DOM MB Diagnosis page

Board ID:

Rev 5.0 Serial number 0123 from builder N, with PCB form manufacturer D

Source:

Delivered.    Reported by Azriel Goldschmidt

Symptoms:                            

Reported non-bootable.  Config Boot and Flash Download OK.

Analyst(s):

Thorsten Stezelberger, Gerald Przybylski

Analysis Procedure(s):

Identify bad data pattern in load and verify in SDRAM,  suggesting that data bit 1 not functioning correctly.

Root cause:

Open circuit between memory controller in EPXA1 and SDRAM memory.
A via at the snubber resistor, R361, was way off the center of the pad on the bottom side of the board. See pix.
The Flash memory chip on top of the board obstructs the view of the via.
Another via near the opposite side of the snubbing resistor, on the same net, is in tact, so the board can be recovered by the installation of a jumper wire.

Mitigation:

Probably recovered, after the board loading house and/or PCB vendor quality control department looks over the problem.

Disposition:

Since the fault is so obvious, there is little point in sectioning the via.

Any Other Information:

bad via pix1
bad via pix2