Onkyo TX-NR646 short IR range

[tibimakai]

I have picked this receiver up and after repairing it, I thought that I'm done with it.
After putting it all back together and tried using it, the remote would not work.
Replaced the batteries in the remote, reset the remote and the receiver. Updated the firmware also. No change.
I have tried from a short distance and it is working from a couple of inches.
I have took it apart and without the front cover, works up to a foot.
It is a 3 pin type IR LED and it seems like, it has the right voltages. +3.3V, GND, 3.25V signal. The signal drops, when I hit a button on the remote.
I have compared it, with a 636 receiver and that one, does the same thing.
What could be the problem?
IR LED part # IRM-3638M3S28

[redwire]

Re: Onkyo TX-NR646 short IR range

If you have compact florescent, LED lighting, their flicker can upset the IR receiver. Try it in a dark room.

A bad ground to the shell of the Rx module, a bad Rx module, bad Vcc decoupling cap at the Rx module, could make it have poor signal to noise.
Small chance the remote control could be transmitting very weak IR. Check for a bent LED and bad decoupling cap in the remote.

[tibimakai]

Re: Onkyo TX-NR646 short IR range

I have tried it in the semi dark living room(in cabinet), then on the kitchen table disassembled, still the same.
The only difference is that, assembled the range is even worse.
The metal housing of the LED is all solidly soldered.
I have three remotes and they all work from the same distance.
I will have to check the capacitors. I will check the 3.3V with a scope.
Thanks for now, I will update as soon as I'm able to test it.

[ngvuanh]

Re: Onkyo TX-NR646 short IR range

You might have bad IR led too.

[tibimakai]

Re: Onkyo TX-NR646 short IR range

In the receiver?

[ngvuanh]

Re: Onkyo TX-NR646 short IR range

In the receiver?

Yes

[tibimakai]

Re: Onkyo TX-NR646 short IR range

I have replaced the LED from the 636 and it is working now.
I have placed an order, for a new one.