Sony KP-53S35 Power Board “G”

After high voltage transformer was freed, I looked over the rest of this board. Aside from a big “G” next to the Sony logo, I didn’t find a designation marked on it. I’m calling this the power board just because this is where the AC power cable came into the television. Power enters through a connector in the lower-left corner of this picture. Accordingly, most of the larger components are clustered near that area, implying power handling duties. Many also had thin sheets of metal attached, either as heat sink or as shielding or possibly both.

Power Board top before

Near the center of the board is a curious connector – it just has a wire that loops back into itself. What could be the purpose of such a thing?

Power board curious connector

A big beefy 20W resistor with very low resistance of 0.82 ohms hint at a shunt, possibly for measuring current flow.

Power board 20W resistor

Enough looking, time to pull off the interesting looking parts, meaning pretty much every component which is not a resistor or a capacitor. I first started with the ICs on the board as I wanted them to practice free-form circuit building. I doubt my first attempts will look good, so I might as well start by creating circuits around chips that are likely nonfunctional due to excessive heat used to remove them. I had the heat gun hot enough and close enough so solder melted in under 30 seconds. That heat can’t be good for the chip!

Power board ICs removed

Emboldened by success removing these little chips in short order, attention turned to the big convergence control modules STK392-110.

STK392-110 convergence control amplifiers

Sadly their big heat sinks were very good at their job of dissipating heat so I couldn’t reach melting point of solder holding them to the board. I turned to removal via mechanical means, which is a fancy way of saying “ripping that sucker out of there.” I first removed the screws fastening the heat sink to the chip, then started pulling and rocking the heat sink. The metal leg on the right side held strongly to the circuit board and broke the board. The other side, however, is different.

Power board mechanical removal

The left side of the heat sink seemed to have popped free of its leg which is soldered to board. It looks like a little drilling will be enough to intentionally separate the heat sink from its attachment bracket, and that worked to ease removal of the second heat sink.

Power board drill to separate

Once the heat sinks were removed, the heat gun could free the STK392-110 modules. I reunited chip and heatsink for whatever their future holds.

Then the heat gun were pointed at the rest of power-handling components. Transformers, rectifiers, etc. They are relatively durable components and are likely to have survived the heat of their removal if I ever dare to use them for a future project.

Power board misc parts

And here’s the aftermath: a heat-charred and distorted circuit board still home to many uninteresting resistors and capacitors. It will be dropped off at electronic recycle.

Power board back after

 

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