Troubleshooting - Sam4s ER-390 Series Service Manual

8 Troubleshooting

8-1. Power Problem
Power
Problem
Power Out
Ok? On Trans
Y
Power VDISP
(+30V) Ok?
Y
Power VDRV
(+24V) Ok?
Y
Power VPRT
(+8.5V) Ok?
Y
Power VCC
(+5V) Ok?
Y
1. Check the MC7805(U5)
2. Check the Capacitor(C50)
3. Check the VCC whether
it is short or open.
End
SAM4S ER-390 SERIES
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1. Check the Power Cable
N
2. Check the Power S/W Board.
3. Check the Power Transformer.
1. Check the Bridge Diode(D4~D7) on Main Board
N
2. Check the VDISP signal whether it is short.
1. Check the Fuse (FU1) on Main PBA
N 2. Check the Bridge Diode(BD1) on Main PBA
3. Check the VDRV signal whether it is short.
1. Check the IC34063 (U4)
2. Check the TR1010,708 (Q10,Q6)
N
3. Check Generated Frequency
4. Check the VPRT whether
it is short or open.
N Power VPH
(+8.5V) Ok?
N
Y
1. Check the CPU P8.7
(VPH_ONOFF) Port
2. Check the KSA1010,MMBT2222
(Q11,Q16,Q17) on Main Board.
3. Check the VDRV signal whether it
is short.
8-1