Dr-40 External mic problem

Discussion in 'Handheld and Field Recorders' started by B Barboza, Jan 13, 2019.

  1. B Barboza

    B Barboza New Member

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    Gear:
    DR-40 and DR-07 MKii
    Hi! I have a DR-40 turning off when i try to use an external mic. The device simply turns off.

    In the "Rec Mode" menu, when I select the "Dual mode", "Overdub", "4 channels" or change the Source to "Ext Mic" (Mono or Stereo) the DR40 turns off (with a clicking sound too).

    The device is recording normally with the internal mics, but with this problem i can't use any external mic! It doesn't matter if the "Ext in" key is in the Line, Mic or Mic+Phantom position. It doesn't matter if a mic is plugged in or not.

    After a hard search, the only thing I found was a video on youtube showing exactly the same problem. I will share to make easy to understand what are happening!



    I will be very glad for any solutions or any kind of suggestion!

    Thank you!
  2. Art Anderson

    Art Anderson New Member

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    DR-40
    I think you have a problem requiring service. The only do it yourself thing I would try is changing the version of firmware, either up a version or even backwards from what you have now.

    My unit has had some unexpected shutdowns I can't explain, but none were when I am changing the menu setups and none I can confidently repeat like the shut off you have.

    I have had fewer of my shut offs happen since I keep the unit powered by USB power instead of batteries, but that's not really a good answer for a portable device. Good luck.
    B Barboza likes this.
  3. jmhmzz

    jmhmzz New Member

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    DR-40
    Hi. I am experiencing the same issue at present.

    I have been using my DR-40 during the past 4 years to record in any of the available modes, with original factory firmware and without any trouble.

    Currently, any attempt to set REC MODE in order to involve EXT MIC / LINE IN ends up with an abrupt power off of the recorder. No difference of using USB power source or batteries. I have also tried the suggestion to update firmware to the most recent version but the problem persists.

    After some investigation, my best guess is that selecting an external source drives the device to an abnormal consumption, or may be the built in power supply circuitry is now failing. In any case, I am afraid that from now on it will be able to deliver just as an standard stereo recorder, not any more as a full featured one.

    Honestly, I was not expecting requiring servicing that early from a TASCAM device.
    Last edited: Jul 6, 2022
  4. Art Anderson

    Art Anderson New Member

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    DR-40
    You would have to let us know what those external sources are that you are plugging in and what the input settings are on the DR-40 for each of those to even begin.
  5. jmhmzz

    jmhmzz New Member

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    DR-40
    Hi Art,

    Thank you for your interest and for asking me for clarification. I realize that in my previous message I did not made it clear that this behavior is observed without any EXT MIC / LINE IN connected to the unit. Just trying to select any other option different from MONO or STEREO with internal mics through the REC MODE button is equivalent to remove the power supply. The device simply goes off.

    In case it was of interest to you or any other forum member, here follows an update to the case...

    As I have some experience in electronics, I have finally decided to give the unit a second try. This was motivated by the fact that after gathering some technical info of the unit over the web, and opening it to have a deeper look inside, I noticed that it was an excellent engineering work deserving some more effort. More over, I suspect it might have been damaged due to an electrostatic discharge or even a misuse at any point (unfortunately I have not been the only one having access to it all the time).

    In order to go ahead with it, I have contacted TEAC America Parts department by e-mail asking them for the service manual, and they were kind to promptly answer that unfortunately they do not ship out of the US. So I have to ask for it to any one of the European service parts dealers... In the mean time, I have been doing some further investigation following some signal and power supply tracks of the circuit boards (a little hard task without schematics even with a microscope on multilayer PCBs) and centered my attention on one of the two CS42L52 codecs of the analog section. Fortunately the technical information for this chip is available from the manufacturer web site, and its being very useful to understand how the recorder works.

    I will try to write a new update with additional details in case of further findings.

    José M. Hernández
    Spain
  6. jmhmzz

    jmhmzz New Member

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    DR-40
    Hi again,

    The unit was finally recovered thank to TASCAM Germany (Triplex Service GmbH). The recorder is currently performing properly on all the selectable modes.

    For the case it was useful to anyone interested in this or similar issues, here follows an update that may help to understand the reason behind the described failure.

    Failure was due to an integrated circuit responsible for providing +/- 5v to the analog multiplexers when the MIC/LINE input is selected. To optimize consumption, this IC gets only powered by the microcontroller when it is required depending on input selection. An excessive consumption at this point is what was making the recorder to switch off.

    Perhaps it would worth noting that replacement of the faulty chip is a hard task to be done without specialized tools. It is a really tiny component and there is a serious risk of causing a permanent damage to the recorder in the attempt.

    Cheers,

    José M. Hernández
    Spain
    Art Anderson likes this.
  7. Art Anderson

    Art Anderson New Member

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    Thanks for coming back with an explanation José. A lot of people come back only to say "Fixed it." with no further comments that would help anyone else. I find that more rude than not coming back at all, because that is self centered.

    I hope you get many more years of use from your DR-40.
  8. phrtza

    phrtza New Member

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    DR-40
    My Tascam DR-40 external input died today. Exact same issue as in this video: https://www.youtube.com/shorts/OZreY6u53lk

    Seems like a widespread issue and each and every one of these devices will eventually die. The same might go for the new DR-40X, so I am reluctant to buy that one.

    jmhmmz, or anyone else, do you know which exact chip to replace and where? I can solder (if it is not BGA) and maybe the chip is available from mouser or farnell or even aliexpress.

    Thanks.