Kenwood TK-940 service manual LCD Assembly, Cpu, Power switch circuit, Tone generator

Models: TK-940

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CIRCUIT DESCRIPTION

1)'7.LCD Assembly

The LCD assembiy consists of CPU, LCD, power switch circuit, and tone generator.

7-1. CPU

The CPU (IC2) carrres out the f o l o w l n g main operatlons:

It sends onloff data serially to the control unit from the AF volume control, LIPIDOWN key, system UP/ DOWN key, group UPIDOWN key, SCAlV key, and AUX key. It receives serial data from the control unit and displays it on the LCD.

The LCD can indicate alphanumeric characters (13 segments, 8 d~gits),TX, BUSY, CALL, SCAN, Talk- around, Option, AUX, TEL, and Delete.

7-2.Power switch circuit

Each time the power key IS pressed, a pulse IS sent t o the TX-RX unlt to turn the transceiver on or off.

7-3. Tone generator

The beeps and alert tones are generated by combining square wave signals of about 700Hz, 900Hz, and 1500Hz generated by the CPU These signals are output from pins 46, 47, and 48 of the CPU (IC2).The signals are rectified by a CR network and fed to the TX-RX unit LCD assembly and the de-emphasis circuit of IC9 (212).

Fig. 10 Tone generator circuit

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Kenwood TK-940 service manual LCD Assembly, Cpu, Power switch circuit, Tone generator

TK-940 specifications

The Kenwood TK-940 is a highly regarded mobile two-way radio that has earned a reputation for its ruggedness, reliability, and excellent communication capabilities. Designed for professionals in various sectors such as public safety, transportation, and construction, the TK-940 incorporates advanced technologies to meet the demanding needs of users in the field.

One of the standout features of the TK-940 is its robust design, which complies with military specifications for durability. Its construction allows it to withstand harsh environmental conditions, making it suitable for outdoor and challenging work environments. The radio is also equipped with a water-resistant casing, ensuring that it can function reliably even in wet conditions.

The TK-940 operates in the VHF frequency range, providing wide coverage and strong signal penetration. With a power output of up to 110 watts, users can achieve long-range communication, essential for coordinating activities over large areas. The radio supports both analog and digital modes, allowing seamless integration into various communication systems while maintaining high audio clarity.

Another significant feature of the TK-940 is its enhanced audio quality. The radio is equipped with Kenwood's advanced noise cancellation technology, which minimizes background noise and ensures clear voice communication even in noisy environments. The audio output is powerful and adjustable, catering to individual user preferences.

Moreover, the TK-940 supports a variety of signaling options, includingDTMF, MDC-1200, and 2-Tone/5-Tone signaling, facilitating efficient communication. These signaling features enhance interoperability with other communication devices and systems, allowing users to communicate seamlessly with teams or dispatch centers.

Kenwood has also incorporated user-friendly functionalities into the TK-940. It boasts an intuitive user interface with programmable buttons, enabling quick access to essential features. The large, backlit display provides clear visibility and is easy to read in various lighting conditions.

The TK-940 is designed with safety in mind, featuring emergency alerts and lone worker protection, ensuring users can communicate their status in critical situations. Overall, the Kenwood TK-940 is a powerful and versatile mobile radio that combines durability, advanced technology, and user-friendly features, making it an ideal choice for professionals who require reliable communication in the field.