more and more cameras (including phones) are using IR lens filtering. I always check IR transmitters by checking the voltage drop across the IR diode.

By placing your voltmeter across the two pins of the diode you are measuring how much voltage is lost across it. If you measure 0V, the diode is a dead short (bad) if you read 12V or more, the diode is not conducting voltage (bad). You should typically see somewhere between .8V and 1.4V across the diode, if you do, it's safe to assume that the diode is producing light.

With that said ... IR diodes are very inexpensive so you may as well just replace it, especially if it's never been replaced before. http://www.mouser.com/Search/ProductDetail.aspx?qs=KIIz7VjqD7I4A%252bR7oPm1DQ%3d%3d

digital camera will accomplish what you're trying. Phones no worky

On my phone I have to use the front facing camera. The rear has the filter

Unless it's a very inexpensive digital camera, it will have an IR filter.

Some phones cannot detect IR spectrum light produced by optos and iPhones are one of them. The Samsung Android phones I have seem to work great as well as most digital cameras. The LED flashlight on the phone actually works pretty well for triggering the receiver.

This is very surprising as an LED has an extremely narrow wavelength, are you sure this phone is using an LED light? I don't know of any visible light LEDs that extend into the 880nm range.

LEDs

How inexpensive do you think?

I can't say for sure, I bought a super cheap Cannon camera that was under $100 to document restorations and it can see IR light just fine. The Cannon camera I have that was over $200 is not able to see the IR light because of lens filtering.

Why filter it? By filtering out IR light at the lens, the camera will produce sharper images with more vibrant and realistic color as compared with the human eye.

Yep. Galaxy Note 2. Turn the phone flash on and point it at the receiver in switch edge test mode. Have a $2 LED flashlight that works testing receivers as well.

I think people have become far too reliant on mobile phones - like it's the Swiss army knife and able to fix anything electronic.....WTF!

Use a multimeter as suggested earlier in this thread, it is far more accurate, reliable and made for the job. Even a cheap $10 one will do a better job that relying on a phone.

Keep the phone for making calls.

Whatever.

A camera on a phone is a great way to quickly check whether or not a transmitter is working. You're not going to be able to get a meter on an opto buried down on a ramp in a game very easily.

I do lots of repairs in location. Just three weeks ago I found which 2 trough transmitters on a Demolition man weren't working with the camera in my phone and replaced them. Even used the flash to check the receivers. Done. I'm not testing every diode with a meter. Takes too long. Sorry.

Using a phone camera is a quick and easy way to test optos, why wouldn't you use it, it's already in your pocket?

I was very disappointed to find that my brand new 6S+ couldn't see the opto lights. One reason why I don't use it as my main phone.

--
Rob Anthony
Pinball Classics
http://LockWhenLit.com
Quality Board Work - In Home Service
borygard at gmail dot com

While this is true, you also aren't going to get your camera inside the ball trough. I'm not knocking your camera, use whatever works best for you, everyone checks things the way it works best for them; but if the end goal is checking all the transmitters in the game in the least amount of time, the meter is going to win every time as you can actually check every transmitter in the game in under a minute by checking them all right at the driver board connector.

I'm not really sure why you would want to shine a light on the receivers to test them rather than using switch test and looking at them all at once, but again whatever works for you is what you should do.

Because the switch test only tests that BOTH transmitter AND receiver are working. It won't tell you which one isn't, right?

Been using an 8mm video camera way back in the days before cell phones. Works for me and I'm not changing.

I guess, I just figured you already checked the transmitter with your phone and if its not working you kinda already know what the problem is

Besides you specifically said you replaced the transmitters and then checked the receivers with your phone. I would think you would want to check them with the actual light from the transmitter rather than a light source that is likely 1000 times brighter that the IR transmitter.

Listen, I've obviously struck a nerve here and you are taking this way too personal, no one is asking or suggesting that you change the way you do things, and you can put a negative on me all day long for suggesting there are other ways to check these devices; but, for the other people in in this forum that are reading this thread, I would think that they would to have some other options for checking these devices especially for the ones that are impossible to check with a camera without taking things apart, or without having to buy another phone or camera.

I'm not sure if you tried cleaning them, but if either are dirty, it could cause you to not have enough light hitting the phototransistor for it to conduct. I'm not trying to bash the phone/light method here but its very possible to be able to see the light with your phone, and have it register a closure by hitting it with a bright light ... and it still not work because the phototransistor isn't getting enough light from the IR LED.

No it's cool. I tested the transmitters with the camera and saw two were out. Then checked the receivers with the flashlight and all worked. So I knew what to do at that point.

I understand meters are great and use one. But for checking optos, I use the phone. Sometimes it's something simple as a cracked solder joint on the board at the header or opto. I typically check that next because replacing a good opto just because they're cheap isn't the best policy.

Just don't want people to think it's wrong to use a camera. It's an alternative way to check. It was Homepin that struck a nerve saying his way is the only way and any other way is wrong.

That is incorrect. You mean that YOU assumed I was saying my way is the only way and that is not what I said.

My main comment was that people should use the right tool for the job and not rely on a phone because there are too many variables and the results can often be misleading.

I also think that the majority of pictures taken with phones are crap but that doesn't mean I think everyone should run out and buy a $1000 Canon!!

I think that it's just my "Australian way" that seems to rub some sensitive people the wrong way - so be it, I'm not changing.

I confirmed that my iPhone 6 rear camera doesn't show ir but the front facing camera does. I've used an older phone for this type of thing in the past. Good first pass troubleshooting.

To test triggering the optos you can use an incandescent flash light. If the light triggers them correctly them your issue is on the transmitter end. If not, it's on the receiver end