Cleaning and touch-up
I did not say “restoration,” since that’s a whole other subject, although I did touch on fixing up speakers by replacing a bad driver which is pretty straightforward. Electronics restoration generally implies aligning tuners and replacing/upgrading internal components beyond simple lamps and fuses and a good cleaning, which is beyond the scope of this article.
The exception might be a “modest rehab” through selective replacement of the unit’s capacitors, depending on how electronically-handy you are. If you’re interested in going that far, I’ve an engineer friend who recommends DigiKey as a source for any caps you might need: http://www.digikey.com/
What to have on-hand for cleaning
Armor-All for general rubber and plastic maintenance.
Simple Green (for knob and switch cleaning)
Goo-Gone or Goof-Off solvent for really stubborn labels and stickers. Some people put labels on controls and when they’ve sat there for three decades they can be pretty anchored.
Isopropyl Alcohol 70% for general cleaning of glass and faceplates.
The three specialty chemical items below are available from Vetco Surplus Electronics in Bellevue, Washington http://www.vetco.net/index.php Vetco has lots of military-grade electronics chemicals you probably never knew existed. They also stock virtually every fuse and bulb made for electronic components, which is good to know. You may find a local place with similar products, but if not Vetco sells on-line. Note: Anhydrous alcohol and other industrial-grade chemicals can’t air-ship so allow time before a project.
Isopropyl Alcohol 99.95% anhydrous for really thorough cleaning, especially jacks.
Rubber Renew for more serious conditioning and renewing of old rubber.
Control/contact cleaner spray (sometimes called tuner cleaner) for cleaning out controls and switches.
Other cleaning items to have on-hand
Cotton swabs for very fine cleaning around switches and corners.
Cotton balls (they don’t leave fibers behind like tissue will)
Canned air duster for blowing dirt and dust out of the chassis.
The following is available from Music Direct http://www.musicdirect.com and is indispensible for cleaning back-panel input jacks.
Signet RCA cleaning tool (use with the anhydrous alcohol)
For touch-up work, I use the following:
Sharpie markersâ€”these are great for touching-up black finishes and even black speaker veneers. You swipe the area of the scratch or blemish, then rub it off and repeat until it fades in.
Wood-grain repair sticks or “pencils” for fixing scratches, gouges and chips in speaker enclosures and cabinets. MinWax makes a full line from light oak to dark walnut; you can find them in any Home Depot.
Other items: Along with standard tools, I also recommend having an assortment of fuses on-hand and an FM dipole antenna for checking operation.
Getting into it
At this point I am required to insult your intelligence by reminding you to be careful and never open an electronic component as there are no user-serviceable parts inside and don’t try this in the rain or while standing in water. But there are three safety items I do want to share with you.
Wear goggles or safety glassesâ€”when spraying out controls with contact/tuner cleaner, it’s really easy to get a back-blast of the stuff in your face in such close quarters. And trust me, you don’t want to
Wear Nitrile gloves especially when handling anhydrous alcoholâ€”this stuff is nasty and will dry your skin out faster than you can say “Palmoliveâ€”you’re soaking in it!”
Be wary of unplugged componentsâ€”big old honkin’ power-supply capacitors can store a charge for quite some time and will definitely get your attention if you brush against the right contacts on a board.
Also, be wary of the plug itselfâ€”in this case the unit’s original AC cord which may be worn and need replacing (more on that later).
Once you’ve checked the unit out and have decided to keep it, how you go about cleaning it up is up to you. It’s kind of like ironing a shirtâ€”I’ve no idea why I start with the sleeves while others prioritize the collar, but this procedural sequence works for me and may for you.
A lot of what happens is removing dirt, and in this case dirt is your friend. I’ve noticed that the dirtiest units are usually the most scratch and dent free, maybe because they sat in one place for a very long time.
