[OT] IR remote repair

commandeered

Given any thought to roughing up the deposit with one of your wire brushes? Something with .030" heat treated wire running at high speed should do it.

Harold

My Commodore 32 used to have those conductive rubber pad switches on the keyboard. If I didn't use it for a while (which was usually the case as it was so old), it seemed like dust built up under the contacts and the keys wouldn't work. To fix the problem I took apart the keyboard and wiped the PCB using a rag dipped in methylated spirit. I think sometimes I wiped the rubber pads, too. This always worked for me.

Best wishes,

Chris

The brush to use would be a 15" knot-type but it might leave ferrous deposits on the PCB that would soon oxidize.

Funny man...

No problem. Pickle the board in sulfuric acid afterwards. It'll dissolve any traces of iron.

Funny man? Me?

Depends on how much you want your remote. CaiKote44 is what you need but it cost about $25 for 3.5g from CMH chemicals or Newark.

Hardly worth the trouble. A new universal remote can be found on sale for under $10. Bugs

Youbetcha! My time limit includes 10 minutes of attempted repair and 10 minutes of NG wisdom then it's off to the dollar store. Most things that are throw-always can be repaired in that 20 minutes, so it's worth the attempt as long as one doesn't become obsessive.

There are special eraser looking things for cleaning contacts and copper, but for most uses, a plain old red eraser will do the job. I doubt your switch contacts are copper anyway, most likely carbon deposits that are crudding over. That's my first trick, and when electronics repair was my job, that unsharpened pencil with the worn eraser wasn't for writing!

Try lightly sanding the conductive rubber buttons fine abrasive paper to expose some fresh material?

Jeff

I'd be a bit cautious using abrasive paper. I've screwed up some contacts by trying to clean them with emery paper in the past. If methylated spirit and a rag doesn't work, try one of those oil-impregnated fibre contact burnishing strips. Search online for "contact burnisher".

Best wishes,

Chris

I hear what you say Chris, and I wouldn't use abrasives on a metal contact because I've heard tell that particles of the abrasive can lodge in soft metal (like silver) contacts and act like little "insulated hold offs" which keep the metals from touching as well as they should.

However, we're talking conductive rubber (or some elastomer) here, and I don't think the same holds true there because of the soft nature of the material, plus you don't need milliohm contact resistance in those TV remotes and similar gadgets.

An oil impregnated strip is the *last* thing I'd use on that kind of contact, because I'm convinced the greenish guck you find inside the keyboards of TV remotes and other devices with "rubber buttons" is your own body's skin oil which migrates down through the rubber, and maybe also plasticisers which leach out, so I'd say oil of any kind is a no-no there.

Just my .02,

Jeff

Tom,

Stay from all the advice about using anything stronger than a pencil eraser,.. Actually I'd stay away from that too.

My usual techneque is to use isopropyl alcohol to clean the PCB, many times those PCB pads have a graphite like coating on the and the I.A. dosen't seem harm that.... Clean the keys with it also... it's been my experiance that it's the keys that go bad, I've had good luck cutting the keys from the keypad I don't use and replacing the bad key with it...

Dave

There's also a 2 part "rubber keypad repair kit" from chemtronics;

It's not so much the insulating particles I'm concerned about; it's the fact that the metal layer is really thin. I'd be concerned about destroying it completely. Really fine emery paper would probably be okay, but personally I wouldn't want to use coarser than 800 grit.

I take your point about oil accumulating muck, but these strips are only impregnated with a very small amount of oil. I think the idea is that the oil softens and dissolves the muck. Even if they don't solve the problem, I don't think oil impregnated strips will do any permanent damage.

Best wishes,

Chris

The zig-zag pattern of tracks they normally put on the printed circuit board is solid enough to take a gentle clean with an ink rubber. Preferably those old grey and white style ink and pencil rubbers (or eraser depending on which school you went to!).

The fine abrasive cleans off the copper track nicely and is gentle enough to use many times on the remote over the years.

The rubber pad that forms the buttons is easily cleaned with dish washing detergent and your fingers in the kitchen sink. Allow it to dry before putting it back together. If the little conductive bit has fallen off, then you can cut one from another old dead remote control and glue it in place with superglue (CA).

Hope this helps, Peter

Before the advent of cheap universal remotes, I did a fair amount of this. One of the problems is that the carbon buttons tend to be a little abrasive, I've seen remotes where the metal was entirely removed from the circuit board on the more heavily used buttons. This can be temporarily repaired with some metallic circuit board paint but it isn't a real fix. A lot depends on what the pattern is under the buttons. Some have a spot that has a split down the center, some have a double spiral. Obviously, the split spot will be easier to paint than a double spiral. They make a kit for repair of these, Chemtronics has it. Last retail I saw on it was like $25, which would get you a couple of universal remotes from wally world with change left over. When remotes were like $80 for a factory replacement, they were worth working on. For $10 or less, pick up a universal that glows in the dark... If the isopropyl alchohol doesn't work, bin the thing.

Stan