Laser Power Supply Failure During Exposure

Itai Peperovich
07-May-01

Description

A recent report from the production line states that a machine in a very advanced stage was suddenly having "laser power supply fail" problems during exposing. A large group of diodes failed to make calibration. To recover from this problem, a complete start up was required.
The start up helps sometimes, but the problem returned.

Cause

After investigation, we discovered that the nuts on the cables from the (-5 V) power supply to the main M.B were not tightened securely inside the L-box. Due to the loose nuts, the -5 V did not reach the M.B therefore causing this failure.

We are uncertain if any other L-boxes with the same problem had left CSIL. Therefore, when facing the same symptoms, please check the -5 V nuts on the power supply cables from both sides (please see the pictures below).

Checking the cable connections on the power supply side

Checking the cables connections on the M.B. side.