I recently purchased a refurbished T5500, and upgraded the CPUs, installed USB PCI card and AMD 6770 video cards. The machine boots without the second CPU riser installed, but when the riser is in I get the Pb7 (flashin 2,3, 4 and solid amber power) error. I checked the riser pins, pulled the CPU and swapped them, checked the pins on the socket, and everything looks okay. I have tried just about everything mentioned in other posts referencing the Pb7 error, but to no avail.
Original CPU E5606 x2
Current CPU X5650 x2
I replaced the motherboard, and a third riser card. Still cannot use the riser card. The replacement MB had the A05 BIOS, so I upgraded to the A16 BIOS. The processors are matched, 8GB DIMMs are installed on both the motherboard (48 GB) and riser (24 GB). All DIMMs have passed Memtest+ when installed on the MB, and both processors work when installed on the MB.
Same exact issue, except 6x4gb on mb and 3x8gb on riser (which is a supported memory configuration. Definitely not an issue with the cpus or the ram. Also upgraded bios to A16. did you manage to resolve this?
I have the same problem. Motherboard blew up, replaced motherboard and later riser, now stuck in Pb7 when I try to boot with the riser installed. Has anyone made any progress on this?
Any anyone been able to resolve this issue. I'm also getting PB7 error with riser pluged in. Single cpu seems to be working though.
6x4GB on main motherboard, 3x8gb ram on the riser. 2 x X5690
1100 Watt power supply is required. You have a smaller power supply.
flashes the Pb7 error code, which translates to:
ACPI S0, hand off to BIOS control
System on. BIOS not execution. This is the transition state to POST states.
Solid Amber — System fault(Motherboard), but +5VSB Power Supply is good—normal operating state (S0)
BIOS must be updated BEFORE changing CPU.
Pb7 is dead motherboard/cpu
I think it's important to remember that the dual CPU set up is fairly complicated. If everything's not perfect it just won't work. You can read about my personal experiences with this here: en.community.dell.com/.../21016701
It's a hard nut to crack honestly because there's a number of things that it could legitimately be. For me, in spite of the fact that I swapped CPUs and it booted and ran with both there was one that's very slightly damaged and so it was no longer a perfect match. Let me make this clear, my CPU was NOT dead. Just very slightly broken and therefore a mismatch.
It wasn't badly broken as I ran for some time with each of them individually with no issues at all, but it seems that it doesn't take much, just a little bit of damage to throw the Pb7 error code.