That code indicates a hard disk temperature sensor failure in hard drive bay 1. This Ambient Board is Apple # 922-8524, mfr # 820-2203-A (which I can also see embossed on the part). I purchased a replacement on eBay, but the seller sent me Apple part # 922-7732, mfr # 820-1974-A, which is for the 2006/2007 Mac Pro. The seller tells me it's the same part, but I don't want to put in an incompatible part. Does anyone know if these Ambient Boards (2006/2007 and 2008) are interchangeable?

⟐ Commented May 22, 2023 at 10:42 MST

⟐ Commented April 29, 2023 at 9:40 MST

Nevertheless, it didn't start. No main fans moving. The Graphics card fan moved.After about 0.5-1.5 seconds it turned off. I tried several times always the same.

I had only one problem with it during a cleanup once in the past, where it didn't start.I think it was a loose graphics card at the time, so I opened and cleaned him.Wasn't that dirty to be honest.

Still not working, a few searches and the usual suspect is the Power Supply Unit (PSU). I removed it and a visual inspection suggests it's fine. Capacitors and Coils look fine. Cleaned it, put it back together still nothing.

While reading about trouble shooting, I noticed a red blinking light. CPU A OT and CPU B OT.I tried the button next to it and the SYS_RES button as well. At some point I did hear the startup sound, so I plugged the monitor back in and still the same behaviour as above.

However, after several trials I figured out I can press the power on button several times and hold it. After 3-4 times, the two LEDs CPU A OT and CPU B OT will light up permanently. Once that happens the next time the MacPro starts fully functional, but with the fans on full blast. I didn't find this behaviour documented in the manual, but might have missed it.

Mac Pro Service Manual

I downloaded the hardware diagnostic tool (Link) and put it into

/System/Library/CoreServices/.diagnostics and ran it.

No warnings. The extended test ended as well with "No trouble found" It took 1.5h, so I think the PSU is fine. I'm now running the test again with full RAM installed, out of desperation.

I don't know how to proceed now.I suspect it's some kind of error in the thermal sensors. They're plugged in correctly as far as I can tell. I didn't remove the CPU coolers as I don't have thermal paste. Is there a way to confirm one of the sensors are at fault. Also note they only are lid up after the "Hack", so maybe this is just a special mode?

⟐ Edited by author October 20, 2022 at 17:14 MST

I have some issue with my Mac Pro RAM's. In Macs Fan Control (see attached pictures). And this is in IDLE ! What I should check ? I don't think that this temperatures are OK - FBDIMM Riser A Slot 1 and 2.

Thank you for your ideas :)

⟐ Edited June 07, 2022 at 3:01 MST

Last year I bought two retired mac pro 3,1 from a studio, I am using one of them for everyday PS , AI and some web browsing nothing heavy. Another one have only one 4core CPU, and a broken case, so I leave it unplug and keep it save for spare. Every week , I would plug and boot up the spare mac pro, make sure it is still working. From here, let say the using mac pro is mac pro A(2 x 4 core CUP + AMD 5770 GPU + 32GB ram) and the spare one is mac pro B(1 x 4core CUP + Nvidia 8800 GT GPU + 4GB ram)

Few days ago, I bought a AOC 2236vw monitor from a second head market, which should replace the cinema display(with broken screen). So when I back home , I replaced the cinema display with the AOC monitor on the Mac Pro A. Later that night, I found that the Mac Pro A have serious fans noise and no response(black screen). I force the Mac Pro A to turn off by holding the power button. After that, I try to turn it on again but this time only have white light on the front panel, the fans do spin(no sound, not hight speed) ,also no boot chime. So I try to manual reboot again, this time I heard two "tick" sound from the power supply, the first "tick" happen when I push the power button(white light on), the other "tick" a few second later and the white light off. After a few manual reboot, the Mac Pro A keep stay like that.

At first I suspect the power supply go bad. So I replace the power supply for B to A,(before the replacement I boot up Mac Pro B to make sure the power supply of Mac Pro B is working) however nothing change. So I put the power supply of A to Mac Pro B, it works, and can boot into system. So it seem not the power supply problem. After that, I put the GPU、Ram to Mac Pro B(one by one) all for them are able to boot into system . So what left is the mother board, it must the mother board had fail, I think. So I replace the the mother board , however it keep being white light, again the fans do spin(no sound, not hight speed) ,also no boot chime . And when I put the motherboard form A to B, it boot... which does not make sense at alllllll. (all of the above test have no monitor attached)

At this point I also try to boot with the CPU one by one , no luck with that.

At this point, Mac Pro A have the power supply of B and mother board of B. So I also exchange the little board of them, which the power button is link to, and I also exchange to power button. Things stay the same, no boot of Mac Pro A , boot on Mac Pro B.

