To Replace Pa Transistors; Capacitor /Transistor Spacing; Q1 (2Sc2933 Pre-Driver); Q2, Q3, Q4, Q5 & Q6 (Sd1414) - Tait T889 Manual

3.8 Introduction To Servicing
3.4

To Replace PA Transistors

Caution: As the location of certain components in the PA is critical to perform-
ance, it is important that any components removed or disturbed are
refitted in
Do not solder the tabs before torquing down otherwise the device may
Caution:
be broken.
3.4.1

Capacitor /Transistor Spacing

Refer to Figure 3.2.
3.4.1.1

Q1 (2SC2933 Pre-Driver)

Before attempting to remove Q1, measure the distance between the capacitors
labelled "c" and the transistor body (measurement "a") so that the capacitors can
exactly
be replaced in
Note: Be sure to measure between the transistor body and the
of the capacitors.
Position the capacitors labelled "b" hard up against the transistor body.
3.4.1.2 Q2, Q3, Q4, Q5 & Q6 (SD1414)
Position all capacitors labelled "b" hard up against the transistor body.
3.4.2

Replacement Procedure

Desolder the tabs (and grounding clips if an SD1414) by heating with a soldering
iron and lifting away from the PCB with a thin stainless steel spike, or screw-
driver.
Unscrew the transistor and remove the device.
Smear the face of the replacement device with heatsink compound and tighten it
securely (torque setting 6lb-in./0.7Nm) to the heatsink. If you are replacing an
SD1414, remember to fit new grounding clips.
Solder the tabs.
Replace each capacitor as instructed in Section 3.4.1.
02/10/95
EXACTLY
the same position.
the same position.
M889-00
tabs
(not the body)
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