Table of Contents
Advertisement
POWER SUPPLY CIRCUIT
The power supply circuit regulates two constant output voltages VDD (+5.0 V) for the CPU and the oscilla-
tor, and AVDD (+4.8 V) for the analog circuit.
D101
ON
DC +9 V
OFF
Input
Nature of Trouble
No power
No sound at all
Certain keys or switches
do not function
A certain key or switch
does not function
Power Switch
DG
DG AG
TROUBLESHOOTING
Faulty Block
Power supply circuit
Power switch
Power jack (J101)
Power Amp (IC101: LA4598)
CPU (LSI201: MSM6387-13)
Oscillator
Key and switch matrix
CPU (LSI201: MSM6387-13)
Key and switch matrix
Q101
R116
2SD1858Q,R
R101
Q102
2SC1740SQ
DG AG
Faulty Q101. Replace Q101.
Faulty D102. Replace D102.
Poor contact. Clean the contacts.
Open J101 or poor soldering. Replace
J101 or resolder.
Open or shorted IC101. Replace IC101.
Faulty LSI201. Replace LSI201.
Faulty Q301. Replace Q301.
Open X301. Replace X301.
Open circuit on KO or KI line.
Replace keyboard PCB assembly.
Faulty LSI201. Replace LSI201.
Dust on the contact.
— 7 —
VC (+9 V)
VDD (+5.5 V)
AVDD (+4.8 V)
D201
R208
Cause/Remedy
Hide quick links:
Advertisement
Table of Contents
Need help?
Do you have a question about the CTK-50 and is the answer not in the manual?
Questions and answers