The next day morning I try to boot Mac Pro A again. This time nothing happen. No white light no sound no fans spin. It seem there is no electricity getting in to the mac. So, I again exchange the power supply of A and B(so, this time A and B are having their original power supply.) Guess what, this time B have no boot, the power supply is dead.( No white light, no sound, no fans spin, no nothing)

Well well, however Mac Pro A did boot into system, but just one time, after reboot it go back to the white light situation, no more success boot that day.

And the next next day, mac pro A did get boot into system sometimes, but it would fail if I try to reboot it. And a few hours late it might be able to boot or it might not. The power supply of B stay dead.

If I have a successful boot, the optical drive will make a noise .When boot into system, the mac pro A work normally, I put it in to the cinebench r23 test, it will finish the task. Sometimes if I leave it power on long enough, it will shut down by itself and not boot again.

I have no clue if the aoc monitor have anything to do with the fail. I do not think linking the mini display port could cause any of this, it should be just coincidence.

I do a lot of google search about mac pro 3,1 white light problem, no luck, I am running out of idea. Here is my last hope.

It seem that the mac pro 3,1 long white light problem have no systemic answer so far. I hope I provide enough detail for the community the know more about this. Hope we can fix this in the future.

this is the Logic Board Diagnostic LEDs when the long white light happen on my case. Some other people on the internet seems to have the same result of this.

Thank you for your attention, wish you good luck, keep healthy and keep happy.

⟐ Commented May 17, 2022 at 22:40 MST

I tried using cedar cables but it will not boot when pressing the C key or option key

⟐ Commented March 31, 2022 at 10:20 MST

I have a MacPro 3.0 early 2008 with 8 GB of ram and Dual 3.0 Ghz Xeon, Original GPU (don’t know the model, Nvidia without a fan).
It was running very well under linux (Xubuntu) 24/7, mainly for foldingathome project, so heavy load (it’s like mining on CPU but for science).
During the week-end it stopped working, and when i tried to access it, the fans were spinning at 100% speed but completely cold, screen was black, mouse and keyboard were not working, power led was steady on. So, I long pressed the power button and tried to reboot, power led come up steady, fans spin (low speed), HDD spin, 4 red leds flash once on each ram riser. Nothing more, no chime and screen black, the computer keep running like this forever.

So here is what I have tried so far :

• DIAG button: LED “ Trickle'“ Yellow, LED “PWR-ON” Green.
  So PSU is good.
• All Ram combination possible, one in each, two in each, three in each, …
  No changes at all, even without the rams the computer act the same, especially the power led don’t blink and all riser leds flash once at startup.
• RTC reset, Removing the cell 20 sec, put back in.
  Computer restart itself when power cord is plugged back.
• SMC-Rst button.
  Shutdown the computer if ON and no restart. if pressed when Computer OFF, CPUA and CPUB OverTemp flash red once. Shouldn’t block the booting process. But could be the core of my problem
• GPU on all PCIe is unresponsive. Tried an other GPU (Nvidia quadro FX1700), fan spin at full speed but nothing on the output. Tried without the GPU and same behaviour than with it. I will try the GPU in an other computer.
• Disconnect ambiant board : Fans spins at full speed
• Disconnect heatsink temp sensor: Fans spins at full speed
• Power on the USB ports (mouse light up during two second then off).
• Didn’t touch the CPUs for the moment.

I’m not a newbie in laptop diagnostics (even at motherboard and microsoldering level), but never tried a desktop one and especially an apple device. So if you have any advice on things I can try, just tell me. Also if someone have a link for the motherboard schematics, diagrams or repair manual it would be super usefull.
Thanks in advance for your time.

When I switched my Mac on this morning, it worked for a short while, then the screen displayed some small squiggly black lines all of a sudden. I could move the cursor for a few seconds after this, then everything crashed. I held the power button to power off and tried to switch back on. When I did, the same lines were on the screen and wouldn't boot properly. In a panic, I searched Google and tried a few forum suggestions. One solution was to hold cmd+ctrl+opt+A+V keys. I did this despite not having a clue what it was doing, there were just lots of other people who this worked for so I thought it'd be worth a shot. It didn't work and put my mac in a boot loop. It tries to load on the Apple logo and then I get a message: "Your computer restarted because of a problem. Press a key or wait...."

I suspect its the graphics card, so I opened my machine and took the graphic card out, cleaned some dust and placed it in a different PCIe slot. The same problem persisted. I removed the VGI screen connection from the port and powered on again. It didn't seem to restart this time although its difficult to tell without the screen.

