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This was my initial method of installing a transistor in a
PSP. It is still a useful method but in this instance seems to be
un-necessary
Back to Lighted PSP Tutorial
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To wire our LED's so they will turn on with the
power LED turning on we used a PNP transistor. PN2907 is readily
available at Radio Shack. A transistor is basically a solid state
relay which is just what we needed. Since Sony didn't leave us
with any obvious sources of power to supply our LED's we are going
straight to the source, tapping it from the battery. This means if
we don't have some type of switch to toggle power on and off the lights
would stay on even when the PSP goes to sleep. (Thanks to
poopyhead852000 for re-doing the drawing with proper symbols etc) |
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To power the LED's we tapped direct to the
battery input, this was a bit harder than expected, it seems the solder
used to create the PSP doesn't want to combine with my normal 60/40
solder so it took a bit of fooling around to get everything to make a
proper connection. I suspect this is due to the new no lead
regulations in home electronics, I may be on the lookout for some new
solder. |
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I bread boarded out the circuit first so I could
see what worked and what didn't. It turned out that the status
LED's have power going to them all the time (even when the PSP is off)
when it is turned on they are provided with ground and the circuit is
completed and the corresponding green or orange LED turns on. We
get power from the battery, go from that into a 10ohm resistor, that
into all the positive legs of the 0603 LED's, all negative legs into the
collector of the transistor, the transistor middle leg to one of the
points in the photo below, the emitter to ground. I wired ground
to the battery but next time I will tap to ground somewhere closer and
run one less wire.
(note there are extra components on this breadboard just for storage,
two transistors and one resistor are not used in the actual circuit, the
two large solid core green wires supply ground and trigger for the
transistor, there is also a resistor on the output of the transistor all
positive legs are soldered to that) |
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I recommend soldering to the via's. Once cleaned
they soldered easily I suspect the resistors will have the funky solder
and be difficult to work with.
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Thanks Sony! Look at this huge compartment
they left us to work with. I think I will go with smt transistors
in the future but it was enough space to work with. |
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In this photo you can see some odd soldering, not
my best work but hey got er done. The Leg on the left in the photo
is connects to ground on the battery and buts against the steel holding
the LCD in place which is also ground so put those toward each other and
there's one less place to short out. Of course middle pin to one
of the points pictured above. |
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We then sandwich the resistor in electrical tape
to help resist shorts, lay er on top and test it out! |
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