Troubleshooting - Sharp ZL-6500 Service Manual

ZL— 6500
2-7. Troubleshooting
Error message or trouble symptom
Failure in the system ROM (27256)
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25;
Failure in the A15 or A15' signal line (open line or line touch)
RAM NO.1 FAULT Failure in the RAM1 (TC5565)
Failure in the address decoder (74LS138)
Failure in the RAM1 signal line
Failure in the VB circuitry (peripheral of 2SA673A)
RAM NO.2 FAULT
The RAM option (RAM2) not mounted (not a fault)
Failure in the expansion RAM (RAM2)
Failure in the RAM2 signal line.
Failure in the VB circuitry (peripheral of 2SA673A)
DISP ACK IS HIGH ERR
DISP CNTLER DIED
Failure in the DCU (HD614048FD12)
Failure in the DCU ceramic vibrator (CSA6.00MG)
Failure in the 8255
Failure in the display PWB connector or cable
Failure in the REQD inversion circuitry (JC501)
eoeoeee@
e Failure in the character generator (LI-2049)
Open display tube segment
Existence of an inactive dot when all display dots
are driven
When a part of display segments does not activate @ Open display tube grid
e Failure in the grid driver (1R2CO5)
Failure in the DCU g1 thru g13 signal lines.
e@ Failure in the DCU FCUT signal line.
@ Failure in the power supply PWB failament cut circuitry
Failure in the power supply PWB VNG voltage
A faint activation of the dot to be inactive
e Failure in the character generator (L12049)
® Connection failure between the DCU and the character generator
Failure in the —4V line.
When the display contets is at fault
PCU FAULT (BUSY)
PCU FAULT (IBF/ACK)
PCU FAULT (PRINTER)
e Failure in the PCU
e@ Failure in the PCU clock signal ''@PCU"
e Failure in the IR-1W signal line
e
e
Failure in the address decoder (74LS138, main board)
Failure in the PCU signal line.
Failure in the printer itself (motor, main solenoid, home switch, or dot signal)
® Failure in the printer motor control circuitry (VP circuit)
e@ Failure in the dot signal waveform shaping circuitry (JA101, main PWB O4
periphery)
Failure in the printer connector or cable
PCU FAULT (PRINTER)
Failure in the printer itself (color select solenoid)
Do not print in red e
e Failure in the color select solenoid driver (M54567, 1C20)
e
e
Failure in the PCU CC signal tine
Failure in the printer connector or cable
KEY ERR! ERR LINE = HIGH
KEYRCV ERR! PRITY ERR
e@ Failure in the KCU (HD614048FD11)
© Failure in the KCU ceramic vibrator (CSA.OOMG)
@ Failure in the 8255
e@ Failure in the key PWB inverter (40HO04)
@ Failure in the key PWB connector or cable
Failure in key or slide switch action @ Open or touch in the key signal line
®@ Slide switch rubber roller disengagement
® Dirt or foreign matter within the key