Troubleshootin' Cowboy Rules of thumb that can extend the life of your A/V products. By Patrick Killianey There was a time when audio video equipment was repairable. Back then, a hi-fi was considered a piece of furniture. Our family's system was set inside a solid oak hutch that also housed the radio tuner, amp and speakers.

Recently, I brought some aspiring engineers to a trade show where one such antique was on display. They described it as “way cool” and proceeded to explain to each other how this was obviously James Bond's personal rig, since it was so well disguised.

Over the last 30 years, A/V equipment has certainly followed the better-smaller-cheaper model of the computer industry. But like the computer market, repairs aren't typically done at the part level. If the laser in a CD player goes bad, the chassis with the whole drive motor and optical track will typically be swapped out.

At this point, it's probably safe to say that for A/V decks, the bag of tricks for in-the-field repair is limited to smelling for burned electronics, scanning for loose wires, and the tried and true whack on the side of the box. However, there are a couple handy tricks for recovering damaged media. Plus, there are some maintenance rules of thumb that can extend the life of your products.

SPECIFYING CD PLAYERS

The most frequent problem with CD and DVD players today is media compatibility with CD recorders. Recordable CDs were never part of the CD specification, and most available CD players were not designed with CD-Rs in mind. Therefore, there are some caveats with media compatibility that may never be completely resolved. While the general public is becoming more educated on the various media, there will always be a few users who try to put a CD-RW disc in a standard audio CD player.

That being the case, it is helpful to install a CD recorder instead of a CD player. After all, CD recorders also act as CD players, and the price gap between decent CD recorders and decent CD players is shrinking.

By using a CD recorder, you'll greatly reduce the number of media compatibility issues. And you'll also be including the handy ability to record a CD. As a side benefit, some audio CD recorders are built around more robust computer CD-RW drives for recording mechanisms, which will extend the life span dramatically.

DVD EQUIPMENT

The price difference between DVD players and DVD recorders is a bit more staggering. The first generation of DVD players could not read CD-R or CD-RW media at all, let alone DVD-R media. Newer players offer the ability to read CD-R and DVD-R discs, which greatly enhances their usefulness.

It was only in January of this year that Apple announced the bundling of a DVD-R/CD-RW SuperDrive with its most powerful G4 processor. Since then, the price of bare DVD-R drives has fallen from $5000 to $1000, which makes them much more suitable for installs.

Given the new availability of affordable drives for one-offs on DVD-R, it is reasonable to expect a serious surge in video for presentations burned on a DVD-R. Next time a bid comes up that requires a DVD player, make sure the specified player reads CD-R and DVD-R media, at the very least.

OPTICAL DISC REPAIRS

When CDs first came out, everyone held their breath while handling these shiny discs only by the edges. We gently placed them into the player with the level of care typically reserved for open-heart surgery. Today, we'll do our best Frisbee throw across the room. As the technology becomes familiar, our CD and DVD media are getting more scratched up than ever before.

Most people know that scratches following the circular reading pattern on the CD will be more likely to cause a problem than scratches that are perpendicular to the reading pattern. What most people don't know is that the scratch itself is not usually the problem.

There is a clear protective layer on the CD's read side, which guards the data layer from damage. Since the player's optics are normally focused beyond the protective layer, the systems typically read past the scratches. (See Figure 1.)

Figure 1. CD Layers. The data layer of a CD is simply a reflective piece of aluminum, with a protective lacquer on the back and a clear polycarbonate on the top.

The problem actually comes from the dirt that collects in the nooks of the scratched area; the dirt is what the laser can't read through. The way to solve this, oddly enough, is to wash the CD or DVD, much like you would a dinner plate.

Using cold water (so the plastic doesn't melt), take a sponge with some dishwashing liquid, and wipe from the center of the CD to the outside. Don't wash in a circle, since that might cause new scratches that follow the reading pattern. To dry the disc, dab it with a soft cloth. Then put it in your ROM or player. Chances are, it'll work.