Mac Pro 1,1 only starting second time after it has been turned off for a while

[647156]

I have a Mac Pro 1,1 (dual 2.66, 4x1 GB memory, GeForce 7300GT) which works fine except that when it has been turned off for any length of time e.g. overnight or even just an hour or so it seems, although left plugged in, when next started on the first attempt the power light and fans come on as normal but I don't get the boot chime or a signal to the display, and the red light next to CPU B Error on the logic board comes on a couple of seconds after pressing the power button.

If I hold down the power button to turn it off and then immediately start it again, it always comes on perfectly the second time, it never takes more than two attempts to start. It doesn't need to have been on in its non-booting state for any length of time so it's not an issue with components needing to warm up first.

Once running, if I shut it down and then start it again relatively soon afterwards (eg 10 minutes later), it starts up fine the first time, the problem is only after longer periods unused.

This is absolutely baffling me as I have done extensive searching but can't find anyone with the exact same symptoms, and I have only had the machine for a few weeks and it was working perfectly to begin with, this has only started more recently but it is consistent i.e. it only starts second time if it has been off for a reasonable period of time.

I have already tried the following:

-- Replacing the logic board battery with a new one

-- PRAM reset (Cmd+Opt+P+R at startup and hold until two boot chimes have sounded)

-- Starting without the SSD being connected, this being the only non-standard component installed


SMC resets – there seem to be a lot of possible ways to do this on various sites, so I have tried all of these:

-- Unplugging for 15 seconds, plugging back in and waiting 5 seconds before starting up

-- Unplugging, pressing the button on the logic board just below drive bay 4 for 15 seconds

-- Pressing and releasing immediately the button marked "SMC_RST" behind the memory cards, with the machine still plugged in

-- Unplugging and holding the front power button for 45 seconds


If anyone has had an issue like this before or can provide any pointers it would be much appreciated!

 

[El Awesome]

I could imagine that your PSU seems to be dying. Your CPU doesen't get enough power, and as soon as some power is build up, it works.

Do you have another fitting PSU to test if it works? I don't think that buying such an expensive PSU without really knowing if it really is the PSU.

Do you have something to check the voltges? Dying PSUs often give wrong volages, this is why the CPU LED might have turned on.

 

[647156]

Many thanks for the reply - I don't have another Mac Pro or any parts for it I'm afraid, but if it's the only way to sort this out then I don't mind buying another Pro (perhaps a parts one) and swapping the power supply if that's the likely cause?

I don't have anything to test the voltage with either - is there any other way to check for an iffy power supply?

 

[combo]

I'll second what El Awesome said and bet that your PSU is failing. Second bet would be on the CPU.

I just went through the process of confirming and then replacing a failing PSU. My symptoms were slightly different from yours, however (see below). I never saw my CPU diagnostic light switch on and I never heard my fans spin up when my machine was failing, but then I have a different model than you.

Here is what happened to me, the advice I gathered, and my eventual solution.

Symptoms and specifications:

• Mac Pro 3,1 (Early 2008) - 8 x 2.8Ghz
• Pushing power button on front would result in audible click, followed by a softer click 5 seconds later as the machine cut power to itself.
• Normally, there would be an audible click followed by a half-second delay, followed by the fan on my video card spinning up. Then hard drives would spin up
• Failed power ups would happen only 10% of the time at first. Things went progressively down hill over the course of a few months until finally the machine would not start up at all
• In the initial phases of failure, I could power up the machine after it pooped itself the first time. However, this entailed unplugging power cord and letting the machine sit for a number of hours. As mentioned in the above bullet point, this would eventually stop working

Tests and procedures:

• Prior to everything, I pulled off the side panel and cleaned the crap out of everything. Whipped out some canned air and blasted my graphics card, fans, hard drives and RAM risers. No success.
• Did SMC resets as you noted. No success.
• Swapped PRAM battery as you noted. No success.

I dug around online and spoke to a Genius at an Apple Store. The Genius suggested sequentially removing components to eliminate the chance that one of them was causing the problem. He noted that my graphics card (2600xt) was kind of known for choking power ups.

• I first removed all hard drives (I have all 4 of my bays filled) except for the boot drive. This actually let me boot up! However, after powering off, I could not restart the machine again. Indicative of failing PSU.
• I then removed the graphics card, leaving only the boot drive in. I monitored the power up status with the diagnostic LEDs. No success.
• I then removed the boot drive, leaving the machine pretty much bare. I monitored the power up status with the diagnostic LEDs. No success again.

