How to tell if tape heads are good?

Discussion in 'Tape' started by blhagstrom, May 14, 2017.

  1. blhagstrom

    blhagstrom Mad Scientist, fixer. Subscriber

    Messages:
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    Location:
    Duvall, Washington
    I get a lot of tape decks to flip.
    People ask for photos of the heads.
    All heads look OK to me.
    I can understand commercial decks that may have passed millions of miles of tape and may show track wearing, but consumer heads?

    What are they looking for?

    Any photos of "bad" heads out here?
     
  2. KevinJS

    KevinJS Super Member

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    1,940
    Location:
    Canada
    Run your fingernail across the head. If you can feel a ridge, the heads are worn.
     
  3. blhagstrom

    blhagstrom Mad Scientist, fixer. Subscriber

    Messages:
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    Location:
    Duvall, Washington

    I assume perpendicular to tape travel? Looking for the ridge left by the tape stream.

    And, assuming there is any feeling left in my fingers or that my nails are worth a damn.
     
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  4. KevinJS

    KevinJS Super Member

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    1,940
    Location:
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    Yes to both points.
     
  5. blhagstrom

    blhagstrom Mad Scientist, fixer. Subscriber

    Messages:
    11,861
    Location:
    Duvall, Washington
    Looking closely at a junker I have here.

    I see under a good light after a good alcohol cleaning that they look rough in the tape contact.
    Now I see wear on a guide pin.

    I think these are shot. Or at least unusable as is. I've heard of re-lapping but that's a bit advanced as a selling point.
    Just another heavy piece of junk.
     
  6. Grbluen

    Grbluen AK Subscriber Subscriber

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    2,102
    As much as I hear about the smoothness of heads, I also hear about the "dreaded opening of the gap". What causes the gap to open?
    Thanks
     
  7. dhnash

    dhnash Active Member

    Messages:
    179
    This website has much information that may help you to understand this term.

    http://www.jrfmagnetics.com/

    The section on head reconditioning includes a cross-sectional drawing of a typical tape head. A open gap condition is reached when wear of the tape head reaches the point where the gap spacer is no longer held between the two poles of the head.
     
  8. Grbluen

    Grbluen AK Subscriber Subscriber

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    2,102
    Thanks!
     
  9. oldvinyldude

    oldvinyldude AK Subscriber Subscriber

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    Location:
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    Some consumer decks got heavy use in the day. Some head materials were not as hard as others, so significant wear is often found. Akai "glass" heads were very durable, but sometimes failed in their own unique way. Even some cassette decks suffered from excessive head wear-mostly earlier models (say, mid 70's). The slow tape speed was a plus in their case, as wear is a function of head hardness and total tape length traveling across the heads. Some tape formulations are reported as being more wearing of heads, although I have never seen an actual set of test data to support this claim.

    The JRF magnetics link does an excellent job teaching one about heads, wear, etc., etc.
     
  10. Rey1

    Rey1 Well-Known Member

    I found a high end Teak RtoR in a local GW about a year ago. it looked fantastic but the heads had a huge groove worn in them, deepest I have ever seen. It looked like a gorge! Such a shame.
     

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