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Brother DP-525CJ Service Manual: Fig. 2.23 Lcd Drive Voltage Generation Circuit (minus Voltage Vee); Fig. 2.24 Lcd Drive Voltage Generation Circuit (plus Voltage Vee)

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THEORY
Electrical
9.3.
LCD Drive Voltage (VEE) Generation Circuit
The polarity of the LCD drive voltage (VEE) differs according to the LCD module.
Fig. 2.23 shows the circuit for the LCD module driven by the minus VEE voltage. The
+5 VDC source voltage is switched continuously by the 20 kHz pulses from CBIC (#8) to
energize L5. The reverse voltage generated by L5 is rectified by D6 and regulated by
ZD5. The ZD5 determines the VEE voltage (about -16 V).
The LCD module driven by the plus VEE voltage uses the circuit shown in Fig. 2.24.
The +24 VDC source voltage is switched continuously by the 90 kHz pulses from CBIC
(#8) to energize L2. The voltage generated by L2 is rectified by D5 and regulated by
ZD4 and ZD6. The ZD4 and ZD6 determine the VEE voltage.
VEE voltage is adjusted by turning VR1.

Fig. 2.23 LCD Drive Voltage Generation Circuit (Minus Voltage VEE)

Fig. 2.24 LCD Drive Voltage Generation Circuit (Plus Voltage VEE)

2-22
SERVICE MANUAL

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  • brian aaron Jan 27, 2017 03:48:
    1-26-2017
    ​I have a brother dp 540cj and it has a built in diskette drive.
    I have a ibm thinkpad latop. I connected a Memorex external usb floppy drive to the ibm thinkpad laptop. i'm copying 3 files from the ibm thinkpap (notepad) to the square 1.44 mb diskette. no problem, the 3 files were copied to the diskette.
    ​I turn on the brother dp 540cj, select file manager, insert the square diskette. the brother dp 540cj open only the file names on the disk. I try to open word text on either of the 3 files on the disk and the brother dp 540cj don't open the word text in any of the 3 files. I have been trying for several days to open the word text on the files using the brother dp 540cj and don't have any further instructio​ns for this problem. I tried saving the file names to all coding - Unicode, ansi utf-8 and can't fix the electronic problem.
    m​y email address is snowwash@j​uno.com