My daughter has a Panasonic SL-SX270 "Walkman" type portable CD player
that failed. The symptom was an "F15" code in the display about a half
a minute after attempting to play a disc.

The "F15" code is not mentioned in the manual, and I did some
searching for tips on the net, but found nothing useful. I did find
references to others with the same problem, thought, and on other
Panasonic models as well, so this information might be useful even if
you do not have an SL-SX270.

I was able to repair the unit and thought I would document what I
learned here in case someone else is searching for this in the future.
Note that I am not a professional repair technician and do not have
access to official documentation, so some of the terms I use
components may be incorrect.

The "F15" code apparently indicates a failure of the laser assembly to
move to the "home" position at the start of the disc (all the way
towards the center).

There are two general ways that this code can appear: one is if the
carriage is unable to move, the other is if the player is unable to
sense that the carriage is in the home position. The former makes the
player unable to play, the latter causes "F15" to flash on the
display, but then the player works anyway.

In either case, the top candidate is the flexible circuit board
"cable" that connects the shock-mounted reader assembly to the main
circuit board. This cable has six conductors and carries both the home
sense switch signal and the for drive for the carriage positioning
motor, as well as the drive for the spindle motor.

It may be that the cable itself is broken or the connection to the
main circuit board may be the problem. In my case, one of the
conductors to the carriage motor was broken where the cable bent. I
bypassed it with some fine wire, which solved the problem.

In any case, troubleshooting can be directed to checking for
continuity of the motor, home position switch, and associated cable
and connector.

Also, a word of caution: the connector which this cable connects to is
somewhat fragile. If you think the problem is with the connection
between the connector and the cable, resist the urge to insert things
into the connector and bend the pins, as you will proably only make it
worse. Also resist the urge to insert test probes into the connector.

The connector can be "repaired" if it is unsoldered from the circuit
board and the pins pushed out from behind, reshaped, and then
reinserted. Best to avoid damage in the first place.