DA-88 Maintenance, Upgrades and Tweaks
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DA-88 UPGRADE LIST

Figure 3: A hairline fracture of the slide cam lever can cause fast wind failure (S-error 31/41). (Click for larger view.)

You might be surprised at how many DA-88s still have their original heads. This is not a comment on the machine’s genetic disposition, just an indication that some older, low-mileage machines come in for service needing many of the factory upgrades. I still get them. DA-88s before serial number 100000 were made around 1993-ish, while serial number 320000, for example, is circa 1995. The fifth- and sixth-place digits are lot numbers. In these examples, lot 10 and lot 32, respectively. If you own or encounter one of the older, low-mileage decks, then it should be overhauled sooner rather than later.

Here’s a partial list of DA-88 updates (with an error message in parenthesis when applicable).

1. self-cleaning kit: This two-part kit consists of a sharp Ruby “scraper” that is highly effective at removing loose debris from the tape before it gets on the heads. A second rather annoying sub-assembly periodically dabs the heads in an attempt to clean them.

2. slide cam: This simple piece of plastic engages the brakes and tightens the clutches. The difference between old and new parts is a smoother transition to a notch that sets up the Fast Wind mode.

3. slide cam lever/actuator: (S-err-31/ 41) There are three possible Fast Wind failure modes: bad solenoid, bad solenoid circuit (cold solder joints) and a damaged lever arm, the latter caused by a fracture at the bend in the metal work. The crack is hard to see, even when you know it is there. See Fig. 3.

4. reel tables: Redesigned three times, and one of the primary annoyances is the interaction of the black optical encoder disc with the lower portion of the reel table clutch. Over time, the black shaft compresses and creates friction. The new reel table design seems to have solved this problem.

5. cam and sector gear: (S-err-11) A limited run of DA-88s—with serial numbers between (approximately) 240000 and 360000—suffer from this “stuck loading guide” error message. Under-spec pin length causes damage to a plastic cam.

6. back tension coil spring: When replacing the back tension felt, a “silver” coil spring on the underside of the assembly ensures positive contact with the tension lever position adjustment mentioned above and detailed in Fig. 2. This spring was modified both to facilitate reassembly and to ensure positive engagement.

7. back-up battery: The three VDC lithium backup batteries should be periodically checked to make certain it measures 2.6 volts or higher. Even more important, inspect for leakage before circuit board damage is beyond repair. I use a different battery than recommended, because its vapor seal minimizes “battery exhaust” that can eat copper circuit traces.

8. slant blocks: The slant block is the lower portion of the loading guides. When there isn’t a tape in the machine, they are loose to the point of seeming to be broken. This is normal. They become “precise” once fully extended and pressure fit against the “V” guides. Slant blocks are perhaps the most mysterious parts in all digital audio recorders, because they are difficult to measure and there are no adjustments except for guide height. There should be a front-to-back tilt adjustment to minimize curling, especially in the exit guide.

9. lubricant: For all helical tape transports—DAT, ADAT and DTRS—any lubricant applied to the loading guide paths should be wiped clean, leaving only a molecular layer. Tape that accidentally becomes slack and makes contact with the lube will become very attractive to a head spinning at 2,000 rpm!

For more information about maintaining your gear in top shape, visit Eddie Ciletti's Website at www.tangible-technology.com

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