Sir Novocaine . . . . .
From as few clues as it is giving you, likely that one of the audio output power sections . . .within the photos
ORANGE boxed area . . .probably failed and then knocked out your power supply.
There are two power supply sections, with the initial one of main interest being within the shades of
RED boxed in areas.
The high power one, being within the
BLUE boxed in area.
TESTING . . . . .
Initially have no
AC power to the unit and use an ohmmeter in its low ohms range to confirm that the F801 fuse
RED-YELLOW on schematic or
PINK box on photo is good..
Then track down the current limiter / fuse as the same color coded
RED-YELLOW designation of
IC808 . . . . it physically should be just like a TO-92 cased transistor, but with only
two opposing leads.
On the photo, the nearby
C17 electrolytic is being
RED starred and your item of interest should be in the
YELLOW star proximity.
To make a top of chassis, probe connections , one electrical connection is being to the cathodes of D809 or 810, the other electrical connection would be to the closest / nearby terminal of IC805, a three terminal 5 V regulator .
If both of those fusible parts are intact/ of /
LOW ohmmage and thereby, not being blown .
ADVANCE TO . . . . .
Powering up the unit and look over to
CN505 connector and measure its pin 4 double
RED-YELLOW BAR voltage and you must use the pin 3
BLACK bar connection point as the meter ground.
Repeat on the other single and triple
RED YELLOW BARS, using
their specific grounds.
If all
5 of those supply voltages are present we proceed . . . if not . . .we troubleshoot . . . . . as to why ?
If the unit is shutting down before actual required time to read their metering . . . . . have the unit off and have the probes
in place at turn on time .
AREA PHOTO MARK UP AND POWER SUPPLY SCHEMATIC . . . . . .
https://i.ibb.co/LPggZDL/PIONEER-SX-315-Pwr-Supply.png
73's de Edd . . . . .
STERILIZE . . . . . ( ster-i-līz )
Now, that's what you do to your FIRST baby's pacifier, by boiling it,
and eventually, to your LAST baby's pacifier, by just blowing on it.