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High pitch sound through speaker when turned off.

DaveDave Member
edited November 2018 in FLEX-6000 Signature Series
Received a 6600M on Friday and have noticed the following on shut down and power up. It has been updated to 2.2.8. Please let me know if this is normal. 

Start up.
Turn on 13.8 power supply 
All the front panel display lights turn on for 1 sec
Push the power up button, powers up normal

Push power button momentarily to turn off 
Radio powers down
Screen turns black followed by loud pop
Radio speaker is still on with hash noise and constant high pitch sound
F2 button still illuminated - this is intermittent
I can see through the side vent that a green light is still active. 





  • edited November 2018
    Yes, my 6600M does the same 

    F1 says on ( If already ON before Power Shutdown ) if I power down 
    Pop is normal, Audio Amp is last to Power Off & 1st to Power ON with POP Noise

    Have not heard Hash Noise and Constant high pitch sound 
    but my hearing is not that good for High Frequencies

    Check your Audio Menu to make sure your Slice Audio 
    is not too high ( Mine is 50% on slider )

    Also check your EQ Rx Audio Settings as well 

    73 Mike
  • Robert LonnRobert Lonn Member ✭✭
    edited May 2018
    Yes my F1 and other F stay lit green on power down. Slight pop in audio at power down and then I turn off my power supply and then of course the green lights turn off. I have not powered off but left power supply on and listened to the. Audio. I will try that on Sunday. My 6600M is just a few weeks old. I want to think this is a software issue on how the radio powers down as the F1 green light staying on is Intermittent as sometimes the green lights goes out!! Now that more folks are reporting this Flex can look more into this! Neal is aware of this at Flex!! Robert
  • DaveDave Member
    edited May 2018
    Hi Mike, the menu settings are all factory as I have just received it and making my way through the manual. Slice and master audio is at 50%. Pops and other electrical anomalies always grub your attention. If this is normal then than all good, what an amazing radio. Its like starting the hobby again. 
  • WayneWayne Member ✭✭
    edited May 2018
    Sounds like you may need to do a cold boot by removing the power cord after shutting down wait 15 seconds reattach power cord and turn back on .... or if that does not help then a factory reset by holding the power button until it turns white. The cold boot may not have been performed after the latest load before your radio shipped. I fought with mine about 4 hours after the update before I got it right,. If neither of these fix your vfo detent menu issues either then the help desk is the way to go.
  • WayneWayne Member ✭✭
    edited May 2018
    Just another note when i updated to v2.2.8 when i turned off the flex before i turned my power supply off the flex radio screen that said flex radio stayed displayed both on the flex 6400m panel and the hdmi monitor even though otherwise the rig had shutdown. A cold boot fixed that and its been perfect since.
  • Robert LonnRobert Lonn Member ✭✭
    edited May 2018
    For a while under the older software this F1 issue stopped! But after the 2.3 load it came back! I will try a full factory reboot and report back!
  • Robert LonnRobert Lonn Member ✭✭
    edited May 2018
    Did a full reset, no change, so this may in fact be a hardware issue as Flex has identified this.. 

  • edited May 2018
    With an external Hi-Fi Pre-amp, can detect a slight high pitch Tone, will pull out my Oscilloscope to look at it to see if real or self induced problem due to ground loops, but have no high Pitch Tone on the Flex6600M Speaker, only with a headset plugged in feeding external Audio Stereo Hi-Fi Amplifier with wide AF frequency response I slightly hear it

    Will look at it with my oscilloscope, but can turn audio up on 6600M and turn external pre-amp down to effectively roll it off

    Can not hear it in my RadioSports RS60CF HeadSet, but there again, these do not
    respond super high in frequency to reduce distortion effects

    May be easy to roll off with a Simple RC network if really an issue for you, but my Flex6600M 
    with Speaker and RadioSports RS60CF Headsets hear No High Pitch Tone

    Make sure your Monitor Button is off to see if that has an effect

    73 Mike

    P.S. No high Pitch Tone detected when the Flex6600M the is power off and 12V supply stays connected 

    Well, I Connected my Hitachi Oscilloscope today and to Audio Output on Flex6600M and found NO High Pitch Tone when to Headphone Jack when On, super Clean 

    Also Power Off,  No Tones seen on my Hitachi Scope as well

    --> Suggest you E-mail Support at Flex for Help

    Maybe a ground loop or something, call them if you can not resolve it on your own

    My Flex6600M is the latest run after April 12th shipments

    As I said no high Pitch Tone heard unless I get creative with a Hi-Gain External Pre-Amp,
    so output impedance may be issue or ground Loop.

    Super Clean on my Oscilloscope, nothing riding on Audio Waveform, maybe your having 
    something coming in from a switching supply into your Flex6600M 

    Try a DC battery to eliminate DC supply switcher issue getting into your Audio 

    73 Mike
  • DaveDave Member
    edited November 2018

    Thanks for your reply and testing.

    I received the 6600M last Friday 18.05.2018, serial No 1318 9765 6601 1892. I tried everything suggested here but still have a very high pitch noise and white noise coming from the front speaker when the speaker is turned off and on from the menu after shut down. Its like its not isolated from an active power source inside the radio. Its not very loud but its enough to turn off the main supply when I'm working.  

    I will report to the helpdesk and see what happens.

    Thanks for your help 

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