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Showing posts with the label motor-driver

Diagnosing and repairing an Audio-Technica AT-LP120-USB motor driver

As an audio enthusiast, Audio-Technica has long been one of my go-to brands for reliable gear. Back in 2016, I bought a brand-new Audio-Technica AT-LP120-USB direct-drive turntable. For nearly eight years, it performed flawlessly. Then came last June. While listening to a record, I noticed a subtle drop in pitch. I adjusted the pitch slider and tried tinkering with the speed controls, but the platter responded erratically. Within a few minutes, the rotation slowed down to a crawl and came to a complete stop. Power cycling the unit did nothing to jumpstart the motor, though all the status LEDs and indicators remained brightly lit. The main logic was alive, but the motor was completely unresponsive. I decided to open it up and see if I could save my turntable. Upon opening the chassis, I was surprised by the internal layout. Rather than a simple single-board design, the LP120 utilizes a complex modular dual-PCB setup: Control board: Handles user inputs, pitch control, speed switc...

Experimental motor driver for CG-4 German equatorial mounts

This is an experimental stepper motor driver for Celestron CG-4 German equatorial mounts . This unit is functionally equivalent to the Celestron dual-axis motor driver , and we developed it as a replacement unit for the original Celestron driver. The prototype circuit board of the motor controller unit. The core component of this motor driver is PIC16F88 8-bit MCU. This MCU is responsible for driving two motors and scanning the user inputs. As an original unit, this system also got a clock driver for the right ascension (RA) axis. This system uses two L293 motor drivers to drive the right ascension (RA) axis and declination (DEC) axis motors. This unit is designed to work with 6V bipolar stepper motors, which include in the telescope mount. The LM350 voltage regulator is used to maintain power to both stepper motors. Internal view of the prototype enclosure. This replacement motor drive provides all the functionalities of the original unit, which including manu...