DOM MB V5 Diagnosis page

Board ID:

V5 00686

Source:

Micheal Harris

Symptoms:                            

LED "no light" test gives large light pulse, instead of zero light.

Analyst(s):

G. Przybylski

Analysis Procedure(s):

Measured Vout with Vc = 0, and Vc=2.5V. Output 31.7V, and 15.7V respectively.
Measured Vref of U6 (by inference from V6-4) = 1.95V. 
[With new Vref, the range formulas predict the observed max and min.]
Tests imply that U6 (TPS61245) is faulty
Passes room temperature STF test suite.

Root cause:

Faulty LED power supply switcher

Mitigation:

Replace faulty U6. Retest.

Disposition:

Repaired.

Any Other Information:

Traveler