Dr. Tekkie, everybody's favorite electro-ombudsman, is never so busy in his gizmo-cluttered laboratory that he can't answer readers' questions about the mysteries of technology. But before we get to today's queries, we'll take a rare peek into Dr. Tekkie's File of the Curious:

A friend called me recently with an anguished lament. "My printer won't print!" she wailed. "What do I do now? Why do computers always bite the dust when I have a deadline?"

"The first question I can answer," I said, "but the second falls into the supernatural. May I suggest reading Jung on synchronicity?"

"Stow it, you nerd," she said affectionately. "I've checked the cables, the printer and the software. Everything's kosher, but the damn Mac and Imagewriter won't talk to each other."

"Aha," I said, sagely. "You're on a 512K Macintosh? Then I suggest you remove the battery and let it sit for 20 minutes before re-installing it." She made another bitingly affectionate comment about my intellect but complied with my unusual suggestion. A half-hour later she called to report her Mac and printer were again in harmony, tapping out reams of precious copy.

Here's the problem, one for which Apple Computer has no service bulletin: The battery in the older Mac (which powers the internal clock) also stores a small portion of random memory. Occasionally, for reasons unknown, the capacitors fed by the battery get confused (clogged with excess bits?) and freeze the system. Pulling the battery discharges the capacitors, freeing the printer and saving a service call.

Other computers have similar undocumented bugs. Readers: Let's hear about them.

Q. I want to tape radio programs when I'm not home. Is there a tape machine that can do for the radio what VCRs do for television? I haven't found a tape machine that will turn itself on in a record mode at a pre-set time or record more than one side of a 90-minute cassette (i.e., 45 minutes), which isn't long enough for a lot of good radio programs.

Christopher Buchanan, Arlington

A. You've uncovered a bit of techno-tyranny. Why shouldn't radio lovers be able to time shift, reordering their cultural lives as VCR owners do?

You're already in business if you own a hi-fi VCR with a stereo simulcast switch. Patch your AM/FM tuner or receiver into the VCR and use the timer to record only the radio signal. The VCR's sound quality will be better than a cassette deck's, and you'll have a longer recording time.

If you don't own a VCR (what true-blue radio fan would?), you'll need a cassette deck with an audio timer input and a switch that lets you select "play" or "record" when the timer is connected. Not all decks have this, so you'll have to shop around. An audio timer isn't the same as an ordinary electric timer, and it may have to be purchased from the manufacturer of the tape deck. Sansui, for example, sells its ATF-1 timer for $100. Onkyo, JVC, Nakamichi and others sell similar devices.

Absentee recording of both sides of an audio cassette requires a cassette deck with auto-reverse that works in the record mode. Quality machines with this feature start at about $650.

Q. All my reel-to-reel tapes emit a mechanical squealing sound. The tape deck seems okay. Could it be the tapes? They were in storage for a couple of years.

Walt Jenkins, Washington, D.C.

A. Audio tape and videotape are manufactured with a lubricant that may dry out with age. Squeaking also may be due to failed components in the deck's innards. To isolate the problem, play a new tape -- which shouldn't squeak. If it does, the problem is mechanical. You can also run the machine without tape, though you may have to fool the deck by bypassing a mechanical lever or photocell.

If you get squeaks sans tape, the problem may be caused by loose or misaligned reel hubs, which you might be able to tighten yourself, given a modicum of mechanical skill. Otherwise the squeal may be coming from faulty capstan bearings, idler wheels or any of several motors in the deck -- all of which should be checked by an audio technician.

Q. Is there any way I can ride my bicycle and listen to music? I never ride without my helmet, so wearing earphones is out.

Uneasy Rider, Falls Church

A. Congratulations on having the brains -- and caring enough about their survival -- to wear a helmet. The bicycle is a marvelous piece of appropriate technology (no other machine so efficiently converts human energy into mechanical power), but it's far more rugged than a human's relatively delicate anatomy. Most cyclists don't seem to realize that even a minor fall from a bike can mean permanent brain damage or death.

Using earphones while pedaling (or driving) in traffic isn't wise even if they do fit, because they are dangerous, not to mention illegal in many places. Besides, bicyclists have enough to worry about (as do joggers and walkers) without increasing their risks by spacing out. Several products can help you exercise more safely and harmoniously:

TUNE-Tote ($25) is the first stereo-speaker system for bicycles. The handlebar-mounted unit consists of two speakers attached to a platform on which you clamp your radio or cassette player. A second model, TUNE-Tote 2 ($35), has battery-powered amplifiers for more volume and crisper sound. Speakers for both models are weather-resistant, says the manufacturer (Novi Inc., 7920 Silverton Ave., San Diego, Calif. 92126; 619-549-6610), but not waterproof. Bring along a big plastic bag if you plan on singin' in the rain.

Safe & Sound ($50) is a scarf-like device with a built-in FM radio. The manufacturer claims draping the gadget around one's neck (it rests on the collarbones) provides better stereo quality than earphones.

Stereo Sweats ($60) is a hooded, zippered sweat shirt with removable stereo speakers in the collar, letting you hear music without covering your ears or cutting yourself off from ambient traffic noises. The Stereo Jacket ($70), a nylon windbreaker, is similar. (Safe & Sound, Stereo Sweats and the Stereo Jacket are all made by Sport Electronics Inc., P.O. Box 1412, Northbrook, Ill. 60062; 312-564-5575.)

Stereo Sweats and the Stereo Jacket have fully enclosed wires (no trailing or tangled cords is an additional safety factor) and a jack you plug into your own tape deck or radio. Which leads me to wonder if we'll eventually see and hear people wearing Stereo Sweats on the Metro. Can you imagine asking a guy to turn down his sweat shirt? ::

Address questions to: Dr. Tekkie, The Washington Post Magazine, 1150 15th St. NW, Washington, D.C. 200071.