Cleaning up electronic audio components
Knobs and switches: before I open-up a receiver, amplifier or other electronic component, I pull off every knob and switch possible. Some have small set-screws holding them onto the shaft, check before pulling. A rubber kitchen jar-opener can help in getting a good, safe grip on a reluctant knob without causing any scratches or damage.
Since knobs usually have an indicator mark on them (think of the “0” center position on a bass, treble or balance control) it helps if your turn the controls to one extreme (left or right) before removing. That way you don’t have to remember which way they slide back on later.
Take all the knobs and switches and put them in a shallow bowl with an inch or so of Simple Green and let them soak while you work on the rest of the unit. When you rinse them off with hot water they’ll be clean.
Cabinet: after double-checking to make sure the component is unplugged from AC, remove it for cleaning the rest of the unit. Some units have screws on the bottom and rear as well as the sides, watch for that. Usually the cabinet is wood-veneer or vinyl. The latter can be cleaned with a little soap and water. The wood repair pencils will come in handy for any scratches.
Chassis: take the unit outside (trust me on this) and, using the canned air duster, blow everything out. Be careful around tuner assemblies, and try not to blow dust into anything. I actually use a car vacuum and brush gently first to pick up the gross debris, being careful not to actually touch any circuitry.
An oldie-but-goodie stereo receiver packs a lot of rear-panel “heavy metal”â€”this mid-70’s Kenwood has 17 RCA jacks and 12 speaker terminals. The RCA cleaning tool is a must for removing oxidation. I use a broken one (missing the central post) for cleaning speaker terminals. Don’t forget to check the AC cord’s integrity while you’re at it.
Faceplate: the 70% alcohol is good for most cleaning, but be careful on some function labelsâ€”sometimes alcohol removes them depending on the screening process used. Windex is safe in that event. In really dirty areas (volume control areas often have years of grimy finger grease stains around them) use the 99% anhydrous alcohol if needed. I use cotton balls for faceplates and tuner and meter glass, and swabs for getting into the tightest places, especially around push-button switches. Don’t neglect headphone and microphone jacks on the front panel.
For scratches in plastic, an abrasive toothpaste is actually a good way to buff some of it out and make it look better. Test it in an unobtrusive area first and go easy, using a cotton ball and a little water for dilution.
Some faceplates can be easily removed, but others are on for good unless you’re doing a major refurb. With the materials I mentioned you should be able to bring them back to near-new condition either way.
Controls: you’ll want to clean out every rotary and sliding control, since that will remove much of the noise and scratchiness you hear when using them. The Contact/Tuner cleaner spray can should have a small pipe which fits on the spay head to provide a very fine outlet, similar to a WD-40 can. Look at the volume, balance and tone controls inside the unitâ€”each shaft goes into an assembly with the control components inside, and there should be a small opening or hole on each which the contact cleaner’s spray-head pipe should just fit into.
Spread some newspapers under the unit first, since the contact/tuner spray can run down through bottom vents. Spritz some spray into the control while quickly turning the shaft back and forth to get the control fully cleaned and lubricated, and repeat for the other controls (on sliders, slide the control back and forth). If there is a large tuning capacitor you can spray that as well.
[Above left] You’ll spray controls with Contact/Cleaner while rotating the front-panel knob at the other end of the control’s shaft back and forth, to make sure the spray penetrates. Look for a small access hole in the control body. Sliding controls [above right] are cleaned the same wayâ€”move them back and forth while spraying the control’s body behind the panel
Fuses and lamps: like I said earlier, I usually replace any internal fuses on general principles. Audio gear always uses AG fuses which stands for “all glass,” and they look like a small lamp (in fact on some gear fuses and lamps may look identical). This is the same style of in-line fuse you see on car stereo equipment. If they are in hard-to-reach places you can carefully use needle-nose pliers, taking care to lift by the metal end and not the glass of course.
Indicator and dial lamps come in two varieties, the kind you mess with and the kind you don’t. The second type are those hard-wired purpose-built types that require unsoldering. They usually have an integral plastic or rubber collar. Unless you are thoroughly refurbishing a unit I’d leave them alone. Fortunately, many older components use more standard lamps, including the ones that look like AG fusesâ€”you just snap them into holders. You may find replacements at Radio Shack, but if not places like Vetco and Vintage Electronics probably have the one you need.
