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There are currently no product reviews.
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Another excellent buy! A fully readable PDF archive. Good prints!!
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It is wonderful done!!! a great job in scanning the manual. Superior quality in all the electric scheme. Very understandable and net!!! Thank you!
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muy buen manual por lo completo de este algunos esquemas estan muy divididos lo que hace algo dificil el seguimiento.
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very good manual, with detail and clarity in esquematic diagrams and waveforms .
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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.
VGS-1
CIRCUIT DESCRIPTION
VGS-1 IC57 O 5V O I
IC2 94 pin R17 PA1 High : Normal Low : Shift
External device 5V
XTAL
IC2 MCU C10 Q1
EXTAL 66 X1
Pull-up resistor Pull-up resistor
67
C12
R18
R19 5V
I
Q2
Fig. 4 Fig. 3 External device, pull-up resistor
Beat shift circuit
â� AI Input Port
If input exceeds 100mVp-p, the input signal is clipped and distortion occurs. It is necessary to make setting so that no signals exceeding 100mVp-p are input. If the input level lowers, S/N decreases, so the maximum input not exceeding 100mVp-p must be used.
Amateur Transceiver Identification
The VGS-1 can be set as an amateur transceiver or a Land Mobile Radio transceiver in the factory. When it is used as a Land Mobile Radio transceiver, internal data in the VGS-1 is changed to suit the Land Mobile Radio transceiver, so it cannot be used as an amateur transceiver. The VGS-1 set as a Land Mobile Radio transceiver can be identified because the RV4 land on the PCB is at High level. The default is Low level.
â� AO Output Port
When recording is performed with a 100mVp-p input, the playback output becomes an approx. 2.8Vp-p level. If Prerecorded Voice is generated, the output is approx 2Vp-p.
C11
Beat Shift Circuit
To prevent VGS-1 clock oscillation for the MCU (IC2) from causing spurious reception to transceivers to which VGS-1 is connected, the clock oscillator (11.0592MHz) has a beat shift circuit with a transistor switch (Q1).
Accessory unit Foil side view
â� Beat Shift Circuit Off
Pin 94 of the MCU (IC2) goes Low level, Q2 turns off, and
RV4
RV3 RV2 RV1
Q1 turns on because a 5V bias is applied to its base. In this condition, C10 is shorted, so the oscillation frequency is unchanged.
Fig. 5 RV4
â� Beat Shift Circuit On
Pin 94 of the MCU goes High level, Q2 turns on, and Q1 turns off because its base is pulled down to GND. In this condition, C10 is connected in series to the crystal oscillator and the oscillation frequency increases by approx. 150ppm.
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