Porta 07 very low playback volume on channel 3 in remix mode

Discussion in 'TASCAM DIY Repairs and Mods' started by Dan Winter, Jan 13, 2021.

  1. Dan Winter

    Dan Winter New Member

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    Hello all. I recently got a Porta 07 and when I flip the switch to remix mode channel 3 is very faint. It records in fine and in cue mode it playbacks good but in remix mode it is so quiet I have two turn it all the way up and it's still barely there any suggestions on what the problem could be? Has anyone dealt with this before? I opened it up and don't see anything obvious like burnt components or shorts. I have a multimeter and know how to take readings and also know how to solder just a little unsure where to start. Thanks!
  2. SkywaveTDR

    SkywaveTDR Well-Known Member

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    Start by confirming the playback function but you will need alignment tape for that. Otherwise you will be shooting in the dark as to where the problem is.
    Dan Winter likes this.
  3. Dan Winter

    Dan Winter New Member

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    Okay sounds good any recommendation on where to get an alignment tape?
  4. SkywaveTDR

    SkywaveTDR Well-Known Member

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    The only place would be Genn Lab and what you need is a MXT116 as these are double speed.
  5. Dan Winter

    Dan Winter New Member

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    Thank you so much! I read your blog after asking the question and realize you recommend that company to those that ask you so I apologize for the monotonous question! I am going to order one as I want to get more into fixing these. However there is a plot twist. After looking at the schematic in the back of the manual I had a sneaky suspicion that the problem was on the mixer PCB and figured it would be worth just running the multimeter up and down it while I had it open and waiting for the alignment tape to ship. I discovered the linear potentiometer on channel 3 is bad which makes sense because the unit was very dirty when I got it. So perhaps this will fix the problem, perhaps not but the component definitely needs replaced. Do you have any idea what would be a good replacement component for this linear potentiometer?
  6. Dan Winter

    Dan Winter New Member

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    I can send a picture of the component if that helps as it seems I dont have permission to post a photo on here
  7. Dan Winter

    Dan Winter New Member

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    Okay sooo I took that slide potentiometer and opened it up and there was a big dirt ball on the contact part and a little rust so I cleaned it up and lightly used a Dremel to blow the rust off and BOOM! Channel 3 is working beautifully again in remix mode. All it was was a very very filthy potentiometer. Except now I have a new problem! When I first got the machine I recorded a little beat using a drum machine. The Porta 07 randomly one day started playing this beat back slowly. Even when I turned the pitch knob all the way up it still wasn't as fast it should be. Then magically it randomly went back to playing at the correct speed again. Except now it started doing it again where it is playing back to slow..... any thoughts?
  8. Dan Winter

    Dan Winter New Member

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    Also thank you very much SkywaveTDR you are an absolute beast!
  9. SkywaveTDR

    SkywaveTDR Well-Known Member

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    Speed changes like that can mean dirt in the Pitch control pot or that the motor and flywheel or capstan bearing has not been oiled recently. The motors are not real strong motors just enough to do the job. If bearing friction is bad then this will affect the speed. Several things to look into and hopefully it is not the motor. Oil the top bearing of the motor just under the pulley as it aims up and pull uo and down the pulley a little to get oil into bearing. just some ideas.