Jvc KSFX 725 R Service Manual

Page 1

1-2 KS-FX725R ! Burrs formed during molding may be left over on some parts of the chassis. Therefore, pay attention to such burrs in the case of preforming repair of this system. Safety precaution

Page 2

1-3 KS-FX725R Press the eject button in the lower right part of the front panel. Remove the front panel assembly from the body. 1. Removing the front panel assembly (See Fig.1) Prior to performing the following procedure, remove the front panel assembly. Release the four joints a on both sides of the front chassis assembly and remove the front chassis assembly toward the front. 1. Removing the front chassis assembly (See Fig.2 , 3) Disassembly method

Fig.1 Fig.2 Fig.3 Front panel assembly Eject button Joint a Joint a Front chassis assembly Front chassis assembly Heat sink Joint a Joint a

Page 10

1-11 KS-FX725R Remove the band attaching the wire to the head. Remove the two screws D, the head and the head support spring. Remove the pinch arm spring from the tape guide. Remove the tape guide and the pinch spring arm. 1. 2. 3. 4. Removing the head / tape guide (See Fig.18 and 19) Remove the belt at the bottom. Remove the two polywashers on the upper side. Pull out each flywheel assembly downward. 1. 2. 3. Removing the flywheel assembly (F) & (R) (See Fig.20 and 21) When reattaching the pinch arm spring, set both end of it to the pinch spring arm ( remarked r). CAUTION: When reattaching the head, set the wires into the groove of the tape guide (Fig.18). CAUTION: It is not necessary to remove the slide chassis assembly. REFERENCE: It is not necessary to remove the slide chassis assembly. REFERENCE: Fig.19 Fig.21 Fig.18 Fig.20 D Slide chassis assembly Head Tape guide D Pinch arm spring Head Head support spring Tape guide Pinch spring arm Slid chassis assembly Flywheel assembly (F) Flywheel assembly (R)Belt Polywasher Polywasher Flywheel assembly (F) Flywheel assembly (R) r r

Page 28

1-29 KS-FX725R LC75823E (IC651) : LCD Driver 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 S1 S2 S3 S4 S5 S6 S7 S8 S9 S10 S11 S12 S13 S14 S15 S16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33S48 S47 S46 S45 S44 S43 S42 S41 S40 S39 S38 S37 S36 S35 S34 S33 64 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49 S17 S18 S19 S20 S21 S22 S23 S24 S25 S26 S27 S28 S29 S30 S31 S32DI CL CE OSC Vss VDD2 VDD1 INH VDD COM3 COM2 COM1 S52 S51 S50 S49 1. Pin Layout & Symbol 2. Pin Function Pin No. 1 to 52 53 to 55 56 57 58 59 60 61 62 63 64I/O O O -- I I I -- I/O ISegment output pins used to display data transferred by serial data input. Common driver output pins. The frame frequency is given by : t0=(fosc/384)Hz. Power supply connection. Provide a voltage of between 4.5 and 6.0V. Display turning off input pin. INT="L" (Vss) ----- off (S1 to S52, COM1 to COM3="L" INT="H" (VDD)----- on Serial data can be transferred in display off mode. Used for applying the LCD drive 2/3 bias voltage externally. Must be connected to VDD2 when a 1/2 bias drive scheme is used. Used for applying the LCD drive 1/3 bias voltage externally. Must be connected to VDD1 when a 1/2 bias drive scheme is used. Power supply connection. Connect to GND. Oscillator connection. An oscillator circuit is formed by connecting an external resistor and capacitor at this pin. Serial data CE : Chip enable interface connection to the controller. CL : Sync clock DI : Transfer data Symbol S1 to S52 COM1 to COM3 VDD INH VDDD1 VDD2 Vss OSC CE CL DIFunction