414 Mk II Portastudio Troubleshooting

Discussion in 'TASCAM DIY Repairs and Mods' started by Paul Dixon, Jan 29, 2020.

  1. Paul Dixon

    Paul Dixon New Member

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    Gear:
    414 Portastudio Mk II
    Trying to repair a 414.

    The faults seem to be only with Channel 1.

    Anything I plug into the mic/line in socket for Channel 1 comes through at a very low level, even with the trim all the way up. It is too low to activate any of the LEDs in the meter, and to make a passable recording.

    If I use an adapter cable and plug the same instrument into the balanced mic aux input on the back, the meter will read a level (but quite low compared to the other channels), and I can record a passable track on Channel 1, but it is at a much lower level than the other channels.

    When I go to mix down my finished recordings, there is no output at all from Chanel 1 when I click on the monitor out switch and use the monitor out RCA outputs. If I click on tape cue, I then get Channel 1 from the monitor out RCA outputs.

    I've had a look at the internal PCB and see no obvious signs of component damage.

    Any suggestions as to where I should start looking, or what components I should start replacing?
  2. SkywaveTDR

    SkywaveTDR Active Member

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    From:
    Chicago area
    Gear:
    Teac, Tascam, Sony
    It can be a dirty switch or that someone plugged in something way over the allowable voltage that the input is suppose to have- I have had the first op amp chips blown out from some guys plugging in guitar amps into these things. It kind of sounds like there is a blown out circuit in the mixer section.
  3. Paul Dixon

    Paul Dixon New Member

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    Gear:
    414 Portastudio Mk II
    Thanks very much. The guy I bought it off was both a guitar player and an idiot!! Your analysis makes sense.
  4. Paul Dixon

    Paul Dixon New Member

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    414 Portastudio Mk II
    Next question - does anyone know where I can source a schematic or service manual for this unit?
  5. SkywaveTDR

    SkywaveTDR Active Member

    Joined:
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    From:
    Chicago area
    Gear:
    Teac, Tascam, Sony
    I usually check with Stereomanuals.com for duplications but if he does not have it then I look on E bay for a person selling one that is the original. I don't want any Pdf files off E bay and anyone else as these are usually scanned files done by low high school level people- or idiots if you prefer. I looked and it looks like Rick does not have many 400 series Tascam Porta Studios decks.
    http://www.stereomanuals.com/man/rep/tascam/index.htm