Casio Oriental Maestro AT1, Service Manual

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Electrical
Current Drain with 9 V DC:
No Sound Output
260 mA
±
20%
Maximum Volume 930 mA
±
20%
with key C3 pressed in Synth-Bass tone and effect No. E-9
Split: On, Layer: On, Oriental scale: On/Cent
Song memory: Play, Volume; maximum, Touch: maximum
Line Output Level (Vrms with 47 K
Ω
load each cannel):
with key F2 pressed in FSynth-Bass tone 2480 mV
±
20%
Phone Output Level (Vrms with 8
Ω
load each channel):
with key C3 pressed in FSynth-Bass tone 97 mV
±
20%
Speaker Input Level:
with key C3 pressed in FSynth-Bass tone 2240 mV
±
20%
Minimum Operating Voltage: 6.3 V
REPLACING THE DSP (HG51B155FD)
Note: To increase productivity ,the DSP HG51B155FD is sticked on the main PCB with a double-side
adhesive tape, then its leads are soldered.
Remove the DSP according to the following procedures.
1. Prepare isopropyl alcohol and a flat IC desoldering machine (Spot Heater HS-600).
2. Apply plenty of the alcohol to the adhesive tape from the reverse side of the main PCB. (Fig.1)
There is a hole on the PCB just under the LSI, and the adhesive tape can be seen through the hole.
3. Leave it more than one minute so that the alcohol weaken adhesive power fully.
4. Using a proper size of nozzle, apply heat to leads of the LSI with the desoldering machine.
5. Grasp the LSI with tweezers, and using gentle force vibrate the tweezers to feel melting solder. (Fig.2)
6. Remove the LSI after meltingsolder at every leads wholly.
Alcohl
Spot Heater HS-600
Fig.2 Fig.1
HG51A115A
LSI-S