After a little more research, someone I saw on YouTube suggested using the reset button on the logic board. I did this. Still nothing. I then used the button just behind the RAM to check the diagnostic LED indicators. This is the result:

When power is off:

SLP: Off

STBY: On - Yellow

ERRB: Off

ERRA: Off

OT B: Off

OT A: Off

GPU: Off

PWRG: Off

EFI: Off

When I switch on:

SLP: Off

STBY: On - Yellow

ERRB: Off

ERRA: Off

OT B: Off

OT A: Off

GPU: Off

PWRG: On - Green

EFI: Off

Anyone know what this means and could help me diagnose?

Please keep in mind that I had to temporarily remove the RAM to be able to actually get to the button and see the LED's. (I don't know if that has anything to do with the indicators or if it will affect the diagnostic result).

A couple more things you might need to know in order to help me here... About a week ago one of my RAM modules failed and I had to remove it and reconfigure my RAM setup.

Also, I saw someone on another forum suggest it might have something to do with the freezing weather - apparently this can cause the PSU to fail or something?

(3.1, early 2008 - all original specs except additional HD)

I'm a bit of a noob so apologies if this doesn't make sense. Hopefully its detailed enough!

Thanks in advance and merry Xmas :-) (y)

I got my Mac Pro 1,1 for basically free (one of the schools wanted to throw this equipment away, so I said I would take it away and try to fix it). The problem is that this MP won’t boot — after powering it on the front panel light got solid and nothing happen. So I check the diagnostic LEDs to see what’s up and they showed me that the CPU A and CPU B is overheat (even if the computer wasn’t turned on). I checked the CPUs, changed the thermal paste and try again - but still same results. In the meantime, I also tried reconnecting some of the cables from MOBO, tried changing RAM, HDD… but with the same effect.

I want to mention that after I removed CMOS battery MP turned on but the fans were at the full speed and there’s wasn’t any chime or video on monitor.

Any ideas that could help me with this problem? Or is it completely dead and I should electro-waste it?

I never had such a computer in my collection so I would like to revive it if there’s a chance.

yesterday there was no electricity at home for about 30 minutes while I was at the PC, once the electricity is back, the mac no longer starts. These are the diag leds on the motherboard.

EFI LED Off

PWR LED ON

GPU PRESENT LED ON

Trickle Orange LED ON

la mia configurazione é :

Mac Pro 2,1

8 Cores Xeon X5365

16GB Ram DDR2 FB-DIMM 667mhz

256GB SSD Samsung 850 EVO

Radeon HD5770 1GB Mac Edition

Mac OS El Capitan 10.11.6

⟐ Edited by author November 20, 2020 at 10:28 MST

TLDR; My Mac Pro 2,1 won’t post for absoloutley no reason (Status light blinks twice a second) and I’ve reset SMC, replaced CMOS, and tested good sticks of ram. I recommenced you read!

here the behaviour I recorded https://www.youtube.com/watch?v=Q9Za26LX...

I have tried the “MacPro2006-2007FirmwareTool.zip “ which errors out with a code of 5530

Apple “Mac Pro EFI Firmware Update 1.2” which says it doesn’t need the update

So I need a little help

My existing setup:

MacPro 2006 1,1, dual 3.0MHz “unknown processor”, 8 Cores, OSX 10.7, 16GB Ram

⟐ Commented February 27, 2020 at 19:31 MST

I put another drive into the HDD BAY 2 and the system won’t boot, there is no beeps. Once I remove the drive then it boots. I put the new drive into the USB and it works. so I guess the drive is not defective, once I formatted in the USB enclosure and I put it back to HDD Bay 2, and again no boot.

after some troubleshooting I put the SSD into the Drive Bay using some adapter to mount, hoping it’s some power issue on the 5 1/4 drive bay. But it won’t boot up, not until I unplug the BR drive power. It’s like it’s either the BR or another drive they won’t work together in all. I don’t know if it’s some power issue. I used to run a second drive in the HDD drive bay but somehow the drive got corrupted. It took me a while to get a replacement. I don’t even remember if I got the BR and SSD running back then together.

But as of now, I can’t seem to get the BR and all the drive running all at once. If I connected the BR, then I can’t connect another HD in the drive bay, it won’t boot at all.

It’s a lot and it’s an old system with patch to the OS… . Just see if someone has similar experience to share.

I recently trash picked an ATI Radeon 5770 1 GB video card for one of my early 2008 Mac Pros I had sitting idle. I installed it today, and when I tried to turn my Mac Pro on it just kept replaying the startup chime over and over again and produced no video. The card fan was spinning, and I made sure the card was seated in the PCI-e card properly & the booster cable was seated properly too. The unit does not do this with another known good graphics card.

I really want to get this graphics card to work. Where would I even start? Or is it just not worth my time?

Here’s a video of the boot chime loop

⟐ Commented November 07, 2019 at 4:40 MST