Once again this video is
coming from the top of
a flight case in the middle
of a crew room of a show
so you'll hear sort of noise in the background
and fans and stuff like that
So this is an infrared thermometer
and it's faulty
It's supposed to be that when you pull
the trigger it fires an infrared beam out
sorry it fires a red laser beam out
to create a dot
and the point that you shine the
dot at, it gives you an indication of the
temperature on the LCD display.
But this one is completely dead
and the battery is fine
so I'm wondering if a connection's
come off
so let's pop this open
and I can see there's two pillars here to
start off with, with screws in them
but I'm not sure if they've concealed
screws under the labels
I'll find out when I ease this open
I don't know if maybe these are just
gonna pull off
that does pull off
revealing the display and the buttons
does the front come off?
yes it does
ooh there's the whole module inside
so there's a laser module that's
been sort of pressed into
this sort of plastic tube
and it's been, uh, had some heatshrink
put around to hold it in place
here's the
the infrared detecting lens assembly
plus what I guess is probably going
to be a little thermistor
just to measure
it is, it's a little bead thermistor
just to measure the temperature
of the actual sensor area itself
to get an ambient temperature
and that will offset to the
the temperature of the device its
looking at
so let's pop this out
oops springs that's a (something) one
springy things
so, uh
the leads
let's put the battery on and
measure and see if power is
getting onto the board in the first place
I'll measure that from the back here
so let's bring the meter in
I'll use my traveling meter
ooh it's picking up a lovely picture of the
the magic arm that I'm using to hold this
camera in position
so let's uh
put onto these connections
so power is getting onto the PCB
so if there's nothing really obvious
in terms of broken connections or
anything like that
I would say that there may actually be a problem
with the chip under here, may have died
and that's a bit of a terminal situation
because it's one of those chip on board
type things like that
I'm guessing there's really not much you can do
when these chips fail here
because they're just not replaceable
and even if it was replaceable it would maybe
cost more to get replacement chips
in some instances than it would to just
replace the whole unit
in that case let's treat this as a
dead unit and take it to bits
the laser module looks very common
it's a little brass module
and let's take this little bead thermistor off
with its sticky pad that holds it on
and take a look at the sensor
which should be quite interesting
oh
so it's got about
four pins
two which may be screened
I wonder if they're mainly for support
that feels quite heavy, this assembly
it feels like it may actually be
metal?
or very dense plastic
and it's looking into one of those
polythene lenses to actually shape
the beam a bit to give it the sort of area
it's going to cover
there are just two connections
going into the back of this though
so I'm guessing it's just going to be
a pyroelectric device which is putting out a small
voltage differential
I'm not sure if that will have
some sort of amplifier in it that
I guess it could like a lot of these devices
like the passive infrared detector units
use the little high gain transistor inside to
initially boost the signal up
I'm guessing that might be the same here
so it's putting out basically sort of acting as an analog sort of voltage
so the chip can actually just basically determine
the temperature from
ultimately I guessing if it's the transistor it'll be sort of a
resistance it sees
but there's not a lot in them, they're mass produced
that's what you'd expect
what looks like a little voltage regulator down here
not sure what that chip will be
and then just the usual blob and the LCD
on the back which will be doing most of the stuff
so it's interesting, it's interesting how
it's put together it is very mass produced
and kind of simpleish inside but that's just
what happens with mass produced products