Testing A Remote Control Unit

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I have a Yamaha theater sound system, which has been used incredibly little over the past five years. It has the standard tuner/amplifier/woofer and a number of speakers, and of course a hand held remote control unit.

Recently when I went to use the remote control, it would not seem to work. Naturally, I assumed it was a power issue associated with depleted batteries. However, when I went to replace the batteries with a fresh set, no luck. A test of both sets of batteries found them to be well within the range that they should have powered the remote plenty sufficiently to make it work.

I then checked all the other "usual suspects". Blocked receptor on the tuner, manually powered the tuner off and on and even plugged and unplugged the tuner, and of course all of that indicated that the tuner and the rest of the system was working fine.

Since this remote has not be dropped, damaged, immersed in water or otherwise spindled, folded or mutilated, I'm not sure what to make of all this. I located a replacement remote online for $34 (very reasonable), but then I got to wondering if the infrared receiver in the tuner might be the problem - although there's no clear reason why that would be not functioning either.

I was wondering if anyone knew of anyway to somehow test the remote control, and somehow isolate the problem to that device - which my instincts tell me is the source of the problem. Other than the buttons which just activate a small diaphram underneath to close a circuit and emit an infrared signal, the remote of course has no moving parts. I popped the remote open, and with a tester I can see that the circuit board is getting power, but beyond that I can't tell where the "point of failure" really is. Any home testing suggestions for a reasonably competent shade tree eletronics mechanic?

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Type: Question • Score: 0 • Views: 1,157 • Replies: 8

[+3] - contrex - 10/10/2009You can't always see an infra red LED operating with the naked eye. The sensor in a digital camera is sensitive to infra red so if you switch a digital camera on and point it at the remote, if you...

View best answer, chosen by CDobyns

@CDobyns,

You can pick up a universal remote for about 10 bucks; see if you can get that to work on the system, if not, then at least you will have isolated the remote as the cause of the problem.

Cycloptichorn

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@CDobyns,

CDobyns wrote:

I was wondering if anyone knew of anyway to somehow test the remote control, and somehow isolate the problem to that device - which my instincts tell me is the source of the problem. Other than the buttons which just activate a small diaphram underneath to close a circuit and emit an infrared signal, the remote of course has no moving parts.

You should be able to see the IR light up when pressing a button. If it doesn't light up at all then it's not working.

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@Robert Gentel,

interesting as this just (moments ago) happened to me re t.v. remote and the ir light did come on but did not lower the sound, I opened the battery lid and simply jiggled the batteries and voila the remote worked. just bad contacts I guess. I did go ahead and change the batteries and it's still working, so much for the ir light.

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You can't always see an infra red LED operating with the naked eye. The sensor in a digital camera is sensitive to infra red so if you switch a digital camera on and point it at the remote, if you look at the image on the digital camera's screen, the LED on a working remote will appear to light up very visibly when a button is pressed. (Try it).

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@CDobyns,

Many remotes can control several things and there are selector buttons on the remote so that it knows what it is controlling. Make sure the remote is set to control the receiver. It might be set to control a TV or DVD player.

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@contrex,

I've noted that contrex has provided the correct answer. Not to say that going out and buying inexpensive universal remotes might not be the answer too, but the suggestion to use a digital camera proposed by contrex was clearly the best, no-cost solution. Winner, winner - chicken dinner.

Shortly after I posted this question I stumbled over the same answer on the eHow website, not surprisingly under How to Test a Remote Control Unit (http://www.ehow.com/how_5141104_test-remote-control.html).

And no, unfortunately for most remote units , the human eye cannot detect the infrared signal being transmitted by just "looking at the emitter", so using some sort of digital device is the only way to make this work.

So, what about my situation? My digital camera indicates that my remote unit is working, but emitting a signal that is too faint to be picked up by the receptor on the tuner, even when the remote is right up against the receptor. The batteries do not appear to be the problem, so I'm going to see if something else isn't wacky with the unit that is limiting the signal output. I'm thinking possibly a lack of full contact with the batteries, although that seems unlikely, since electricity will mostly flow fully, even through a bad connection. I'm wondering about another component on the board now. I'll take a further look, but I think we now know that the problem lies with the remote, so whether it's a future $10 (or $34) investment in a replacement remote unit, that option is virtually guaranteed to solve the problem. Thanks everyone.

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@CDobyns,

Although we successfully resolved the problem with a diagnostic tool on how to assess the functionality of the remote control unit itself, I thought it would helpful to follow-up with a posting on how the problem with the remote was ultimately resolved successfully.

When we last chatted, the digital camera solution had pinpointed that the remote control unit was the problem, and that a very weak infrared signal was being emitted. I revisted the batteries in the unit with a voltage tester and confirmed that all of the batteries that had been used were all well within the voltage specifications.

Then I disassembled the remote control unit, and only after I very closely examined the negative battery contact point on the remote unit, did I notice that the contact had a build up of something on it (corrosion, dirt, volcanic ash, peanut butter - or something). I removed the battery contact assembly and using a Dremel wire brush attachment, I removed all of the foreign substance build up on the contact.

I reassembled the remote control unit, inserted the batteries (the original batteries) and ran my test with the digital camera again - and voilá, good infrared signal. A test on the actual tuner confirmed that the remote is now working just fine.

I guess this just goes to prove that on most of these electronics, the most logical problem is usually the simple solution. It's a little like my dad used to tell me, "son, if the car won't start - 19 out of 20 times, it's the battery - even when it seems like it can't possibly be the battery. It's the battery". He was a pretty smart guy.

So, we didn't need the $34 new remote or the $10 universal remote. This time around we were able to go with the $0 solution, and those are my personal favorite. Thanks again everyone.

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@CDobyns,

That is the first thing I would look for. When a remote starts acting up, I generally slide off the battery cover and rotate the batteries by rolling them with my thumb, and jiggle them back and forth lengthwise so that the negative contact spring gets flexed; the rubbing at the contact points usually removes the thin layer of oxidation and gets me half a volt or so and a few more weeks of battery life.

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Testing A Remote Control Unit

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