Burnt and burst SMPS supervisor on this otherwise no-name and little chance Chinese thing. As laser and motor/s in the DVD deck and heatsink bonded to a video chip a reasonable power draw. But the SMPS IC , in a conventional 8 pin DIP package also contains the Tx driver transistor. So air gap under the IC and reverse side of pcb enlarged pad of pcb-copper as some sort of vain attempt at heatsink. Thermal connection to this is via just pins 4 and 5 combined in normal soldering , connected to the Tx. There is a hole through the pcb as though for some sort of clip to go perhaps top and bottom of the IC and bolted through to this under pad but no sign of anything having been fitted there, no deformation of the tinning over the pad around the hole. Turning over the unit and shaking over paper meant the blasted away top part , mainly, of the IC emerged but no clip at all. Is it possible to have combined supervisor and driver transistor in an
8pin DIP package with no heatsink tab provision? or are there combined SMPS TX with internal driver transistor buried in the base? Also ps supply provision marked on pcb ac 85V - 250V IC logi i in a reversed D marked in 3 lines ICE 2?26 maybe more numbers, ? maybe a 4 logo then 0 and more XK4.. probably more numbers probable pinning p1 0.1uF to 0V p2 to optocoupler p3 over current sense p4-p5 to Tx low side p6 n/c p7 supply- posted
10 years ago