_ DEC-O-LOG for H7214

_ DOL, H7214-F001, Regulator, Jan 91

PROBLEM: The formation of metal dendrites (metal migration) on the 
control hybrid (Z1) due to exposed silver pads.  The symptoms in 
systems will be system crashes due to DC LO when power supply output
falls to zero.  The problem may appear as a hard fault or an intermittent
depending on the extent of metal migration on the hybrid.

FIELD EFFECTIVITY: Upgrade all H7214-A regulator spares and any 
customer equipment bearing serial numbers in the range "ME930XXXXX"
through "ME017XXXXX" for 6XXX systems and serial numbers prior to
BTO4030034 in 9XXX systems or in systems which exhibit intermittent
shutoff behavior in the H7214 regulator.

QUICK CHECK: Check the serial no. on the regulator, and/or visually
inspect the control hybrid for the presence of a tan or light brown
coating.  There are a number of hybrids with silicone coating which
is hard to detect.  The serial #'s of the H7214s with silicone coating
are MEO4114633 thru ME4515960.  Do not replace hybrids with the silicone
coating.  They are adequately protected from contaminants.  H7214s that
have been reparied have a green dot on the power regulator in the upper
left corner above connector "J2".

FCO KIT ORDERING

EQ-01601-01 FCO, Parts 
FA-04931-01 FCO Document