by Eddie Ciletti
This article will explain how to extend DA-88 head
life and improve adat
pinch roller pressure. It takes a delicate touch. More than
a few machines make it to my shop with missing screws, loose screws, chewed
up or busted screws and screws in all the wrong places. Sound like
a Country Song? Before going on a damage spree, please read the article,
to Use Your Tools."
The point of combining DA-88 and adat
information into one article is to demonstrate the effect of Springs.
is not safe to assume that the correct amount of tension or pressure —
depending on application, of course — is being delivered. Tension
gauges and jigs are expensive, but a little deductive reasoning and comparative
analysis will suffice.
Here are two examples….
Photo One: View of DA-88 transport showing reel tables and back-tension
Please note: This view is "upside-down" if the face plate is against
DISTRICT ATTORNEY: ATE E. ATE
Wanna know how to extend DA-88 head life? Pop the
hood and check the position of the tension spring. Photo One
is the "upside-down" view of the DTRS transport TASCAM uses in their DA-38,
DA-88 and DA-98. Older DA-88's may have the tension set too high.
Worse yet is that the fan may also contribute to increased tension by sucking
in dirt through the tape loading door. A check-up at 250 hours may
seem premature, but an early evaluation and a possible correction could
save a life.
EMPHATIC NOTE: DA-88
owners must reverse the fan and install an external filter. See
the Fan Modification Aritcle. Then have the transport thoroughly
cleaned and re-tensioned. It could mean the difference between 750 hours
and 1500 hours of head life. Despite what you've heard, a DA-88 in a clean
room environment can get up to 2500 hours of head life. The DA-38 and DA-98
have no fan and will therefore not have many of the problems suffered by
early DA-88 users.
Click here for more about
the DTRS family.
A warning before experimenting with the tension:
Check and document the total head hours as well as the error rate. Click
here to learn how to query the DA-88. Worn heads require more
tension to keep the error rate down, but new heads need almost no tension.
To adjust tension, loosen the two screws that secure the tension plate.
If the front panel is facing your chest, slide the plate to the left. Again
note that the image shown — Photo One — is upside-down, but that
the arrow indicates the correct direction. After making the adjustment
immediately check the error rate — not just of a previously recorded tape
(you’ll see only half the change) — but also on a tape formatted "post
Photo Two: Close-up of adat transport
detailing Capstan and Pinch Roller mechanism.
adat TIRE ROTATION —
of PINCH ROLLER PRESSURE could cause errors toward the end of a reel of
Increased errors toward the end of the tape — especially
after 35 minutes — could be an indication of insufficient pinch roller
pressure. This could very well be the case for an Original Formula "black-faced"
especially one that has 3,000 plus hours. Lots of adat
users regularly change the Pinch Roller along with other rubber
parts, but few consider that the spring responsible for the pressure might
be fatigued. At the time this article was written, the part number
for the spring had not yet been solidified. Call Alesis Technical
Support at 800-525-3747, ask for the spring by name and see if they've
created a part number for it.
HOW TO: Remove / Replace the PINCH ROLLER, ARM and
Rough handling during shipment could cause a "black-faced"
roller arm to come loose. which could potentially damage the heads. (Alesis
created a "shipping mode" for the XT that positions the arm so this
won’t happen.) Photo Two shows the clockwise
direction the pinch roller arm must be rotated to release it from the chassis.
The arm has a "claw" that restricts vertical — but not rotational — movement.
Rotate clockwise until the claw clears the cut-out or "key space" area
of the chassis, then lift up.
If dirty, clean off the contact areas with a cotton swab.
Be sure to re-apply lube that might have been removed by cleaning, but
do not overlube! (Lubriplate — a white, lithium grease — is available
at Radio Shack and MCM.)
Replace the spring and snap the assembly back into place.
Well, that’s it for now.
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