Hi * First, confirm that your problem is not simply due to a selector switch in the wrong position or an accidental press of a key selecting 'VCR' instead of 'TV'.
* If your 'problem' unit is a universal type, make sure it has not simply forgotten its programming or codes - reinitialize it. A common cause of memory loss is the batteries falling out or losing contact for an instant due to a fall or bump. See the section: "Forgot your universal remote setup?". * Some older TVs in particular may have a 'vacation' or other switch to disable the set (or just the remote functions). For that matter, if you cannot get the equipment to turn on at all, make sure it is plugged into a live wall socket :-). * Some TVs may occasionally become confused due to a power surge or for no good reason at all. Unplug the TV for a few minutes to reset it. * Before doing anything else, check and/or replace the batteries with fresh ones. Who knows how long they have been in there. * Don't ignore the possibility that your spouse (or the local poltergeist) accidentally dropped the remote spilling the batteries - and put some back in backwards! This could result in either a totally non-functional remote, weak (limited range), or erratic operation. Permanent damage is not that likely but possible with some designs if the resulting voltage to the circuit board actually had reverse polarity. * Next, try to determine whether the problem is indeed in the remote itself and not the TV, VCR, CD, or other controlled equipment. The easiest way to do this is to temporarily program a universal remote to match your equipment. If this now operates successfully, then you can be pretty certain that the problem lies in the remote unit. * If you are not able to get a universal remote to operate your equipment, then either you have not found the proper code setting or the remote itself is indeed faulty (or you don't have a universal remote!). * Should you or a friend have an identical or nearly identical piece of equipment, try the (faulty) remote on that (and its remote on your equipment) as a further test. * If you have multiple pieces of equipment, make sure you have not accidentally substituted an apparently identical remote for a slightly different model VCR, for example. Not all equipment - even of similar type - from the same manufacturer necessarily use the same signal transmission format. Diagnosing the problem: ---------------------- To narrow down the problem, use an IR detector to determine if the remote is emitting an IR signal when each button is pressed. While this does not guarantee that the signal is correct, it eliminates most common problems from consideration. An IR detector card or an IR detector circuit like one of those described in the section: "IR detector circuits" are very handy for testing remote controls and other IR emitters. Some camcorders (those that do not incorporate an IR blocking filter) are sensitive to IR as well and will show a bright spot of light if aimed at a working source of IR. cards for $7.29 each (#72-005/3.5 x 2.5" card & 72-003 /4.75 x 0.75" probe. The salvaged IR sensor module from a TV or VCR may also be used as an IR detector. These usually operate from a single supply (12 V typical) and output a clean demodulated signal - you will not see the carrier, only the 1s and 0s. This will be true of an IR detector circuit as well unless you are careful to position the remote and photodiode just so as the circuit acts as somewhat of a low pass filter due to the B-E capacitance of the transistor. Radio Shack and Digikey (among other) also sell inexpensive IR receiver modules (under $5) which would also provide a demodulated signal for your viewing pleasure. However, note that some may be tuned for a particular carrier frequency like 40 KHz and therefore may not respond to all remotes. (Note, I have heard of spurious pickup issues with some of the Radio Shack units - they are not the same as those sold a while ago.) output can then be viewed on a scope or used to drive a small transistor which would in turn drive a speaker! The output from the MOD1 is the inverse of the code sent. That is, the TTL logic level from the MOD1 is high when no IR is present. If by chance you need an IR receiver that operates on a different types for sure. Remote repair: ------------- Most problems can be remedied without any special skills. However, where bad connections or component replacement is involved, you will have to be able to do just a bit of fine soldering. In this case, a low power (e.g., 25 W) fine tip soldering iron and fine rosin core solder will be needed. Fortunately, the circuit boards in remotes are generally constructed using features sizes (pads and lines) that are state-of-the-art from the 1950s. Therefore, rework isn't nearly as challenging as, say, on your 500 MHz PC! CAUTION: You can easily turn a simple repair (e.g., bad solder connections) into an expensive mess if you use inappropriate soldering equipment and/or lack the soldering skills to go along with it. If in doubt, find someone else to do the soldering or at