Results and fix:

• I eventually caved and decided to get a PSU replacement. I bought mine from gainsaver.com, the only place I could find that actually carried the part aside from taking it into an Apple store. And, it was significantly cheaper than an Apple component because it was pulled from another unit. I recommend gainsaver if you want to check for components.
• I swapped out the PSU using the following video guide:
• ------youtube
• -------This was for a newer model than mine and there was a difference when I took apart my machine. There is an a panel behind the optical drive that is secured with two phillips head screws. Behind this panel, my cables were velcro'd to the case. In the video, they state that you can first remove the PSU and then unhook the cables. Not so with my PSU. I had to remove the panel mentioned above, unvelcro, and then unclip before I could feed the cables past the PSU fan and fully remove the PSU.

edit: forgot to mention that after switching PSU, machine booted right up. Have not had any problems since (knock on wood).

That covers most everything. I think a CPU swap might not be too bad either if that's what your testing suggests is actually failing. Again, note that there were differences between how my machine failed and how yours is failing. But, on these older machines, I think a failing PSU is a highly likely culprit.

 

[El Awesome]

Many thanks for the reply - I don't have another Mac Pro or any parts for it I'm afraid, but if it's the only way to sort this out then I don't mind buying another Pro (perhaps a parts one) and swapping the power supply if that's the likely cause?

I don't have anything to test the voltage with either - is there any other way to check for an iffy power supply?

iStat Pro tells you the voltages. They aren't 100% correct, but definately enough to check if everything's fine.
You have a 30 free trial, you max want to download it.

I have around 1V (0.95V-1.05V) for my CPU, 4.94V for my ODD, and 12V for HDDs and PCIe stuff. That looks okay to me.
But the interesting thing would be to find out the voltages after a cold boot - a simple voltage measuring tool is enough. Almost everybody has one, maybe you can ask a neighbour or so. They look like the pic attached.

This thread can be helpful: https://forums.macrumors.com/threads/1082046/

Good luck!

 

[647156]

Thanks again - guess I need to try and get another PSU/another machine then I do already have iStat Pro but couldn't see any mention of voltages or it being a trial version, is this the Dashboard widget that you meant or something different?

 

[El Awesome]

There is also one called iStat Menu (sorry my mistake), which shows you some stuff on the bar on top of the screen.

 

[647156]

Update on this - I've now picked up another Mac Pro 1,1 and it seems that it wasn't the PSU or indeed anything that I have tried, so I'm guessing there must be something odd with its logic board

I swapped in the PSU from the other Mac Pro and still had this issue starting up first time after an hour or more of being turned off, yet that PSU in the other, identical, machine doesn't seem to have the issue (so far at least - starting to think maybe all used Mac Pros are unreliable!).

Also tried removing the graphics card and booting without it, and using some different memory and riser cards, and still the same - CPU B error when starting, then it comes on fine the second try...

 

[Loa]

Hello,

I'm going for a long shot here: isn't there a small battery inside the Mac that should last for a long long time but sometimes fails? Your situation looks like that battery going dead, and the first (failed) boot is just enough to charge some condensator, allowing you to boot normally the second time.

Loa

 

[combo]

I'm going for a long shot here: isn't there a small battery inside the Mac that should last for a long long time but sometimes fails?

He already tried switching out the PRAM battery.

If you suspect the logic board, you can try to see if you have any bulging capacitors. That's usually a sign that the logic board is failing. Here's a link to a pretty good image of bulging capacitors. A google search for them will turn up heaps more.

If you managed to get your hands on a whole new MP1,1, you could try swapping CPU B between the machines, but that honestly might be more work than it's worth.

 

[647156]

Yeh, the battery was the first thing I thought of as my old Power Mac 6100/60 also needs a double start when it hasn't got a battery installed, but it didn't seem to be that.

I can't see any bulging capacitors, although there could be more capacitors that I can't see underneath the front fans or processor cover.

Yep, doesn't seem worth trying to change the processor, it's difficult to get to the CPUs and I don't want to have to mess around with thermal paste etc and probably just make things worse - CPUs don't tend to fail so I'd be surprised if it was that.

Don't suppose there's anything in the reference to the boot ROM that the service manual has under the CPU error light section, is there - if the boot ROM was corrupted the issue would presumably happen every time?