A capstan roller assembly is provided between the yarn supply and scroll type yarn feed attachments for a tufting machine in order to minimize the underfeeding of yarn to the pattern being tufted due to irregularities in the feeding of the yarn from the yarn supply. Techniques include using a diode laser assembly, a power source, a fiber optic cable, and a fenestrated tip. This device in its simplest form has the structure: electrode-active layer-buffer layer-active layer-electrode. Second contact pads are disposed on the first contact pads. The master controller manages the temperature within the electrolysis system to prevent freezing through circulation of water from the water management system. The LED substrates 30 are placed along the surfaces of the side walls, and the spacer members 34 are placed in the corners between the adjacent side walls 22b, 22c, 22d, and 22d.