least practice, practice, practice, soldering and desoldering on a junk circuit board first! See the document: "Troubleshooting and Repair of Consumer Electronics Equipment" for additional info on soldering and rework techniques. Test equipment beyond a good eye and maybe a multimeter is rarely needed. The most challenging part of repairing a remote hand unit may be just getting inside! Manufacturers seem to pride themselves on the extent to which this is becoming more nearly impossible without dynamite: * Screws - Some well designed (from the point of view of repair) units have a screw or two in obvious places (back cover and/or inside the battery compartment). Once removed (generally with a proper fine tipped Philips blade screwdriver), the two halves of the case come apart, possibly after sliding one with respect to the other a fraction of an inch. * Hidden snaps - If no screws are visible (and even after removing them in some cases), it will be necessary to carefully examine the seam and possibly inside the batter compartment to determine where the likely locations of plastic snaps. Running a butter knife or similar thin tool along the seam may persuade the unit to pop in half. * Glue - I don't know if any remote controls use this more-or-less permanent approach but if so, careful use of a hacksaw may be necessary :-(. Even if the case is slightly damaged after disassembly (e.g., a snap or two break off), the sparing use of a semi-permanent adhesive like windshield sealer will probably be able to fasten it all back together in such a way that little evidence remains of its traumatic experience. Problems with remotes: --------------------- Most problems occur in the hand units due to the abuse inflicted on them by kids, pets, and even otherwise well behaved adults. However, the equipment or even outside interference can also be at fault. and suggested solutions. As noted, most are physical in nature: dead batteries, gunk, bad connections. For all but the first two, disassembly will be required. Manufacturers seem to be using more and more creative (read: obscure and difficult to open) methods of fastening the two halves of the remote shell together. There may be a screw or two and/or the case may simply 'crack' in half by gently prying with a knife or small screwdriver along the seam or sliding the two halves a fraction of an inch to unlock some catches. Look for screws on the back (possibly under a not-so-easy to peel off label) and inside the battery compartment, as well as hidden snap fasteners. Dead batteries or batteries inserted incorrectly: ------------------------------------------------ Solution obvious. If batteries tend to go dead quickly - the batteries in a remote typically last years - then you may have a stuck button, some conductive grime under one of the buttons, or a defective IC - or you may be using cheap batteries. Make sure that all the batteries point in the correct direction as marked inside the battery compartment or under its cover. If it uses more than 2 batteries, getting one in backwards could also result in weak or erratic operation. Corroded battery contacts: ------------------------- Clean off the chemical deposits - first dust out the dried material with a soft brush and then remove the remainder with a damp lint free cloth or paper towel. Polish the contacts with a fiberglass brush and/or pencil eraser and/or very fine sandpaper or a nail file. If there is evidence that the battery juice made its way inside the case, you will need to open the remote and thoroughly clean the interior. Additional repairs may be needed if damage to wiring, components, or circuit board traces is evident. Broken or intermittent contacts: ------------------------------- There are most often between the battery connections and the circuit board. Carefully resolder and reinforce them if necessary. There could also be cracked solder joints on various component pins (particularly those that get abused like switches) as well. Reflow the solder on any suspect joints. In addition, check selector, power, or enable) switches for proper operation. Remove the batteries and use an ohmmeter to test across the contacts with the switch(es) in all positions. These switches can be easily damaged as a result of dropping or squashing the remote. The contacts may become dirty, gunked up, corrode, or simply wear out as well. Locating a replacement may prove challenging. Disassembling the switch may allow you to clean or restore the contacts in some cases. Broken Ceramic Resonator: ------------------------ These may fail from shock when remotes are dropped. The frequency is often 455 KHz (I assume since they are widely used as filters in the IF section of AM radios and are thus inexpensive.) If you have an oscilloscope, check for signals on the IC when buttons are pressed - if there is no action on any pin, then you may have a bad resonator (or bad IC, etc.). Monitoring on one lead of the ceramic resonator should produce a signal at its resonant frequency when a button is pressed. A typical waveform may have an amplitude of a few