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Author Topic: Modified Otari w/scraping Noise  (Read 5327 times)

Offline Grant99

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Modified Otari w/scraping Noise
« on: December 03, 2009, 12:08:26 PM »
So I finally got those rubber spacers so I can play the larger reels on my Otari MX-5050 (w/modified tape path by BH).  And my new repro sounds great!  I can't believe how great some of my old 4 track tapes sound on it!  I've never heard Al Hirt sound so good!

Just one issue: when I play tapes (both 7 inch & NAB reels) I hear this scraping noise.  As it turns out, its the sound of the tape edge scraping against the white washers on the take-up side tape tensioner arm.  The tensioner arm is the BH modified one, where the tape runs between 2 white washers that serve as guides.  When you press against the inner washer, to move it away from the tape edge, the sounds stops.  And as the tape runs through the path on the arm, you can see a crease on the tape.  This makes me think that the tape path is just a tad too narrow.  I'm also getting quite a bit of ferric residue/dust on both arms & actually all along the entire tape path, that I never used to get before.

So I'm wondering if anyone else around here with a modified MX-5050 has seen this.  If I widen the tape path on the arms with it affect the sound?  Also, I'm a bit concerned about wear on the tapes, what with all the dust/residue I'm seeing in a short amount of playing time.

Any comments/suggestions will be appreciated!
regards
Grant
Grant Thrasher
audio/LP/tape hobbyist
Otari MX-5050 BIII, VPI-19/SME IV, MFA Magus/MFA D75 amp/McAlister EA-8 amp/Stax OA2 & SR-404/Coincident Millenium Spks/Nak Dragon/Marantz PMD520/Sony KA1ESA

Offline docb

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Re: Modified Otari w/scraping Noise
« Reply #1 on: December 03, 2009, 12:46:43 PM »
The spacing between the edge guides is done with precision shims interleaved with the precision ball bearings and it is fixed to be slightly bigger than the width of the tape. The arm itself may have gotten tweaked a bit, this is very common. Look at the arm and see if it is parallel to the front panel of the machine or if it is a little angled. That guide has been modified to be adjustable because those arms are kind of flexy. If the arm looks tweaked try straightening it a little. You can also try turning the nut on the front of the guide a bit clockwise, to move the guide "in" a little.
Dan "Doc B." Schmalle
President for Life, Bottlehead Corp.
Managing Director - retired, The Tape Project

Offline Grant99

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Re: Modified Otari w/scraping Noise
« Reply #2 on: December 04, 2009, 09:10:22 AM »
If the arm looks tweaked try straightening it a little. You can also try turning the nut on the front of the guide a bit clockwise, to move the guide "in" a little.

Thanks Dan, I will give this a try.  But I'm not sure how to straighten the arm; could you perhaps be a little more specific.  Thanks again.

Grant
Grant Thrasher
audio/LP/tape hobbyist
Otari MX-5050 BIII, VPI-19/SME IV, MFA Magus/MFA D75 amp/McAlister EA-8 amp/Stax OA2 & SR-404/Coincident Millenium Spks/Nak Dragon/Marantz PMD520/Sony KA1ESA

Offline docb

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Re: Modified Otari w/scraping Noise
« Reply #3 on: December 04, 2009, 09:17:14 AM »
Have you determined that the arm is, in fact, bent? If it's not obviously out of parallel with the front of the deck just adjust the nut to move the guide a bit so that the tape runs through it without hitting on one edge.
Dan "Doc B." Schmalle
President for Life, Bottlehead Corp.
Managing Director - retired, The Tape Project

Offline Grant99

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Re: Modified Otari w/scraping Noise
« Reply #4 on: December 04, 2009, 09:29:36 AM »
It sure doesn't look bent from what I can see.  So I will try adjusting the nut to get guides to move a bit.  Thanks again.
Grant Thrasher
audio/LP/tape hobbyist
Otari MX-5050 BIII, VPI-19/SME IV, MFA Magus/MFA D75 amp/McAlister EA-8 amp/Stax OA2 & SR-404/Coincident Millenium Spks/Nak Dragon/Marantz PMD520/Sony KA1ESA