Assembly And Disassembly Precautions - Canon SPEEDLITE 540EZ Service Manual

Part3: Repair Information
1. REPAIR PREPARATIONS
1.1 BLEED the MAIN CAPACITORS!
Even after a full power flash discharge, a charge of 70 to 90 volts remains on the
main capacitors in the flash circuit. Therefore, always bleed the capacitors
before starting any repair.
(1) Set the flash head to the normal position (bounce 0° position).
(2) Peel off the rubber cover around the bounce lock knob.
(3) In the figure below, you can see the main capacitor (+) terminal. Short this
terminal and the shoe GND terminal with a bleeder resistor,
Flash head
Bounce lock knob Main capacitor (+)
Figure 3-1 Capacitor Bleed Points
1.2 Assembly and Disassembly Precautions
The structure of the flash unit is basically the same as that for the 420EZ and
430EZ. So, the same disassembly procedure is used. Numbering in the figures
(1), (2), ete. indicates the disassembly order. When assembling, follow the order
of these numbers in reverse.
1.3 Tools Lists
Tool Name: Used for:
Light Meter (Flash Meter) Adjustment of M G-No.
Transistor Pack All adjustments.
Multi-meter (voltmeter) Full charging voltage adjustment, pilot lamp
lighting adjustment
Tripod Adjustment of FA f/stop, M G-No.
Standard Reflector Adjustment of FA stop, M G-No.
Multi-camera Tester (EF8000/5000/500) Disassembly
Camera (EOS1-N) Adjustment of M G-No.
Lens (EF 50 mm #/1.8) Adjustment of FA fstop
3-1