tenths of a volt. If you do not have a scope, one possible indication of a bad resonator (aside from it being smashed) would be a steady output from the IR LED for all button presses - normally the output would be visibly pulsating. Of course, this could indicate a bad IC as well. A ceramic resonator usually is a small blue or orange object that looks similar to a plastic (sharp edges) or dipped (smooth edges) capacitor. The circuit board marking will be X1 or CR1 or something like that. Replacements may be available from places like MCM Electronics or other electronics distributors. Or, consider an organ donation from a remote for equipment that has long since gone to that entertainment center in the sky if the frequency of its resonator is the same. Dirt/spills/gunk/oily buildup inside: ------------------------------------ This may cause circuit problems preventing keys from operating reliably or physical problems resulting in keys being just plain stuck or sticky. * If you have recently cleaned the outside with a wet or damp cloth (or in your dishwasher!), then this is quite likely as liquid can seep inside and result in all sorts of strange behavior immediately or delayed by some time. * Disassemble completely and wash both sides of the rubber membrane keypad, circuit board, and plastic case with water (and mild detergent if necessary) to remove sugar based grime and then isopropyl alcohol. Dry thoroughly. * For stubborn crud, a pencil eraser and/or fiberglass brush may be used with care (on the circuit board only). However, the gold plating (if present) and/or copper trace itself is quite thin! * Where you find a oily film between the rubber and the circuit board, unless you really do a SUPER job of cleaning, it will come back quickly. It may come back no matter what you do. Once you think you got it all, do it again - and with soap and water as well - both the rubber and circuit board. This goo may originate from a number of sources (no one seems to know for sure) including: body oils, spills, plasticizers from the flexible keypad, protective grease, etc. Unless you had dunked the remote in a vat of motor oil to create this problem there may be no sure way to prevent it from returning in the future. Caution: In some cases, the conductive black material may be soluble in alcohol - carefully test first on the pad of a key you don't care much about. If black material comes off on your cloth or swab, use only the water and detergent. Putting the black stuff back on is much more difficult than removing it :-). Worn or corroded pads on circuit board: -------------------------------------- These may be interdigitated or semi-circular patterns and suffer from both wear and corrosion. Conductive Epoxy or other similar conductive paint (like that used for rear window defogger repair) or ink may be used for repair. A piece of thin copper foil can be glued to the circuit board and soldered to the appropriate circuit trace. (Gold foil would be better as it will not corrode but might be just a tad pricey for a $10 remote!) Worn conductive material on rubber buttons: ------------------------------------------ Compare the bottoms of frequently used keys with those that are rarely pushed. If you can see the rubber through the conductive material after cleaning, the pad is likely worn to the point of being non-functional. This may be repaired with conductive Epoxy or other similar conductive paint or ink. A sliver of aluminum foil can sometimes be glued to the rubber surface. 3M makes EMI/RFI foil shielding tape, type 1181, that should work very well for this. is 20-2070. Not cheap but 400 contacts covers quite a few typical remotes. Note: I do not know whether it is easy to mix only enough material for just 1 or 2 contacts - it would be worth confirming that this is possible before ordering. Or else, invite a few dozen friends (and their flakey keypads) over for a remote repair party :-). There is also a material called 'resistive coating' or something like that that goes on like paint. It may be available from an electronics distributor. Or, if you are friendly with your local repair shop, they may be willing to spare a few drops. Occasionally, the conductive material is not actually worn off entirely only on the surface and there may still be some beneath surface. Light sanding may help. Unfortunately, there is no single best solution since the material used for the conductive rubber pads in remotes is not all the same. ********************************************************************** This message and its attachments may contain legally privileged or confidential information. If you are not the intended recipient, you must not disclose or use the information contained in it. If you have received this e-mail in error, please notify the sender immediately by return e-mail and delete the e-mail. Any content of this message and its attachments which does not relate to the official business of Eraring Energy must be taken not to have been sent or endorsed by Eraring Energy. 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