______________________________________________
HARRIS
888-9058-001
WARNING: Disconnect and lockout AC primary power prior to servicing
201
Each gain code has a part number assigned to it. These are shown in the following table:
Figure 8-8 FET Marking Code
Gain Code
Harris Part Number
3
380-0737-003
4
380-0737-004
5
380-0737-005
6
380-0737-006
7
380-0737-007
Once a failed FET is isolated, remove it from the board using the following procedure:
a.
Turn off the bias to all four FETs by rotating the bias control pots counter-clockwise.
b.
Remove the clamp holding down the transistors.
c.
Using a 45 Watt soldering iron with a wide blunt tip, desolder the leads lifting
them with a small knife. It is important to use enough heat to quickly flow the solder
and work quickly so as not to damage the foil.
d.
Remove the old heat sink compound. Use a small amount of solvent, such as Isopropyl
Alcohol, on a swab, being careful not to allow it to run. Do not use sprays of any kind, as
they may dissolve the heat sink compound from underneath nearby FETs.
e.
Re-flow the solder left on the foil where the tab