Philips CD950 - Page 39

CHECK OF THE PHOTODIODES
pee
power on
CHECK OF LASER SUPPLY
The laser, the lasersupply plus the monitor diode form a feedback system.
Signal depends on Distance lens «>
IR LED of remote control
T-23366A
A defect in the lasersupply may result in the destruction of the laser. If, in that case, the laser is replaced; (= complete
C.D.M.-unit) the new laser will also become defective. However, it is impossible to check and repair a feedback system if
a link is missing. For this reason the laser supply can be checked with teh replacement circuit for laser assembly.
After opening SK, the led will emit more light for a short moment.
CHECK OF CDM9
S current | Test disc
= voltage | 5A play
across
R3000
TH
| Oo |
Le eae 56<mV<76
Pee
WARNINGS
1. Never disconnect flex when power is on.
2. Laser power is adjusted during the production process
and may not be readjusted.
The leetback system sees to 4 thal tne
same amount of current flows through the LEO
When SK is open and when SK «closed
the LEO ermts ithe ght
T-23366B
SPE
Si
Bi
Bl
Bi
BL
Filter
CO P