MP 1,1-5,1 5,1 Corrupt NVRAM/BootROM would cause failure to detect processor tray SMC?

[davetheghost]

As title states, I've a weird issue.

Friend brought me a 5,1 dual processor machine that has the typical jet engine sounding fans, no data displayed for CPU temps, chipset temp, or BOOSTA or B RPMs. I go into About this Mac, and then System Report, it tells me the serial of the processor tray, but not the SMC version. It properly displays the serial and SMC version of the mainboard, however.

So, on a whim, I ordered a used mainboard and processor try on fleabay.

I initially thought it was the processor tray, but ordered a board just to be sure. I tried the processor tray first, same issue, and doesn't report SMC version. I swapped back planes, and despite fans being full blast, I got the boot chime, which hasn't done so since I first got the machine. It booted a bit quicker, and I went into System Report, and there it is, SMC version of the (newly ordered) proc tray.

So I thought, let me try the old proc tray. Shut down, swapped trays, and it properly reported the SMC for that tray as well. Both are f11, and sadly the vendor who sold me the backplane claimed it was 2010~2012 backplane, but the SMC version is f5.

Any options besides returning and buying a proper backplane?

Thanks

 

[Borowski]

Usually both SMC-versions are shown, even if mismatched.

To suspend a corrupted NVRAM: Start without the RTC battery.

 

[tsialex]

Any options besides returning and buying a proper backplane?

No, a mismatched SMC can't be flashed and corrected since the SMC firmware can't be dumped and never leaked from Apple.

You need to replace the backplane or the CPU tray, make a combo, so both match the exact same SMC firmware version.

 

[davetheghost]

No, a mismatched SMC can't be flashed and corrected - you need to replace the backplane or the CPU tray, so both match the exact same SMC firmware version.

Thats what I figured... though I still wonder if the NVRAM holds parameters that point to the processor tray SMC.. like a key to access it or something.

 

[tsialex]

I still wonder if the NVRAM holds parameters that point to the processor tray SMC.. like a key to access it or something.

No, the backplane have a dedicated 24C something small flash memory just for that.

You have a hardware problem, maybe a defective SMC. It's common to see SMC failures with Mac Pros that lived near to the sea. The MacPro4,1 and MacPro5,1 Renesas F2117TE20H H8S/2117V secure microcontroller is a TQFP 144-pins that is extremely easily to be damaged by sea air corrosion.

The SMC is completely isolated from the BootROM, nothing SMC related is stored inside the NVRAM - unless you count sensor calibration parameters, but it's not in the volatile area of the NVRAM and the Mac Pro still works if not present, also not related to the SMC firmware which is stored internally to the H8S.

 

[davetheghost]

I see..

definitely a headscratcher.

well ill return this tray and backplane and order a f11 backplane, hopefully that resolves the issue.

the machine is kept and used in an enclosed metal building, no climate control or insulation.

you think some conformal coating on the edges of the main chips would increase its life? i plan on making a dump of the new backplane nvram with macshraubers tool in case things go bad, again.

thank you, many users owe you a beer, as do I.

 

[tsialex]

I see..

definitely a headscratcher.

People are using the MacPro5,1 a lot longer than Apple intended. The last MacPro5,1 was made back in October 2013, so, it's more probable that the one you are working have at least 11 years.

It's not a surprise that a Mac Pro that is being used in a harsh environment failed over a 11/12/13+ years timespan. Besides that there are always the bathtub curve failures.

well ill return this tray and backplane and order a f11 backplane, hopefully that resolves the issue.

If it's just the backplane that is damaged, it will make it work again.

I'd open the PSU and check the electrolytic caps.

the machine is kept and used in an enclosed metal building, no climate control or insulation.

you think some conformal coating on the edges of the main chips would increase its life? i plan on making a dump of the new backplane nvram with macshraubers tool in case things go bad, again.

thank you, many users owe you a beer, as do I.

Apple uses a lot of conformal coating with MacBooks/iPhone/iPad boards, but I don't remember ever seeing a TQFP with it outside some mil spec PCBs.

I'd say that is easier and cheaper just to get spares, but for sure you can try.

 

[davetheghost]

You mean the classic leaking caps that plagued us some time ago?! Not a problem. Hex cap screws underneath?!

Ive fixed quite a few TVs and monitors by just replacing the caps..

 

[tsialex]

You mean the classic leaking caps that plagued us some time ago?! Not a problem.

MacPro5,1 is around a decade later than the Apple products that suffer from that, the failures are more of wear out/drying electrolytic/bulging ones.

ACBel made PSUs have more failures that Delta.

Hex cap screws underneath?!

You can read detailed instructions in the Apple Technician Guide:

https://forums.macrumors.com/thread...an-guide-service-manual.2188557/post-27516704

Ive fixed quite a few TVs and monitors by just replacing the caps..

It's not a panacea, but works for devices that have the leaking or the counterfeit caps.