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 25V
p8 0V