No response from amplifier

[bakadave]

Hi,

I have an Onkyo A-8870 amplifier which I'm trying to control over the RI port. Being able to turn it on and off would cover most of the functionality that I need, however I've been completely unable to get any kind of response when sending codes from an Arduino to the amplfier.
When controlling the amp through the remote controller I also don't get the expcected signal "out" of the RI port. I get some kinf of a deformed signal but it does not look like the RI signal that the Arduino makse.
Also I had to use a resistor across the pins of the jack connector because otherwise all I got was noise coupled over from the mains input (precisely 50 Hz).

These are the oscillograms using different values of resistors across the two pins.
470R

1k

10k

Anybody has any ideas what I'm doing wrong? This is the oscillogram of the Arduino output (not connected) which looks perfectly fine:

[docbender]

Hi, I don't know this type of amplifier but with A-803 it works. RI has only unidirectional communication so you can't expect any data from amplifier. It only receives data. Wiring is really easy. Tip of jack is signal, housing is ground. Between signal and GND is about 20k resistance. You can check it to be sure your jack is connected correctly. Good luck with debugging 20. 5. 2022 15:38, 15:38, David Baka ***@***.***> napsal/a:

…

Hi, I have an Onkyo A-8870 amplifier which I'm trying to control over the RI port. Being able to turn it on and off would cover most of the functionality that I need, however I've been completely unable to get any kind of response when sending codes from an Arduino to the amplfier. When controlling the amp through the remote controller I also don't get the expcected signal "out" of the RI port. I had to use a resistor across the pins of the jack connector because otherwise all I got was noise coupled over from the mains input (precisely 50 Hz). These are the oscillograms using different values of resistors across the two pins. 470R  1k  10k  Anybody has any ideas what I'm doing wrong? This is the oscillogram of the Arduino output (not connected) which looks perfectly fine:  -- Reply to this email directly or view it on GitHub: #12 You are receiving this because you are subscribed to this thread. Message ID: ***@***.***>

[bakadave]

I'm about to give up. I've everything hooked up, I've run the test program multiple times, I've also measured back that there isn't some signal quality issues cropping up (I connected the scope to the second RI port instead of to the Arduino output). Looks like my RI port is inoperable. I'll have to make do with infrared.
I'll be bringing the amp over to a repair shop for some unrelated problems, as a last resort I will have them look at the wiring just in case there's something disconnected inside the case.
Thank you for the help in any case.

[bakadave]

Is it possible that the RI cable does not provide common ground and I need to ground the Arduino to the amp separately for it to work?

[BrianAker]

Is it possible that the RI cable does not provide common ground and I need to ground the Arduino to the amp separately for it to work?

The following might be of help to you:

According to Onkyo, for RI to work you need to have your Onkyo components connected by RCA even if you have them digitally connected. This is specifically brought up in the manual for the C-7030, as well as the DS-A4.