DOM MB V5 Diagnosis page

Board ID:

V5.0L 000530

Source:

George Chao

Symptoms:

August 6: Communications failoure out of HASS
Suffered fall to the floor during handling in the 'cemetary...'
October 21: Boot failure at beginning of cold

Analyst(s):

G. Przybylski

Analysis Procedure(s):

August 6: Reload CPLD firmware; Reload EPC8 firmware/software; Reload flash file system.
Repeated boot and start of STF. No failures noted.
Passed room termperature STF Suite.
October 21: Inspection of U8 reveals suspicious soldering quality. Recommend replacement of U8, and more strenuous boot testing.
Helen replaced U8 12/1/04.
Ran approx. 2000 reps of periodic reboot test  while cycling temperature between -55°C, and +65°C;  No boot failures.
Ran temperature profile from -40
°C to -75°C;
Serial ADC failures on many channels from -45
°C to -60°C.
Local coincidence loopback test failures from -65
°C to -75°C.

Root cause:

Probable faulty U8, or U8 soldering

Mitigation:

Component replacement, with thorough testing

Disposition:

In spite of suffering a fall, probably OK for deployment.

Any Other Information:

Traveler  August 6, 2004
Traveler    October 27, 2004

U8 Footprint showing discoloration

Soldering of U8 30

Other views

U8 View
Another U8 view
Yet anotehr U8 view