Don’t be nervous if you can’t find an exact match for the original lamp’s voltage. Getting close is enough as long as you leave some room. For example, if the original is labeled 5 Volts and you can only find a 6 Volt replacement in that size, that’s fine. A great on-line source is Vintage Electronics http://www.vintage-electronics.cc/index.html (they carry parts for turntables and tape decks as well).
Also, check other sources. I was frustrated trying to find a set of replacement lamps for a Sony receiver that looked vaguely familiar. Then someone in an electronics store pointed out that they were, in fact, European-style automotive lamps. My old BMW used them in the dome light assembly, which is where I’d seen them before! I found a set of the exact lamps I needed for the Sony at the auto parts store around the corner.
Reassembly and final steps: rinse off your knobs and switches, and replace them after they’re good and dry. As a next-to-last step, you should clean out all the RCA jacks on the rear panel, and a typical older receiver or integrated may have at least 16 or so RCA input/outputs. Use the Signet RCA cleaning tool for thisâ€”just dip it in the anhydrous alcohol and ream out each jack. It removes all oxidation and leaves the jack looking new.
Finally, before putting the cover back on check the AC cord’s condition. If it is cracked or compromised anywhere you might want to replace it (and its strain-relief/grommet part if possible) before reassembling. Often old AC cords can be brittle and have small breaks in the insulationâ€”check carefully. Radio Shack sells good AC replacement cords or you can get them at any electronics supply outlet. If the cord is OK, you might wipe it down with Armor-All to get it shiny and pliant, and also Armor-All the unit’s rubber feet to make them look refreshed.
Once you’re satisfied with the unit’s condition, put the cover back on and check everything out again.
Other types of components
Speakers: they should be cleaned very gently, and never with alcohol which can damage rubber surrounds. I usually swab Armor-All around rubber surrounds and gaskets. If the enclosure is a real wood veneer you can use furniture oil, if not Armor-All works well (wipe it off after applying). Make sure you do any touch-up before wiping the enclosure. If you decide to replace any drivers, make sure you match both size and basked style (round, pin-cushion, etc.) for a close fit. Madison and Parts Express both carry replacement drivers as well as gasket material, grill parts, and rubber feet (you can use these on electronics as well if any are missing).
Dust covers: I haven’t covered turntables (or open-reel tape decks) which are the prime application for dust covers, since I’ve yet to find a decent turntable in a thrift store. But if you do, you’ll probably hate whatever’s left of the original dustcover. An outfit called TAP Plastics http://www.tapplastics.com/ has locations all over the west coast and does business on-line, and can build you a new cover that will look better than the original (one of theirs is sitting on my Thorens 125 turntable which was a hand-me-down). They do their best work if you can send them the original, even if it’s broken, but they can work from measurements as well. There are plenty of sources for turntable parts, but dustcovers are impossible to findâ€”this is a great resource should you need one.
If you pick up any classics this way you want to show off, please take a photo and share them with us here along with some details on how you found it. And if you come up with techniques and materials of your own, by all means let us knowâ€”anything to advance the emerging art of rescue audio.
Before 27 years in corporate marketing roles for Xantech, Leviton, Carver, Harman/Kardon-JBL, and Bose Corporation, Mark Cerasuolo worked in audio retailing going back to part-time jobs in college. A lot of his audio “new finds” in thrift stores are old friends he couldn’t afford way back when. In 2010 he became the “first fully online undergraduate student to deliver a student commencement address at a traditional four-year college or university” at the University of Massachusetts in Amherst, proving that one can drop out to pursue an audio retailing and marketing career and still have it work out in the end. Mark is active in CEA, most recently with the Multi-Room Audio/Video group. He lives in Redmond, Washington, with his lovely and understanding wife Dawn.