GEM Realpiano Rp700 DIGITAL User manual

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Index
Soldering point.
Male connector.
Female connector.
M/F faston connector.
Test point.
Supply voltage. Logic supply ground.
Analog supply ground.
Chassis ground.
Earth ground.
Flag joined with one or more flags
GENERALMUSIC S.p.A. Sales Division: 47842 S.Giovanni in Marignano (RN) ITALY - Via delle Rose, 12
Phone [phone] - Fax [phone] - Internet: www.generalmusic.com
Repair Instructions & Timing Table.
Opening & Keyboard Disassembling Instructions.
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Block Diagram, Mains Filter Board Schematics.
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CPU & Sound Generator Board Schematic.
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Keyboard Interface, In/Out, Controls Panel Board Schematics.
7Power Supply& Amplifier Board, Mains Filter, In/Out Pcb Layouts.
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Controls Panel, Keyboard Interface, Cpu & Sound Generator Pcb Layouts.
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Left, Middle, Right Contacts Board Schematics.
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with the same signal name inscribed.
ATTENTION Observe precautions when handling electrostatic sensitive devices.
Notice
Service must be carried out by qualified personnel only. Any tampering carried out by unqualified personnel during the guarantee period
will forfeit the right to guarantee.
For a correct operation of the instrument, after having switched off, be careful to wait at least 3 seconds before switching on again.
To improve the device's specifications, the schematic diagrams may be subject to change without prior notice.
All components marked by this symbol have special safety characteristics, when replacing any of these components use only
manufacturer's specified parts.
The (µ) micro symbol of capacitance value is substituted by U.
The (Ω) omega symbol of resistance value is substituted by E.
The electrolytic capacitors are 25Vdc rated voltage unless otherwise specified.
All resistors are 1/8W unless otherwise specified.
All switches shown in the "OFF" position. All DC voltages measured to ground with a voltmeter 20KOhm/V.
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SERVICE MANUAL
code 270290
Power Supply & Amplifier Board, Phones Board Schematics.
Spare Part List.

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A B C
DHOW TO OPEN THE RP700 CABINET:
A) Remove the top cover unscrewing the 5 screws on rear panel, pull the
cover towards you and lift it up.
B) Slide the keyboard cover on rear position and unscrew two metal suppor-
ts on sides; then slide the keyboard cover full towards you and remove the
glued pastic caps on centre of two Lx & Rx black rack guides.
C) Slide again on rear direction the keyboard cover until the wheel link bar
rise the opening of removed plastic caps and lift up the keyboard cover from
cabinet.
D) Moreover, to remove the keyboard front panel, unscrew the 2+2 fixing
screws on sides.
E) To remove the keyboard group, unscrew 16 fixing screws from the bottom
cabinet and lift up the keyboard, after having disconnected the 2 flat cables
HOW TO INSPECT THE KEYBOARD AND TO REPLACE
THE SINGLE KEYS:
F) Remove the keyboard group from cabinet as described on point E);
then place the keyboard on flat surface to check all mechanical & electrical
parts.
- To replace the single white & black keys, pull each key on arrow direction of
F1 figure; then turn up the single key from fulcrum as shown on F2 figure.
-To mount the single white & black keys on keyboard take care to apply the
leaf spring between the hammer corner and key back side; then place and
move each key on keyboard frame following the arrows opposite direction of
F2 figure.
F1 F2
LEAF SPRING
E

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RP700 REPAIR INSTRUCTIONS
This model doesn't provide an autotest procedure, then in case of electr. fault we suggest to proceed on its repairing as follows:
[1] Switch ON the Piano and check if the led on cabinet is lighted and the led of Grand Piano button is flashing after some seconds from the
switch ON phase.
[2] Then, after having opened the RP700 cabinet, check the presence of supply voltages on power board ass.y (+5V, +/-12V, and +/-20Vcc for
power amplifiers TDA 7296].
[3] POWER ON/OFF, MASTER RESET, MUTE TIMING check
Using dual channel oscilloscope, try to visualise +5V Power Supply, VOK, Reset , Mute signals timing during RP700 POWER ON, as by timing 1;
Starting from the POWER ON event the RP700 remains in Reset condition until the +5V Supply rises 4.75V value on IC17 pin2 (MAX709)
setting the active VOK (after 200ms) and Reset controls; the VOK and Reset signal are connected to pin 209 and to pin 206 of DRAKE Chip
(IC9); the RST delay should be >60uS refer to VOK rise time . The Mute signal is controlled by RP700 O.S., after the finish of start-up phase,
it actives the analogue signals on IN/OUT's plugs and on speakers, through RL2 & RL1 relais of 731083 power supply board.
[4] MAIN (CPU) BOARD ASS.Y CHECK
The RP700 Digital Piano provides a main (CPU 761300) board ass.y that requires a specific knowledge of DRAKE (Dsp Risc Advanced Keyboard
Engine) custom chip, no easy to extend and to check outside of GM factory; so, we suggest the replacement of main board when the RP700
doesn't work at all or work partially on sounds generation and on keys & controls playng. In any case the following informations can be useful
to locate a specific problem on main board, before to replace it:
[4.a] MASTER & BIT CLOCK
The Master clock (MCLK) of main board is generated on DRAKE chip (pin 160-161) with XT1 quartz oscillator (fo =11.2896MHz)that you can
check by oscilloscope on pin 2 IC19 as by fig. 1: The Bit Clock (BCLK) of main board is generated inside DRAKE chip (pin 230) dividing 4 times
the MCLK; its frequency is: =2.8224MHz that you can check by oscilloscope on pin 26 IC19 as by fig. 2:
[4.b] CONTROLS PANEL BUS TIMING
It is generated by DRAKE chip (IC9) through the RP700 O.S.; the relative signals can be checked by oscilloscope as shown on timing 2.
[4.c] CPU-KEYBOARD INTERFACE TIMING
It is generated by DRAKE chip (IC9) through the RP700 O.S.; the relative signals can be checked by oscilloscope as shown on timing 3.
[4.d] DRAKE - DAC SERIAL BUS TIMING :
It is generated by DRAKE chip (IC9) through the RP700 O.S.; the relative signals for the D-Sigma stereo D/A converter can be checked by
oscilloscope as shown by timing 4.
[4.e] If the previous checks on main board are OK, the RP700 has to generate sounds; to verify this condition, press the SOUND DATA UP
& DOWN buttons at same time to active the DEMO function with the GRAND PIANO led flashing. Now a sound pattern sequence should be
played by CPU board, in line with the O.S. release installed; in absence of sound from speaker verify with oscilloscope the presence of the
audio signal on CN7 connector, pin 14, 16. At last try to reload the O.S. on Main board as by following instruction.
[5] OPERATING SYSTEM UPDATE
The O.S. of main board is preload into (IC2) NAND FLASH Memory from GM factory; the 256Kbit NAND FLASH Memory is formatted and
written with O.S. pattern using PC system with RS232 serial port and hardware interface kit.The update of O.S. must be taken out from
qualified Personal; it requires the opening of RP700 cabinet, the shift of J1 Jumper from E2 to UART position on CPU board, and the proper
installation of an interface kit on main board CN1 connector; to execute this operation, please refer to the separate document O.S. update
installation instructions procedure.

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