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TROUBLESHOOTING TABLE
Trouble
Faulty Block
Checkpoint
No Powr ON
(TUNING lamp does not
light at all)
Power Circuit
T1 collector voltage (+9V)
T4 emitter voltage (+5V)
T5 emitter vottage (+5V)
Power switch
Switch contact
Power jack
CPU (pPD78C1 1 G-18)
Pin 56 (Should be High)
No sound at all
Reset Circuit
Refer to wavelorm O
12 MHz Oscillator
c P U ( r c 1 3 )
Pins 59-2 should output pulses
when the horn is blown.
Pin 17 should output pulses When rtA
blown (Refer to waveforms (4) and (5) )
VCA Circuit
VCF Circuit
Waveforms @ano @ .
DACl
T5 emitter voltage should rise when the
horn is blown.
Power Amp (LA4182)
Pins 2 and 11 should output waveforms
when the horn is blown.
Speaker
No reverb etfect
Sampling Circuit
Waveform@
DSP (rC3)
Data bus, Address bus
Pins 48 - 60 should output pulses when
played.
Sampling signals BltltanO BftlH
(refer to waveforms (Q) and Qf )
Sample/Hold Circuit
Waveform @
Filter Block
Power ON Mute Circuit
c P U ( r c 1 3 )
Pin 15 should output waveform Ot,
Power ON.
R A M ( r C 1 )
REVERB VR
Certain key(s) do(es) not
work
Key contact
Open circuit on PBO - PB4
or PC1 - PC3 lines
- 2 5 -
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