This video presents an unboxing, initial review, and partial teardown of a recently acquired Tektronix AM503 current amplifier plugin and its companion TM500 series power module. The presenter details the remarkably low acquisition cost of $82, highlights the instrument's good external condition, and examines its internal construction, noting high-quality components like gold-on-gold PCB switches and gold-plated transistors. Initial functional tests confirm the system's ability to measure current and adjust gain, but also uncover cosmetic damage to controls (a broken knob and pull tab) and a significant functional issue with the DC offset potentiometer, described as "crunchy" and preventing proper adjustment. Despite these minor imperfections, the presenter concludes that the purchase represents an excellent value.
Tektronix AM503 Current Amplifier: Unboxing, Review & Teardown
0:00 Acquisition & Value: The presenter acquired a Tektronix AM503 current amplifier plugin and a TM500 series power module from eBay for an "amazing" price of $82.
0:45 Initial Functionality: Both the power module and the AM503 plugin are confirmed to be working, successfully outputting power and amplifying current.
1:10 External Condition & History: The instrument is in "very nice shape" with a good leather handle and features asset tags from "Dr. Design Incorporated" and calibration stickers from "Advanced Test Equipment Service" and "Simco" (dated 2004/2006).
3:20 Cosmetic and Minor Functional Issues: The main control knob is broken (missing 3/4 of its plastic, superglued for now) and a pull tab on the plugin is broken off. The DC offset adjustment knob feels "crunchy" and is not functioning correctly (4:12), preventing proper DC offset control (8:56).
5:05 Testing Setup & Probe Features: The probe is connected to a 50-ohm load and scope. The probe features an "unlock" mechanism (5:41) and a "degauss" button (6:11) for AC demagnetization.
6:21 Current Measurement Confirmation: The system successfully measures a 1 amp current passed through a wire loop, and the gain adjustment knob works as expected.
10:11 Plugin Removal Method: The presenter demonstrates a trick to remove the plugin despite a broken latch: unscrewing a specific screw (11:03) allows a rail to float, releasing the catch.
11:39 Internal Examination: A partial teardown of the AM503 plugin reveals its high-quality internal construction, including Tektronix's distinctive gold-on-gold PCB switches (12:22) and gold-plated transistors (13:33). The interior is described as "mint" (14:52).
14:21 Potentiometer Replacement Candidate: The faulty DC offset potentiometer is identified as a 10K pot, confirming it "doesn't feel right" and is an easy part to replace.
15:10 Conclusion on Purchase: The presenter considers it a highly advantageous purchase, emphasizing the excellent value for money.