DOM MB V5 Diagnosis
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Board ID:
V5 00753
Source:
George
Symptoms:
No on-all Boot failure during end of HASS (i.e. cold)
Fails to boot at all, at any temperature.
Analyst(s):
G. Przybylski
Analysis Procedure(s):
Discover that 3.3V reads
1.1V.
After U8 replacement, ran a boot test on the board:
Reboot about every 2 minuutes from 12/3 ~16:00 to
12/6 ~0900, while running a -55°C to +65°C
ramp profile in the fridge.
No boot failures throughout the weekend.
Ran temperature profile from -40°C to -70°C:
No STF failures below -70°C.
At 70°C, ATWD 0, Ch1 baseline fails
At -75°C, Memory 0 Long test fails,
ATWD 0, Ch0 and Ch1 baseline fail
Root cause:
Suspected that U8 might be bad.
Demounted U8. See pix
Mitigation:
U8 faulty, or the soldering of U8 faulty. See pix below.
Disposition:
Replacement of U8, along with strenuous reboot test over a long
period of time.
Mainstream
Any Other Information:
Traveler
Traveler September 27 -- Final
Decembrer 6
