🚀 go-pugleaf

I appreciate that you've checked the motors, but very often if you carefully
check the spindle motor with an ohmmeter while SLOWLY rotating it you will
find it's shorted through 1/2 it's rotation. You could also run the motor
via a 10 ohm resistor and look at the voltage across the resistor with a
'scope as the motor turns. The waveform across the resistor should be nearly
constant. If the voltage across the resistor can be seen to spike largely at
the 1/2 turn intervals, then the brushes are shorting (or opening, though
this isn't happening in your case).
You could also disconnect the motors and see if the overheating stops.

Bottom line, something's drawing too much current. The IC itself could be
bad, though I kind of doubt it. If there's 2 of them in there you could swap
them. If it's not the motor(s) then something else should be getting hot,
though as I say the STA chips are used for motor drive.

Mark Z.



"Jim Lazzaro" <jim_lazzaro@hotmail.com> wrote in message
news:f666726f.0204101747.d02507d@posting.google.com...
> Thanks for your info; I have checked the motors but are not shorted
> and I ahve checked various caps but nothing found.
> The fact that the voltage at input pins is only 11.4 compared to the
> other similar IC concerns me.
> To narrow my search, what component failure could cause this lower
> voltage?
> Jim
>
> "Mark D. Zacharias" <mzacharias@kscable.com> wrote in message
news:<l3%r8.31022$1a.9486409@twister.kc.rr.com>...
> > The STA chip is a transistor array. If it's getting hot you have a
shorted
> > motor. Usually the spindle motor.
> >
> > Mark Z.
> >
> >
> > "Jim Lazzaro" <jim_lazzaro@hotmail.com> wrote in message
> > news:f666726f.0204070723.2f81b1d0@posting.google.com...
> > > I have this cd player that attempts to read disk but then stops and
> > > does not play the track.
> > > I have found an IC (sta451c) that gets very hot to touch within a few
> > > minutes of turning the unit on. Its input voltage is 11.4 volts.
> > > I have also noticed that on this board there is another similar IC but
> > > this one has input voltage of 18.5 volts.
> > > Shouldn,t both ICs (being both sta451c) be supplied with equal input
> > > voltages?
> > > I wonder if I should investigate what causes a low supply voltage of
> > > only 11.4 volts to the IC that gets very hot.
> > > Thanks to anyone who can assists.
> > > Jim from downunder Melbourne AUS.