The Sencore TR139 Transistor Tester manual provides detailed instructions for setting up and operating the device, which is designed to test transistors and diodes both in-circuit and out of circuit for parameters such as AC beta and leakage. It also includes troubleshooting guidance, explaining how to connect the tester to various components and ensuring accurate readings without damaging the transistors or circuit components.
Manual Overview
The Sencore TR139 is an in-circuit transistor tester designed for accurate testing of transistors and diodes. It measures AC beta and leakage, providing essential diagnostics for both high and low power transistors. The device features a large 6-inch meter for easy reading and is housed in a durable vinyl-clad steel case. For troubleshooting, the TR139 uses a series of switches and controls, including the NPN-PNP switch for polarity selection, and the Off-Beta-Leakage switch for selecting test modes. Calibration is achieved using the Beta Cal Control to adjust for internal impedance differences, ensuring precise beta readings. The tester connects to transistors via color-coded leads, with guidance provided for both in-circuit and out-of-circuit testing. In-circuit testing may require soldering additional wires for accessibility. The TR139 is designed to prevent damage from incorrect connections unless left in place for extended periods. The manual emphasizes the importance of beta and leakage measurements, with guidelines provided for interpreting these parameters based on transistor type and application.
Quick Issues Covered
- Diagnose AC beta and leakage issues in transistors.
- Calibrate beta readings using Beta Cal Control.
- Trace circuits with detailed schematics for accurate testing.
Overview
The Sencore TR139 is an in-circuit transistor tester designed for testing transistors and diodes in various electronic devices. It is a fully solid-state device, eliminating the need for tubes, and is suitable for use in servicing, laboratories, and production lines. The TR139 allows for accurate testing of transistors for AC beta and leakage both in-circuit and out of circuit. It also tests diodes and rectifiers for opens, shorts, and current ratios. The device features a large 6-inch meter for easy viewing and is housed in a modern vinyl-clad steel case. The manual provides detailed instructions on connecting the TR139 to transistors and using its various controls for effective testing.
Specifications
- Transistor Testing:
- Beta (hfe) measured at 200 cycles, Ic=2.0MA, Vce=20V
- Range Beta Accuracy: LO 2-100 45%, HI 10-500 5%
- Leakage (Icbo) measured at Vce=4V
- One range 0-100 microamps lower 1/2 of scale, 100-5000 microamps upper 1/2 of scale
- Diodes and Rectifier Testing:
- In-circuit – checked for shorts and opens, can be detected with loads of 20 ohms paralleling the device
- Out of circuit – checked for forward to reverse current ratio
- Electrical:
- 117VAC 60Hz 2.5 watts
- Physical:
- Dimensions – 9-1/2" high x 7-1/2" wide x 6" deep
- Weight – 7 pounds
Controls & Indicators
NPN-PNP Switch: Selects the proper polarity of DC voltage applied to the collector of the transistor under test and is used when checking the forward and reverse currents of a diode.
Off-Beta-Leakage Switch: Turns the power off and selects the HI or LO Beta range for the AC beta checks and the leakage range for LEAKAGE checks on both transistors and diodes.
Beta Test Switch: Used only when checking the beta of a transistor and is not used in the LEAKAGE position of the function switch.
Beta Cal Control: Adjusted for each transistor to compensate for the various internal impedance differences found in transistors and ensures an accurate beta reading.
Test Jacks: E or black jack connects to the emitter of the transistor. B or yellow jack connects to the base of the transistor. C or red jack connects to the collector of the transistor.
Installation / Setup
Refer to the PDF for details.
Operation
The TR139 In-Circuit Transistor Tester by Sencore is designed for testing transistors and diodes both in-circuit and out of circuit. It checks high and low power transistors for AC beta and leakage, and diodes and rectifiers for opens and shorts. The tester is equipped with a large 6-inch meter for easy viewing and is housed in a modern vinyl clad steel case.
To operate the TR139 for testing transistors, connect the red lead from the C jack to the collector, the yellow lead from the B jack to the base, and the black lead from the E jack to the emitter of the transistor. This setup is used for both in-circuit and out-of-circuit testing. If the leads are not accessible, connections can be made to other components connected to the transistor.
The TR139 features several controls: the NPN-PNP switch for selecting the proper polarity of DC voltage, the Off-Beta-Leakage switch for selecting the test mode, the Beta Test switch for checking beta, and the Beta Cal control for adjusting readings.
The instrument is versatile and useful for design, production, and servicing of transistorized equipment, providing essential measurements of AC beta and leakage. Beta is the current amplification factor, while leakage current is the current flowing between the base and collector when the emitter is open. Silicon transistors typically have low leakage currents, whereas germanium transistors can vary.
Troubleshooting & Error Codes
Refer to the PDF for details.
Safety & Warnings
Refer to the PDF for details.
Download MANUAL Service manual (PDF – 4.3 MB)
Sencore TR139 Transistor Tester Manual: Guide for operation, troubleshooting, and service procedures. PDF size: 4.3 MB.
- Brand: Sencore-tr139-transistortester-operation-service
- Model: MANUAL
- Type: Service manual
- File size: 4.3 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 TR139 Transistor Tester Overview
The Sencore TR139 Transistor Tester is a precision diagnostic tool designed to test and analyze various types of transistors and semiconductor devices. Ideal for technicians and electronics hobbyists, this device provides accurate readings that help identify transistor parameters such as gain (hFE), leakage, and junction integrity. Its compact design and straightforward operation make it an essential instrument for troubleshooting and servicing electronic circuits.
Main Features and Specifications
- Tests NPN and PNP bipolar junction transistors (BJTs)
- Measures transistor gain (hFE) with high accuracy
- Detects leakage current and junction defects
- Supports testing of diodes and other semiconductor devices
- Easy-to-read analog meter display
- Compact and portable design for field and bench use
- Durable construction with reliable internal circuitry
Basic Usage and Operation Tips
To use the Sencore TR139 Transistor Tester, first ensure the device is properly powered and calibrated. Insert the transistor into the designated test socket, matching the leads to the correct terminals (emitter, base, collector). Observe the analog meter reading to determine the transistor’s gain and check for any leakage indications. For diodes, connect the leads accordingly and verify forward and reverse bias readings. Always handle components gently to avoid damaging delicate leads or sockets.
Troubleshooting and Maintenance Notes
If the tester fails to provide accurate readings, check the battery condition and replace if necessary. Clean the test sockets regularly to prevent oxidation and ensure good contact. In case of erratic meter movement, verify that the internal fuses and wiring are intact. Avoid exposing the device to excessive moisture or dust, which can degrade performance. Periodic calibration against known reference components is recommended to maintain measurement accuracy.
Safety Reminder
Always disconnect the transistor tester from any circuit before testing components to prevent electrical shock or damage. Use the device only within its specified voltage and current limits. Handle all electronic components with care to avoid injury or component damage. Follow standard safety protocols when working with electronic equipment.