I am trying to make a Rotel RC-995 preamp listen to its remote control again. Using the camera in my smartphone I can see the remote itself is working. So as a next step I want to test and / or replace the IR sensor in the amp.
The sensor seems to be fed 5.7 V, or that is what I measured. This seems to be a bit too much. Or at least, I see that most IR sensors that Conrad sells have a V max of 5.5 V. I've tested the output of the sensor but that was ~ 4 V regardless whether I fed it with an IR signal (led from remote or heat) or not.
So I guess I should simply try to replace it. Will just any sensor do? Is the frequency spec I see mentioned (for example 36KHz) relevant? Should I be worried about the 5.7 V?
Thank you! René
The sensor seems to be fed 5.7 V, or that is what I measured. This seems to be a bit too much. Or at least, I see that most IR sensors that Conrad sells have a V max of 5.5 V. I've tested the output of the sensor but that was ~ 4 V regardless whether I fed it with an IR signal (led from remote or heat) or not.
So I guess I should simply try to replace it. Will just any sensor do? Is the frequency spec I see mentioned (for example 36KHz) relevant? Should I be worried about the 5.7 V?
Thank you! René
The best test is to use an oscilloscope on the IR receiver output and confirm the data can be seen.
Fwiw, most 'remote faults' do end up being the handset rather than the receiver. Have you tried other remotes to see if any change in level can be detected on the receiver?
I can't see the 5.7V being an issue at all tbh. If you are worried and replace the receiver then you could just add a series diode to lose 0.6V (add a small 47uF 16V cap as well for decoupling) but I think you have non problem there.
The 36k is the carrier centre frequency of the handset data and its best to get the correct receiver, otherwise the sensitivity will fall off.
Make 100% sure the receiver is faulty first though as faults are rare... not impossible... but rare.
Fwiw, most 'remote faults' do end up being the handset rather than the receiver. Have you tried other remotes to see if any change in level can be detected on the receiver?
I can't see the 5.7V being an issue at all tbh. If you are worried and replace the receiver then you could just add a series diode to lose 0.6V (add a small 47uF 16V cap as well for decoupling) but I think you have non problem there.
The 36k is the carrier centre frequency of the handset data and its best to get the correct receiver, otherwise the sensitivity will fall off.
Make 100% sure the receiver is faulty first though as faults are rare... not impossible... but rare.
That doesn't read very well... the receiver carrier frequency should match the handset carrier frequency.
Thanks. I did try an other remote (but not one for this preamp) but no change there.
I will check it using an oscilloscope.
Btw, the remote stopped working when the whole preamp refused to be turned on. I got the amp working again by replacing a molten fuse but from that day on I couldn't control it with the remote anymore.
I will check it using an oscilloscope.
Btw, the remote stopped working when the whole preamp refused to be turned on. I got the amp working again by replacing a molten fuse but from that day on I couldn't control it with the remote anymore.
If you have a scope then that is pretty definitive. Look for a 5 volt swing in the data on the output pin of the receiver.
If you set the time-base correctly then you should see this kind of thing:
RC-5 - Wikipedia
If you set the time-base correctly then you should see this kind of thing:
RC-5 - Wikipedia
Attachments
That's a bit suspect 🙂 Unless the blown fuse was caused directly by the IR receiver developing a short then its hard to see how the receiver could have coincidentally failed.
It might be worth you isolating the output pin of the receiver from whereever it goes (but be sure to add if needed a pullup/pulldown resistor as some receivers are 'open collector' outputs)
Interesting.