SONY • "PROTECT" ERROR •

[Pick]

SONY
MINI HI-FI COMPONENT SYSTEM
MHC-EC909iP



Unit normally displays "PROTECT", if speaker wires "cross" or touch one another.  After resolving this "wire issue", I simply unplug the unit & then plug it back in..  It then Powers on like normal!

However, this time is different.

I've unplugged all speaker wires from the back of the unit (and still "PROTECT" error is displaying, when I power on the unit).   <---  indicating that this error is not due to speaker wires, like normal.

I notice the unit "Clicks", a certain number of times, while powering on (before finally deciding to display "PROTECT").  Does anyone know where I can learn more about this?  Perhaps the number of times the unit "clicks", before Powering On, might indicate the problem / help to troubleshoot the error?  <--  If so, where might I find such information?

Any help is greatly appreciated.

Thanks! 

-Pick

Josh Pickeral
joshpickeral@verizon.net

[SL4P]

I’d guess the earlier short circuit has taken half or both the output transistors on one or both channels.
The protection logic is sensing DC where it shouldn’t be - and let’s you know, so you don’t fry the speaker coils.
Good luck.

[tooki]

Service manual came right up on Google: https://elektrotanya.com/sony_hcd-ec709ip_ec909ip_ver-1.0_sm.pdf/download.html

If you let Google suggest "Sony MHC-EC919iP Protect mode", you find lots and lots of discussions of the problem. 3 minutes of skimming suggest a few different fixes:
1. unplug, wait a bit, plug back in,
2. #1, but also spin the fan (by hand or with canned air), or
3. replace failed power amp IC

[radioFlash]

In addition to what has been suggested:
Check for physical damage--anything obvious like bulging caps or scorch marks?
Try tapping around with a plastic prod of some sort to see if behavior changes in case there's a bad solder joint or connection
Check the power supply voltages, particularly the standby voltage.

I had one Sony receiver that had random relay clicking and resetting due to bad solder joints (the Power supply was soldered to the PCB)
I had another Sony receiver clicking on startup and sometimes come up with Protect because the caps for the standby power supply were bad