Pioneer PDP-42A3HD Service Manual page 92

1
Basic Inspection
Does Not Boot after Power-On or System Reset
A
Preliminary Checkpoints
The system clock 27MHz must be stable during the System Reset or the Power On Reset.
However, if X-TAL is defective, the clock may not become stable until RESET is released.
To check reset timing, turn the main power off and back on, and check if the following waveform is maintained.
B
Reset timing promlem
Check the reset signal of
C Flash and Pin1 of U281
Check the soldering status
of U40(Flash Memory)
D
and U62
Check the soldering state of
EFPROM
E
Useful Tips
1. The CPU have two 12C for system controller.
One is communicate with system 12C(TDA10046) and the other is communicate with serial EFPROM for storing data.
2. When the system will not operate even though the basic inspection results were normal, check Flash Memory which
contains channel data and program contents.
3. Additionally check for Local DATA and Local ADDRESS buses between CPU and Flash Memory.
4. When replacing parts, be careful of static changes from the tip of the solder iron that can easily damage the parts.
Also, check for assembly condition, soldering condition, or for incorrect or reverse insertion of parts.
5. If the problems are caused by CPU, change CPU board and download Serial Number.
F
T17
92
1
2
Does Not Boot after
System/Power-On Reset
Check the Reset and
clock timing of CPU
OK
Check the communication
between DTT and
digital board
OK
NG
Check Flash Memory
OK
NG
Check the 12C Line
(Pin 6, 5 of U31)
OK
Check for other defective
modes
PDP-42A3HD
2
3
Waveform 2
Waveform 4
27 MHz Clock problem
Check the soldering status
of X-TAL(Y261) and U261
NG
Check the soldering status
Check the digital board
Waveform 5
NG
Check the waveform CS
and OE of Flash Memory
Waveform 6
Ch1:SLC, Ch2:SDA
3
4
of JP282.
T17
4