228-90095F
3
7.1.3 Changing the gain of operation amplifier
After the mirror M1 is fine-adjusted as described in Amendment F in this
Service Manual, optical energy may become saturated. Check the energy
after adjustment. If the energy is over the standard level, lower the gain
of the operational amplifier by the procedure described below.
7.1.3.1 Checking the light intensity
After the optical system is adjusted using the added jig (for fine adjustment of M1),
the light intensity may increase by several percent. This may cause saturation of
light intensity due to a variation of the lamp or optical element. When no measure
has been taken for the pre-amplifier (PB-1 ASSY), attach a new D2 lamp and check
the light intensity by the procedure described below. If the light intensity is over the
standard level
*1
, lower the gain resistance of the pre-amplifier by 7 % using a jumper
wire and solder. This modification is unnecessary for instruments where a
pre-amplifier for micro cells
*2
is attached.
＊ 1: The light intensity standard (upper limit) differs according to the type of the
MAIN board (PCB, SPD20-MAIN ASSY); new or former. The new and former
boards can be distinguished by the BOARD identification no.
*3
serigraphed on
the MAIN board.
＊ 2: The gain of the pre-amplifier on the RE side is maintained at a low level on
instruments where a micro cell is attached. Thus, the light intensity does not
saturate even after the optical system is adjusted using the added jig (jig for fine
adjustment of M1), leaving enough allowance. Therefore, modification is
unnecessary.
＊ 3: How to distinguish new and former MAIN boards
They can be distinguished by the BOARD identification no. serigraphed on the
MAIN board.
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