Electrical Adjustment - Sony PRS-500 Service Manual

PRS-500
Vcom Voltage Adjustment
Vcom voltage for the display panel varies for each panel. Vcom
adjustment is required when replacing a board or panel.
Preparation
Voltage is generated only when the screen is changed, so the
adjustment needs to be performed while changing the screen. Use
the slideshow function to change the screen sequentially.
1. With the "Settings" tab in the menu selected, press the [ENT]
button or the [0] button.
2. With the "Slideshow" tab selected, press the [ENT] button or
the [3] button.
3. Set "Turn On, Slide Duration 05 seconds", and press the [ENT]
button on OK.
Procedure
1. With the "Pictures" tab in the menu selected, press the [ENT]
button or the [9] button.
2. Specify a desired screen, and press the [ENT] button to check
that the slideshow starts.
3. Observe the negative side of C1666 on an oscilloscope (refer
to Fig.2), and use RV1601 to adjust the voltage that is generated
when the screen is changed so that it satisfies the standard.
Standard: Written on the flexible card wire of the display panel with
a marker. (–1 V to 2.5 V)(Refer to following Fig.1)
(In case of Fig.1: The value of Vcom is 1.83 V.)
12
SECTION 5

ELECTRICAL ADJUSTMENT

Fig.1
500 mV/DIV, 400 ms/DIV
LOCATION OF C1666 AND RV1601
MAIN BOARD
(SIDE A)
RV1601
C1666
IC1606
IC1607
1.3 Vp-p
Fig.2
IC201