23
8.2.1 Troubleshooting
P816
Figure 8-5
8.3 CD
Main
Board
The CD main board is built around the compact disc
mechanism MAR1250 and a loader 1250. The CDM delivers
diode signals and an unequalised high frequency signal. These
signals are necessary inputs for the decoder CD10. Based on
these signals the decoder will control the disc. The decoder is
able to control the sledge, focus motor, radial motor and turn
table. When everything is "locked", the decoder delivers a
digital output according to IEC958 standard, subcode to the
microprocessor and I2S for reproducing analog audio signals
by means of a D/A converter.
The microprocessor controls the CD10 and is slave of the
master processor on the CDR main board in the DR2100. Both
processors communicate via a DSA connection (data, strobe
and acknowledge).
YES
Connect the mains inlet to a mains
isolated variac
Check the functionality of the following components :
F820, R819, C820, L820, D802
Power supply OK?
Power supply unit OK
OK
NO
NO
OK
OK
Check the path of the other faulty voltage(s)
Power supply is OK
Check : - CDR main board
- Main u-com board
- C
- REAR TERMINAL board
D main board
Check DC voltages
5VM, 5VU, +12V, -8V
Check : Waveform of D804 at anode
R830, R825, R826, R890 is not shorted.
Q825 works properly.
Disconnect power supply unit from CDR main board,
Main u-com board and REAR TERMINAL board.
Connect resistor 1k ohm at pin 3 of conn. J852 and ground
t
Check DC voltages
These voltages might be somewhat higher than specified
5VM, 5VU, +12V, -8V
OK
+5VM : check D856, C857, L856, C859, Q851
+5VU : check CR890, D866, L867, Q852, C853, C858, C867
+12V : check D866, C867, L867, Q861, R861, R862, C863
1.41 x Vin AC
Turn input voltage up and check voltage across C821,
this voltage should be
NO
OK
Chec
8.2 Power Supply Unit P816
k fuse F820 and
replace if necessary
OK
Load on secondary output
Overvoltage protection : L832, D814, C814, R814, R815, R816
Oscillator voltage on pin 10 of Q810 :
check C802, R810 replace Q810
Drive circuit : gate voltage of MOSFET Q825
components R812, R813, C813, R825
Regulation circuit
- Measure voltage on pin 6 of Q810
with oscilloscope
- If > 2.5V check the regulation circuit : Q810, D881
R881- R885, C881, C882, R804 - R806, R809, C804, C809
Check :
Содержание DR2100
Страница 43: ......
Страница 49: ...2 11 2 12 CD top CD MAIN BOARD TOP VIEW CL 96532086_019 eps 080999 2 3 PARTS LOCATION...
Страница 52: ...2 17 2 5 ELECTRICAL PARTS LIST...
Страница 53: ...2 18...