Canon SPEEDLITE 540EZ Service Manual page 67

Part 3: Repair Information
3.4 FA Aperture adjustment
<Purpose>
To adjust the f/stop information (voltage) output to the camera according to the
photosensor intensity during pre-flash in the A-TTL mode.
<Standard>
The following outputs shown in the table must be output under the following
conditions.
) Apply a voltage of 1.20V to the EFID terminal.
2) Use the standard reflector.
3) Use new batteries in a fully charged state. (20 seconds after the red lamp
has lit)
Terminal voltage (mV)
375
-7
7 ara recede '5 mV
525 | -------}-----
BOO paccidss pe secs an Rated voltage: +75 mV
-37 mV
GToi howe emer sate edla mat
150! Pesessceb esas sendh eee ee ale
825: | ---=---}----}----s-- = =~ 4--_ 4-2
900 | --
ZOOM position Shooting distance (m) !>
35 mm | 0.81 [ta | 1-61 [2.28] 3.22] 4.56] 6.44] 9.11
— Ti
Set A distance Set B distance
Figure 3-11 FA f/stop Ratings (voltage)
3-16