Blinking white light!

[martinlangley]

Hi all, this is maddening. I have acquired a 2010 5,1 and I'm trying to get it going. Following the reference manual I strip it down to the bare essentials and add components to try and build a working system. The problem occurs when I add a processor tray populated with a processor and ram. When pressing the on button I get a flashing white light and no chime. This has persisted after changing processors, changing ram, reseating ram, and changing the processor tray. I've just removed the motherboard and frozen it for a couple hours. Nothing seems to make any difference. The amazing thing is that all the diagnostic lights and everything check out as normal! This tells me its not a PSU issue which only leaves me with the logic board. Anybody got any ideas? I'll happily pick up the cost of a replacement logic board if this will resolve it but I'm surprised not to have made better progress without such a drastic remedy.

BTW I've removed the power cord for 20 seconds, reset the switch on the motherboard, replaced the battery, etc etc, all the simple stuff...

Anybody got any ideas as to how I could test/diagnose a fault on the logic board?

Anybody got any other ideas?

ML

 

[tsialex]

Hi all, this is maddening. I have acquired a 2010 5,1 and I'm trying to get it going. Following the reference manual I strip it down to the bare essentials and add components to try and build a working system. The problem occurs when I add a processor tray populated with a processor and ram. When pressing the on button I get a flashing white light and no chime. This has persisted after changing processors, changing ram, reseating ram, and changing the processor tray. I've just removed the motherboard and frozen it for a couple hours. Nothing seems to make any difference. The amazing thing is that all the diagnostic lights and everything check out as normal! This tells me its not a PSU issue which only leaves me with the logic board. Anybody got any ideas? I'll happily pick up the cost of a replacement logic board if this will resolve it but I'm surprised not to have made better progress without such a drastic remedy.

BTW I've removed the power cord for 20 seconds, reset the switch on the motherboard, replaced the battery, etc etc, all the simple stuff...

Anybody got any ideas as to how I could test/diagnose a fault on the logic board?

Anybody got any other ideas?

ML

The blinking white it's the SOS signal, when the backplane can't initialise itself. You could have SPI flash problems or something hardware related.

If you don't have another working Mac Pro 4,1 or 5,1 to test each part, buy a replacement backplane and start from there.

 

[martinlangley]

The blinking white it's the SOS signal, when the backplane can't initialise itself. You could have SPI flash problems or something hardware related.

If you don't have another working Mac Pro 4,1 or 5,1 to test each part, buy a replacement backplane and start from there.

Your help much appreciated, - you seem to be confirming my suspicions. Could you kindly clarify that by "backplane" you mean the main logic board into which all the other components plugin?

Best regards

M

 

[tsialex]

Your help much appreciated, - you seem to be confirming my suspicions. Could you kindly clarify that by "backplane" you mean the main logic board into which all the other components plugin?

Best regards

M

Backplane is the correct name for the MP4,1/5,1 Main Logic Board and the CPU board correct name is CPU tray.

 

[martinlangley]

Hi again. I'm in the throes of following your sound advice and acquiring a 4,1 or 5,1 backplane (or full system) to test and eliminate issues. As you seem well up to speed on these matters could you kindly clarify the position with using 5,1 processor trays and devices on a 4,1 backplane. There seems to be a degree of controversy as to how possible/achievable it is. I'm happy to do a firmware upgrade if that is what it takes.

Best regards

ML

 

[tsialex]

Hi again. I'm in the throes of following your sound advice and acquiring a 4,1 or 5,1 backplane (or full system) to test and eliminate issues. As you seem well up to speed on these matters could you kindly clarify the position with using 5,1 processor trays and devices on a 4,1 backplane. There seems to be a degree of controversy as to how possible/achievable it is. I'm happy to do a firmware upgrade if that is what it takes.

Best regards

ML

There no controversy. If you have a MP4,1 CPU tray you have to buy a MP4,1 backplane. If you have a MP5,1 CPU tray, MP5,1 backplane.

SMC for MP4,1 is 1.39f5, for MP5,1 is 1.39f11. If you mix one with the other, the fans will work full RPM/full time and no software will correct this. You can’t upgrade SMC, you can’t read/dump/do anything - it’s immutable.

You can use a mix-matched SMC to do tests, but you will be near a jet plane, no one accepts the noise.
[doublepost=1555335667][/doublepost]Before you ask, SMC has nothing to do with the MP4,1 to MP5,1 firmware upgrade. A MP4,1 backplane upgraded to MP5,1 firmware still has SMC 1.39f5.

 

[martinlangley]

There no controversy. If you have a MP4,1 CPU tray you have to buy a MP4,1 backplane. If you have a MP5,1 CPU tray, MP5,1 backplane.

SMC for MP4,1 is 1.39f5, for MP5,1 is 1.39f11. If you mix one with the other, the fans will work full RPM/full time and no software will correct this. You can’t upgrade SMC, you can’t read/dump/do anything - it’s immutable.

You can use a mix-matched SMC to do tests, but you will be near a jet plane, no one accepts the noise.
[doublepost=1555335667][/doublepost]Before you ask, SMC has nothing to do with the MP4,1 to MP5,1 firmware upgrade. A MP4,1 backplane upgraded to MP5,1 firmware still has SMC 1.39f5.

Hi, - my good friend. Have made substantial progress but now at the last jump. I need to eliminate the PSU as the source of the problem so I'm clear about what has to be replaced or repaired. Having removed the PSU I have searched online in vain for a pinout diagram to enable me to verify it with a multimeter.

I'm sure a man of your wit, charm and erudition would know where to look, - tell me and I'll stop bothering you!

 

[MIKX]

martinlangley

Check your RAM LEDs on the CPU tray.

Also, do some homework Google "Mac Pro blinking LED at startup"