MP 1,1-5,1 Flashing SIL (system indicator light), no boot, mac3,1

[madmac66]

So I got the dreaded flashing SIL at startup. It has given me this intermittently for a few months (once maybe twice a week). I largely ignored it as a) I would long-press shutdown and then reboot and all would be fine b) this is an antique 3,1 mac pro with unsupported upgrades so any 'wonkiness' I attributed to that.

This week it took 3 reboots and an unplugging of the power cable for a few minutes to get the system to boot without the SIL flashing. Then the following day it will not boot at all. Constant steady flashing (single pulse) SIL.

Dug around in archives here and did some reading. Removed the RAM trays, gave the internals a good blow out (minimal dust), removed RAM sticks and reseated 2 (left all the others out), reseated RAM trays. RAM LEDs flash on once at boot then stay off (no errors) and the SIL still flashing.

So my next understanding is the power supply. Question is, how do I test? How do I access it to remove?
Or the onboard battery. Where is that? How do I access and remove?

Please see video for evidence of what I'm seeing.

 

[madmac66]

I should also say my son has a MacPro 5,1 if I am able to use any components from that machine to test (power supply or battery). If, of course, they are compatible.

Thanks

 

[DeltaMac]

The battery (a CR2032 "watch" battery) should sit on the logic board, directly above the video slot #1, so you should see it if you remove the Geforce graphics card that you have in slot #1.

 

[tsialex]

I should also say my son has a MacPro 5,1 if I am able to use any components from that machine to test (power supply or battery). If, of course, they are compatible.

Thanks

No internal parts besides hardisk and the GPU is compatible with a MacPro4,1/5,1.

MacPro3,1 is only compatible with itself, while MacPro1,1 is compatible with 2,1 and MacPro4,1 with MacPro5,1.

 

[madmac66]

The battery (a CR2032 "watch" battery) should sit on the logic board, directly above the video slot #1, so you should see it if you remove the Geforce graphics card that you have in slot #1.

Thanks. Found it, removed it. Noticed it is a CR2032, not the original BR2032. Would this matter? Is a BR preferable over CR battery?

 

[tsialex]

Thanks. Found it, removed it. Noticed it is a CR2032, not the original BR2032. Would this matter? Is a BR preferable over CR battery?

Yes, it matters. CR2032 chemistry formulation tolerates up to 55ºC, while BR2032 is up to 85ºC. The RTC battery holder is exactly below the GPU heatsink, CR2032 fails in weeks.

You can get Panasonic BR2032 from Mouser/Digikey/etc. Buy for all your desktop Macs.