JVC HRJ677MS
Service Manual

3.4

SYSCON CIRCUIT

Note: � When perform this adjustment, remove the Mechanism assembly. 3.4.1 Timer clock
Signal Mode Equipment (A) (B) (C) � No signal � EE � Frequency counter [HR-J271MS/J471MS] � IC3001 pin 29 � IC3001 pin 57 � C3015 + and � [HR-J677MS/J777MS] � IC3001 pin 61 � IC3001 pin 24 � C3026 + and �

Measuring point (D1) (D2) (D3) Measuring point (D1) Short point (D2) (D3) Adjustment part (F)

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[HR-J271MS/J471MS] � C3018 (TIMER CLOCK) [HR-J677MS/J777MS] � C3025 (TIMER CLOCK) � 1024.008 ± 0.001 Hz (976.5549 ± 0.0010 µsec)

Specified value

(G)

[HR-J271MS/J471MS] (1) Connect the frequency counter to the measuring point (D1). (2) Connect the short wire between the short point (D2) and GND. (3) Short the leads of capacitor (D3) once in order to reset the microprocessor of the SYSCON. (4) Adjust the Adjustment part (F) so that the output frequency becomes the specified value (G). [HR-J677MS/J777MS] (1) Connect the frequency counter to the measuring point (D1). (2) Connect the short wire between the short point (D2) and Vcc (5V). (3) Short the leads of capacitor (D3) once in order to reset the microprocessor of the SYSCON. (4) Disconnect the short wire between the short point (D2) and Vcc then connect it again. (5) Adjust the Adjustment part (F) so that the output frequency becomes the specified value (G).

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