|
Who's Online
There currently are 6043 guests online.
|
Categories
|
Information
|
Featured Product
|
|
|
|
|
There are currently no product reviews.
;
Very quality copy of original service manual, which contains the circuit diagrams, PCB and lists of components, well as recommendation for calibration procedures of device, also everything else, that need for repair, tuning and use this oscilloscope.
All presented copies have high-resolution, so you can view all in detail.
This manual will very useful for simple owners and for repairers.
I recommend these manual, because myself is owner of Philips PM3216 and I need sometimes servicing these oscilloscope (principally calibrating).
Also, these document is an example of excellent design of technical documentation.
;
Excellent printing quality.
A complete and very usefull service manual with all details.
GREAT SERVICE AT VERY LOW PRICE!
A+++++++++++++++++++++++++
;
manual excelente completo , diagramas y esquemas bien presentados y buena calidad de imagen.
;
muy buen manual completo de buena calidad de impresion preciso y detallado , muy útil para la reparación.
;
The service manual is a good quality scan of the Panasonic NV-850, which is electrically identical to the Philips VR 6920, but mecanically just nearly.
1
2
3
4
1.1.3 Focus error amplifier
The photo-detector outputs (A + C) and (B + D) are passed through the differential amplifier and the error amplifier, and (A + C - B - D) is provided from the pin 135 as the FE signal. The low frequency component of the voltage FE is calculated as below. FE = (A + C - B - D) x 8.8k / 10k x 111k / 61k x 160k / 72k = (A + C - B - D) x 3.5 For the FE outputs, an S-shaped curve of 1.5 Vp-p is obtained with the REFO as the reference. The cutoff frequency for the subsequent stage amplifiers is 14.6 kHz.
A
1.1.4 RFOK circuit
This circuit generates the RFOK signal, which indicates the timing to close the focus loop and focus-close status during the play mode, from the pin 70. As for the signal, "H" is output in closing the focus loop and during the play mode.
B
Additionally, the RFOK becomes "H" even in a non-pit area, since the DC level of the RFO signal is peak-held in the subsequent digital block and compared at a certain threshold level to generate the RFOK signal. Therefore, the focus is closed even on a mirror-surface area of a disc. This signal is also supplied to the microcomputer via the low-pass filer as the FOK signal, which is used for protection and gain switching of the RF amplifier.
1.1.5 Tracking error amplifier
The photo-detector outputs E and F are passed through the differential amplifier and the error amplifier to obtain (E - F), and then provided from the pin 138 as the TE signal. The low frequency component of the voltage TE is calculated as below.
C
TEO = (E - F) x 63k / 112k x 160k / 160k x 181k / 45.4k x 160k / 80k = (E - F) x 4.48 For the TE output, TE waveform of about 1.3 Vp-p with the REFO as the reference. The cutoff frequency in the subsequent is 21.1 kHz.
CD CORE UNIT
PE5611B
TE A/D
+ -
Pickup Unit
D
P5 P10
+ -
TEOFF setup
+ 80k
138
TEO
47p
160k 137
TE-
E
11
11
E
132 112k 63k
45.36k
161k
VREF
+ 45.36k
+ -
139
TE2
2.7k
+
P1 P6
-
160k
160k 20k 60k 10000p 140
1000p
F
9
9
F
131 112k 63k
TEC
-
VREF
+
Inside TEC
E
Fig.1.1.3 TE
F
6
CX-3240
1 2 3 4
|
|
|
> |
|