mostly sitting unused in a corner the last few years. When I press the power button like, once every six monts, it sometimes takes a few tries, nothing happens, a few more tries, and eventually it chimes and starts up and runs just fine.

 

[reevescajr]

Thanks to both of you for your replies. I've had both riser boards out and back in several times with and w/o memory installed, and it just won't start booting if the top riser board is in the top slot. I don't recall if I tried it in the bottom slot, but will do so. I'll also clean the contacts of the board. I have changed the PRAM battery, which I don't recall ever doing before. Since it starts booting every time w/o that riser in the top slot, I suspect the power switch is OK.

 

[reevescajr]

I cleaned the contacts of the upper riser board, although they looked fine. The computer does not chime if it is in either the top or bottom slot. It does chime if the other riser board is in either slot. Hopefully the replacement riser board I ordered will be here this week, and that it fixes the problem.

 

[reevescajr]

Replacing the memory riser card did get the old MacPro running again.

 

[RumoredTone]

Thanks for the update. It's great to hear that the new riser worked out.