carrier splt sometimes doesn't respond to remote.

Hoping some electronics gurus can help me out here.
I've got a carrier split (42NG250H) that sometimes doesn't respond to the the remote.
Its weird because while I was there before I did anything, the unit was responding to the remote. I turned the unit off to strip it down and powered it back up when I had the fascia off and testing it, the unit wouldn't respond to the remote, but the a/c ran fine on test mode.

While testing it and the remote not working, I was checking the voltage to the reciever, 5vdc on terminals 1 and 3, and I did measure the reciver outputting 0-1.8v every time I pressed a button on the remote, but the unit not responding to remote commands.
Then when I put the fascia back on so the window covered the reciever, it started working perfectly again.

But I got a call yesterday saying it stopped working.

It could be the remote playing up, but it definitely was outputting light visible to my digital camera the whole time, and there was no channel options on the remote, so it's not a wrong channel. New batteries and reseting the remote has been tried too.

Even when the remote was not working, it always put out irfrared, and the reciever always responding with voltage output.

So besides guesswork, replacing the only non tested part (main PCB), can any further testing be done on reciever/remote?

Two points of interest, but non conclusive are:
The customer said sometimes the unit turns it self on, but I didn't see anything wrong with the board or connectors, that could be the emergency/test switch was on.
When changing batteries, the remote didn't power up, the batteries were a little loose, but it seemed to come good and worked about 10 times while I was there once I got the display working. When the owner called they weren't complaining about no display on the remote screen.

Couple of things spring to mind.

Energy saving or compact fluoro lights also transmit infra red, and can quite often flood the reciever, possibly it only plays up when the lights are on?

Most systems will have a 0.01 uF capacitor hanging of the signal going back to the micro, these quite often go leaky, meaning if the system is turned on, it may work a couple of times, than goes short, and pulls the signal down.

Battereis in the remote you already suggested, if these are low, quite often they need time to recover, in other words they will transmit and work, then if you change a setting the battery is still low, and that 2nd command won't go...

Good luck.

Buy universal remote and see what is happening! I always have one or two in my wan.

hello ive found the same problem with some carrier remotes ive found that if i turn all the lights off in the room then it works fine stefs cruiser says the light impedance messes with the infared signal otherwise change that capacitor
declan

Yeah, I know about the lights interfereing, but it wasn't working while I was there during the day and the lights were off.
They had halogen lights though anyway, not flouro.

Might check the capacitor, as suggested, and nike123 has suggested before, and get a universal remote for future testing.
I stopped checking everything because i) it started working and I needed to move on to the next job, ii), the receiver always put out a voltage when I pressed a remote button and iii) because the owner said sometimes it turned itself on, so I thought if anything, it's the main board faulty. So I just told them if it plays up, you need a new main PCB as everything else seems OK.

Of course they aren't cheap and have to be ordered in from the eastern states, and really it could still be the remote or the receiver capacitor :(

hello isnt there a facilty for a wired controller if there is i would just fit that its better well sounds to me like a main board fault maybe a dry connection

Sometimes sun rays reflections could play with remote control receiver. Put blinds on windows when checking remote control receiver.
Also, by this description,

Quote:

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I turned the unit off to strip it down and powered it back up when I had the fascia off and testing it, the unit wouldn't respond to the remote, but the a/c ran fine on test mode.

While testing it and the remote not working, I was checking the voltage to the reciever, 5vdc on terminals 1 and 3, and I did measure the reciver outputting 0-1.8v every time I pressed a button on the remote, but the unit not responding to remote commands.
Then when I put the fascia back on so the window covered the reciever, it started working perfectly again.

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it is most likely that you got some bad solder connections or cracked PCB. I would resolder all pins , check for cracks on remote control receiver PCB and check firm insertion of connectors.

Ive had the same problem with carrier splits at one site were 5 units wouldnt respond to the remote. Unsure of model numbers but i did get new PC Boards and Remote Reciever for them and the units started responding.

I got a picture of the remote of the units i had troubles with. Might be the same style?

http://i35.photobucket.com/albums/d1...M/Image022.jpg

Yeah same ones rude.

It's looking more to me as a PCB fault, if I'm going to replace that, I might as well get a reciver PCB in case the reciever or capacitor is playing up.
I did give the PCB an inspection while I was cleaning out the unit, as this intermittant fault was reported to me before I cleaned out the drain and coil (as well as it turning itself on and off), but couldn;t find and bad solder joins or loose connectors.

edit: I had the remote pointing right at the reciever for the times I was measuring the reciever output voltage, and it wasn't working then either.
So it might be cracks in the PCB.

Hey there everyone!

maybe you can open the remote control and check for any kind of stains, sometimes if liquids or dust go to the remote controller card you will get no response on some functions or complete malfunction.

this happened to me with a unit that when you pushed the cool button it turned off, because of some coffee spilling near the remote...

good luck!!

That was a good idea, about the lights. Last year I encountered the same problem and gave up, but the other day the guy called me up to remind me of his problem, ty.