Contract engineer Stephanie Donnell has dealt with more than her fair share of power supply problems. One common issue is dirt. Clogged power supply modules will affect performance. In one former job, she worked as a sustaining engineer for a company that produced huge color inkjet printers. One of her tasks was to extend the lives of the main power supplies used in these minibus-size systems. The supplies were rated at 4 kW and operated on three-phase, 208 VAC. Seasoned engineers will know that supplies at this power level turn into “dust magnets,” as do the supplies in high-power transmitters. The “mainframe” of each supply was about the size of a shoe box. A mainframe would be loaded with various modules set for various DC output voltages, depending on the model of printer. The modules could be removed easily from the mainframes, which allowed her to configure the power supplies. It didn’t take her long to realize that a big reason many of the power supply modules were failing was a heavy buildup of dust and “fuzz.” This led to the modules overheating, accelerating their failure rate greatly. Unfortunately, this had not been addressed as part of routine maintenance. Keep switching power supply chips running cool. Dust-choked vent intakes also can result in equipment faults. But the vents might not be where you expect them to be. Early in her career, Stephanie was alerted to a silence condition at one of the transmitter sites she maintained. The equipment was in an older wood-frame building with no air conditioning. Cooling was by way of drawing in the outside air and venting the hot air back out with a fan. When she arrived at the site, the fan was operating, as was the transmitter, but there was no program audio being fed into it. She traced the “failure” to the Aphex processor. She touched its case and felt blazing heat. Had its power supply failed? Or perhaps its cooling fan? At this point, she wasn’t sure that the processor even had a fan because there wasn’t a vent on the rear of the case. Then she found it, along the SIDE of the case. The intake was completely covered with fuzz. She cleared the opening and allowed the fan to cool the inside of the processor. It returned to life, and program audio reappeared on the transmitter. When… [TheTopNews] Read More.
2 days ago
