Checking Your IR Remote and Replacing Your IR LED in the Roboquad

Wait! Don't throw your batteries away in your remote until you do this check! If this check doesn't work, the problem may be your IR LED.

If you didn't see that in your digital camera, then it just might be the IR LED, a transistor, or the CPU. Follow these simple tests, and we'll go from there.

First, we are working on the Roboquad Remote.

Step 1 - Make sure you have tried new batteries and that the batteries are seated well - then retry the steps in the video. If it is still not working, then proceed to Step 2.

Step 2 - Open the remote. Then, remove the batteries to access the 2 hidden screws. You will be removing 6 of them - 2 are on the top, 2 are in the battery compartment, and 2 are on the bottom.

Once this is done, then it's time to crack it open. You might have to pry it open, as some glue might have spread on the case. Don't worry: you won't break it as long as the screws are out. When you open it up, it should look like this:

Now, let's check the LED to see if we are getting anything to it. In the photo below, you will see 3 pad in a sideways triangle, and it's located to the left of the blue component: "a 4Mhz crystal." The one you want is the one on the far left, which is in front of Q1's collector. Find the Black battery line and make note of where it is connected to the battery housing. Now, get out your meter and put the setting to 20v DC (or auto DC) depending on what kind of meter you have. Place the batteries inside the housing; make sure to remember where the black wire was connected. Place your black ground lead from your meter in between the battery and spring. Place the red lead from the meter on the test pad in front; For the Q1's collector, you should read almost 0V. Now, press a button, and the stop button and it should read about 0.35v or so - and then back to 0V. If this test works, then Q1 is working and the CPU is working. The IR LED is dead and should be replaced.

If that did not work, then what could be the problem? It could be a bad transistor or CPU - let's find out. First, we are going to test the CPU. Find the pad that says TEST; it is under the CPU and has a black dot on it. Still with the ground in place, put your meter on the bottom test pad. You should get a 3.?? and 4.??, which will flip back and forth. Go ahead and press a button. It will now read 0V and stay that way for about 1 second. Then, it will return to its normal state changing voltage. If this did not work, then you may have a bad 4.0mHz crystal or a bad CPU chip.

Next, we should test the crystal. Place your red lead on the left leg for the blue crystal; you should get around 1.23V. On the right leg, you should get from 0.1? to 0.2? volts. If this doesn't check out, your crystal needs replacing. Now, check the other pads of the triangle - the top pad should read 4.5v, and the bottom pad should also read 4.5v. It will have those readings until you press the stop button - if you do so, it should drop to around 4.4v and then back up. if you don't get these readings, then the transistor is bad and needs replacing. If everything here is a-ok, then the IR LED is bad and will need replacing.

To remove the PCB board, remove the batteries and you will again have to remove 6 screws: 2 on top, 2 in the middle, and 2 on the bottom. Remove the board from the housing, and you will then have to remove the LED. I use a solder sucker iron from Radio Shack; you may use solder braid if you choose.

Make sure that when you reinstall the new LED, that you put it in correctly: the flat spot of the LED is to the left for the remote. The picture is on the PCB in case you forget. Screw the remote PCB back in, and do the first check again. If you don't see the LED blink, then you may have a bad solder joint. Make sure that you solder the LED from the top side. If you see it, reassemble the remote in reverse order.

I hope that you enjoyed this article and please keep coming back to see what else is new. Also, you can feel free to leave me a message or a comment, and I'll try to help out as much as I can.

Until then, GWJax

Comments

milw's picture

Just curious GWJax, did you actually have a dead IR LED? I've never had that happen before (but I do have a 360 controller that keeps shutting down even with good batteries!)

-scott 

GWJax's picture

Yes My IR LED did short out. I had no IR signal emitting from this remote in the article so I had to hack into it and I found that the IR LED was bad after checking all other components, I made the article for those who don't have a scope to check it so the next best thing was to use the digital meter. On getting the correct adjustment to match the IR freq. you would need a Oscope to do this. but many people do not have or do not understand what they are looking at when using an oscope. I hope this article will help those that are having a problem with the remote. If anyone has any questions about their remote please PM me and I help out as much as I can. Thanks for your post.

