Connect with us

SONY "PROTECT" MHC-EC909iP

Discussion in 'Audio' started by Pick, Sep 7, 2018.

Scroll to continue with content
  1. Pick

    Pick

    1
    0
    Sep 7, 2018
    SONY
    MINI HI-FI COMPONENT SYSTEM
    MHC-EC909iP


    [​IMG]

    Unit normally displays "PROTECT", if speaker wires "cross" or touch one another. After resolving this "wire issue", unplugging the unit & then plugging it back in then resolves the issue.

    However, this time is different.

    I've unplugged all speaker wires, from the back of the unit, and "PROTECT" error continues to display.

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

    Any help is greatly appreciated.

    Thanks! [​IMG]

    -Pick

    Josh Pickeral
    [mod edit: E-Mail removed, please reply within this thread or use private message (conversation) if necessary.]
     
    Last edited by a moderator: Sep 7, 2018
  2. 73's de Edd

    73's de Edd

    2,805
    1,176
    Aug 21, 2015
    Sir Josh Pickeral . . . . . . . . . . .

    The clickee- clickee noises that you are hearing are probably the effect of the overload condition causing relay
    RY701, in disengaging your amp power connection to the right and left channel speakers as well as RY801,
    disengaging connection to your B E E E G center speaker.
    One certainly does not want upwards of + or - 35 VDC at 500 + ma hitting the speaker voice coils.
    Touching the top cases of the two relays should let your sense of feel, confirm if they are the source of the clicks at power turn on / ons.

    The power amps are potted power modules IC604 for the R and L channels and IC606 for the center
    channel amp.

    A DC sampling is taken from the Audio output pins of the respective power amps (pins 4-5-6-7) and is fed to OVERLOAD detection circuitry, which then trips those relays to speaker disconnect in case of DC voltage coming from a defective POWER AMP module.
    Marked on parts designator for an IC604 is being STK433-870-E
    Marked on parts designator for an IC606 is being STK433-070-SE

    You initially gain chassis access to the two large potted modules and use metering of voltage in the DC mode and use meter ground to pin 10 and then see which of the pins 4-5-6-7 of either modules have in excess of probably a minimum of 1 VDC, which would then trip your overload detection circuitry.
    (Such as you are probably experiencing.)


    What else could you possibly need now ?

    RELEVANT TECHNO REFERENCING . . . . .

    upload_2018-9-7_9-22-9.png

    73's de Edd
    .....
     
    Richard9025 likes this.
  3. WHONOES

    WHONOES

    784
    174
    May 20, 2017
    Sounds like you have shorted an output once too often and wrecked an amplifier module. You probably need to get in there and do some measurements like the DC offset voltage of the amps.
     
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Similar Threads
There are no similar threads yet.
Loading...
Electronics Point Logo
Continue to site
Quote of the day

-