DOM MB Diagnosis page

Board ID:

Rev 5.0 SN 0588

Source:

From STF testing crew

Symptoms:                            

Fails Local Coincidence Loopback tests

Analyst(s):

G. Przybylski

Analysis Procedure(s):

Load and execute ?DO lctestboth wait20ms LOOP, with terminated pair ports,  and probe LC circuit.
Waveform at R75 (driver) OK.
Waveform at TP10 inverted, when should be flat line
Waveform at TP3 flat when should resemble  waveform at R75.
Lifted lead of T3.  TP3 signal reappears.  Replace T3 and run STF tests with favorable results.

Root cause:

Found faulty T3; no evidence of solder bridges.

Mitigation:

Replace defective part, and retest. Run complete STF.

Disposition:

Sent to Helen for clean-up,  and rerouting into the normal production queue.

Any Other Information:

none