The Sencore TF26 Touch Tone Cricket service manual provides detailed instructions on setting up, operating, and troubleshooting the device, which tests transistors and FETs for gain and leakage without needing technical knowledge of the components. It includes safety reminders, descriptions of controls and connections, operational procedures for gain and leakage tests, and troubleshooting charts to assist technicians in diagnosing and resolving issues with the device.
Manual Overview
The Sencore TF26 Touch Tone Cricket service manual provides detailed instructions for operating and servicing the TF26 transistor and FET tester. The manual emphasizes safety precautions, such as discharging capacitors and using insulated floors to prevent shocks. The TF26 simplifies testing by using a computer logic circuit to determine transistor or FET functionality without needing to know basing or polarity. For gain tests, technicians connect the device and press six pushbuttons; a “chirp” indicates a good device. If no chirp occurs, the device may be faulty, though retesting out of circuit is advised. Leakage tests require the device to be out of circuit, using the same buttons that indicated a good gain test. Acceptable leakage varies by device type, with FETs and small silicon transistors showing zero leakage, while germanium power transistors may show up to 3,000uA. Calibration instructions include static and electrical meter zeroing, signal balance, and leakage calibration. The manual also provides troubleshooting charts and board-level guidance for disassembly and component replacement.
Quick Issues Covered
- Diagnose transistor/FET issues with gain and leakage tests.
- Calibrate static and electrical meter zero for accurate readings.
- Use schematics for circuit tracing and logic circuit understanding.
Overview
The TF26 Touch Tone Cricket is a transistor and FET tester that simplifies the process of determining whether these components are good or bad. It does not require knowledge of the basing diagram, polarity, or the specific type of device being tested. The tester uses an exclusive computer logic circuit to determine if a transistor or FET will invert a square wave input, providing an audio “chirp” and visual indication for successful tests. It can test any transistor or FET in or out of circuit and automatically checks for leakage. The manual covers safety reminders, descriptions, features, specifications, controls, connections, operation procedures, circuit descriptions, disassembly instructions, calibration instructions, trouble charts, and service and warranty information.
Specifications
- TYPE DEVICES TESTED: Diodes, transistors, and single gate FET’s.
- TEST VOLTAGES:
- GAIN TEST: VcE – Plus or minus 5V
- VBE – 3 volts peak to peak, centered on zero reference.
- LEAKAGE TEST: Vcp – 5 volts
- TEST CURRENTS FOR GAIN TEST: Ic -10mA max. 2 – 3mA average continuous Ip – 7mA max. 3mA average continuous.
- SEMICONDUCTOR COMPLIMENT: 7 – 1N4148; 2 – 2N5172; 1 – 2N4248; 1 – 10 volt zener; 1 – LM3900 Quad op-amp; 1 – SN7400 Quad NAND gate.
- METER LIGHT: 1-No. 47 Pilot Lamp
- SIZE: Height: 10” (25.4cm) Weight: 4 Ibs. (1.8Kg) Width: 5 1/2” (13.8cm) Depth: 3 1/2” (8.9cm)
Controls & Indicators
The front-panel controls/indicators include a polarity switch, a function switch, and six pushbutton switches. The polarity switch selects the test voltage polarity for the device under test, while the function switch allows selection between gain and leakage tests. The six pushbutton switches apply test voltage to the device elements.
Installation / Setup
Refer to the PDF for details.
Operation
The TF26 Touch Tone Cricket is used to test transistors and FETs, both in and out of circuit, without needing technical knowledge of the device’s basing or polarity. The device uses a computer logic circuit to determine if a transistor or FET will invert a square wave input. The gain test can be performed by connecting the test leads to the device and pressing each of the six test buttons in turn. If the device is good, the Cricket will chirp and indicate in the good area of the meter. If it doesn’t chirp, the device is probably bad. The leakage test requires the transistor to be removed from the circuit, and the test is performed by pressing the two buttons that gave a good gain test. The leakage should measure zero for FETs and small silicon transistors, while high power silicon and small germanium transistors may indicate up to 100uA leakage, and germanium power transistors may indicate up to 3,000uA and still be acceptable.
Troubleshooting & Error Codes
Refer to the PDF for details.
Safety & Warnings
When testing electronic equipment, there is always a danger present. Unexpected high voltages can be present at unusual locations in defective equipment. The technician should become familiar with the device that he is working on and observe the following precautions:
1. When making test lead connections to high voltage points, remove the power. If this cannot be done, be sure to avoid contact with other equipment or metal objects. Place one hand in your pocket as a safety precaution and stand on an insulated floor to reduce the possibility of shock.
2. Discharge filter capacitors before connecting test leads to them. Capacitors can store a charge that could be dangerous to the technician.
3. Be sure your equipment is in good order. Broken or frayed test leads can be extremely dangerous and can expose the technician to dangerous potentials.
4. Remove the test leads immediately after the test has been completed to reduce the possibility of shock.
5. Do not work alone when working on hazardous circuits. Always have another person close by in case of accident. Remember, even a minor shock can be the cause of a more serious accident, such as falling against the equipment, or coming in contact with high voltages.
Download MANUAL Service manual (PDF – 5.2 MB)
Sencore TF26 Touch Tone Cricket Manual: Troubleshoot and calibrate efficiently. PDF size: 5.2 MB.
- Brand: Sencore-tf26-touch-tone-cricket-operation-service
- Model: MANUAL
- Type: Service manual
- File size: 5.2 MB
Overview
Brief overview of the product.
Specifications
- Key spec 1
- Key spec 2
Controls & Indicators
Control panel/button layout.
Installation / Setup
- Step 1…
- Step 2…
Operation
Basic usage, modes, cycles.
Troubleshooting & Error Codes
| Issue / Code | Fix |
|---|---|
| Example | How to fix… |
Safety & Warnings
- Important warning…
Downloads
Download MANUAL service manual (PDF)
Sencore TF26 Touch Tone Cricket Operation Overview
The Sencore TF26 Touch Tone Cricket is a specialized test instrument designed to generate and analyze touch tone signals used in telecommunication systems. It is primarily utilized by technicians and service personnel to simulate and verify DTMF (Dual-Tone Multi-Frequency) signaling for telephone line testing and troubleshooting. This device ensures accurate tone generation and detection, facilitating efficient maintenance and repair of telephony equipment.
Main Features and Specifications
- Generates all standard DTMF touch tone signals
- High-precision frequency accuracy for reliable testing
- Compact, portable design for field and bench use
- Easy-to-read display indicating tone output and status
- Compatible with a wide range of telecommunication equipment
- Durable construction for long-term service use
- Simple interface with push-button tone selection
Basic Usage and Operation Tips
To operate the TF26 Touch Tone Cricket, connect the device to the telephone line or test circuit as specified in the manual. Use the push-button keypad to select the desired tone sequence. Verify tone output using a compatible receiver or monitoring device. For best results, ensure the device is powered correctly and cables are securely connected. Regularly calibrate the unit according to the service schedule to maintain accuracy.
Troubleshooting and Maintenance
If the device fails to generate tones or produces distorted signals, check all cable connections and power supply first. Replace batteries if applicable. Clean the keypad and connectors periodically to prevent dirt buildup. If problems persist, consult the detailed troubleshooting section in the manual for step-by-step diagnostics. Routine maintenance includes inspection of internal components and recalibration by qualified personnel to ensure optimal performance.
Safety Reminder
Always disconnect the TF26 Touch Tone Cricket from the telephone line before opening the case or performing maintenance. Avoid exposure to moisture and extreme temperatures. Use the device only as intended and follow all safety instructions in the manual to prevent electrical shock or damage to equipment.