As of your 360 controller that keeps shutting down, You might have a short componet in the remote that is triggering the auto shutoff command. I would look for any leaking caps. or a faulty transistor. Try taking a can of freeze it "you can pick up a can of it from Radio Shack" and spray the electronics down and retry the remote, If this gives you a longer turn on time then you most likley you have a transistor that is breaking down."an old TV repair trick" an no this will not short out your electronics. I think I have a 360 controller that I might be able to help you in this area and have you run a few checks. GWJax

robomomom's picture

Wow, I just read the roboquad remote repair. My question is this. I have a working roboquad, a working remote, but the led light at the top of the remote and the light on the top of roboquads head never light up. all the other lights on both units work. I desperately want to fix this. I bought it on ebay for my son for his birthday and it never responds to the remote so it does a few things and shuts down. He is so dissapointed. Do you think a mom with no mechanical skill can do this? I can't find a remote to purchase anywhere. (besides, i can't afford it.) Are there people who do this for a living? Someone I could send it to for fairly cheap? thanks. this is a great site!

GWJax's picture

robomomom said:
Wow, I just read the roboquad remote repair. My question is this. I have a working roboquad, a working remote, but the led light at the top of the remote and the light on the top of roboquads head never light up. all the other lights on both units work. I desperately want to fix this. I bought it on ebay for my son for his birthday and it never responds to the remote so it does a few things and shuts down. He is so dissapointed. Do you think a mom with no mechanical skill can do this? I can't find a remote to purchase anywhere. (besides, i can't afford it.) Are there people who do this for a living? Someone I could send it to for fairly cheap? thanks. this is a great site!

I just sent you a PM.. Also the button on the top of the head is a RX reciever and will not light up because it is looking for the IR data stream from the remote. The LED on the remote in front of it is an IR LED and can be viewed by using a digital camera, camera phone, web cam, ect after a button is pressed. From the sounds of it it may just be the remote that is bad. I had a few people that to replace the 4mhz 3 pin resisnator crystal to fix there remote so that just cost them around 3-5 dollars for that part.

Jax

a roboboa owner's picture

remember that some cameras have ir filters to block the ir u may need to use a camera that dosn't like spykee's

Atma's picture

An infra red remote which I pry open had bad battery contacts. The battery had leaked. Cleaning the battery contacts did not help.
The motherboard looked ok except the capacitor on the power line had a greenish residue at the negative leg of the capacitor. I have re-soldered the battery contacts and the capacitor again but still the remote refuses to emit the light.

Just wondering if we can change infra red LED between the remote controls. Or are the infra red LED specific to a remote.
Any tips or pointers would be greatly appreciated.

-Atma

GWJax's picture

Atma said: An infra red remote which I pry open had bad battery contacts. The battery had leaked. Cleaning the battery contacts did not help. The motherboard looked ok except the capacitor on the power line had a greenish residue at the negative leg of the capacitor. I have re-soldered the battery contacts and the capacitor again but still the remote refuses to emit the light. Just wondering if we can change infra red LED between the remote controls. Or are the infra red LED specific to a remote. Any tips or pointers would be greatly appreciated. -Atma

Yes you can use the IR-LED from another remote. What type of remote is having a problem that you are working on? Maybe I can help you a little bit more in repairing it if I have that same remote.

 

Jax

Atma's picture

Many Thanks Jax, for your reply.

Its a TV remote for Sharp LCD TV G1663CESA.
I have read your article several times. Tested the voltage
at various points.

I am not sure how to check the IC (D64A 823 705K) which produces the freq. I guess the problem could be the crystal or the IC.

Any tips on what and to do next will be appreciated.
The remote is less than 2 years old and hardly used.

GWJax's picture

Atma said: Many Thanks Jax, for your reply. Its a TV remote for Sharp LCD TV G1663CESA. I have read your article several times. Tested the voltage at various points. I am not sure how to check the IC (D64A 823 705K) which produces the freq. I guess the problem could be the crystal or the IC. Any tips on what and to do next will be appreciated. The remote is less than 2 years old and hardly used.

Atma, Can you take a few close up Pictures of the circuit board for me and also a good close up snap shot of the Cap that had come corosionon it please.

Also are you sure that you are not getting any IR for the LED when viewing from a web cam or other digital camera? I assume you swapped out the LED already and made sure that the poles are correct for it when resoldered back in-place? Ans also did you not get any voltage to that IR-LED?

The photos would help me out quite a bit if you can post them including the solder side as well as the top side.

Jax

Atma's picture

Jax,

As requested photos of the remote for your perusal and comments.

Also take note the negative terminal of the capacitor was greenish.

I have scratched the soldered contacts. Test for continuity are good.

Thank you.

Atma

Capacitor

Capacitor 2

 

 

lamb 1's picture

I followed your advice to check the remote IR and found it did not show up in the digital camera( tried 2 different cams) when opened the circuit board in the remote was different from your illustration (see pic) no "crystal" no test spot for the chip can you Help??

lamb 1's picture

top of  remote  boardd