Schematy są ale można wysilić się i zrobić kolorowy skan i o większej rozdzielczości. Wtedy schematy płytek będą czytelniejsze. Całość super jako wartość merytoryczna. Wszystkie dane potrzebne do podłączenia różnego rodzajów urządzeń takich gramofon, CD itd.
jedyne do czego mogę mieć zastrzeżenie to jakość zdjęć zawartych w przesłanej instrukcji serwisowej ponieważ są fatalnej jakości, praktycznie nieczytelne. tak poza tym jestem zadowolony to jest to czego szukałem.
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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.
