NAD C316 BEE Bad channel can it be the relay?

[Squidge69]

Good day everyone, this is my first post here so hoping that some more knowledgeable person knows a little more than I do.

I have a NAD C316 BEE. One of the speaker channels is super crackly.

I have plugged my headphones into the system and both channels are working fine. This led me to believe that it is probably the relay that has broken being the last thing between the headphones and the speakers. Maybe I am wrong?

I have tried tapping the relay lightly but to no avail.

IF it is the relay I can probably change it myself as I have had a little experience with renovating a 1960's B&O Beogram 1200 and plenty of soldering there.

I have attacehd an image of the relay. Would someone be able to:

1. tell me if it could be somehting else other than the relay?
2. If it sounds like the relay, (happy to change as they are cheap) but point me to an appropriate replacement, there are so many variations out there. I have managed to find similar ones, same Vdc, 8A etc but then all the talk of pins got mea little confused.

Im based in Sweden so any European online store would work well.

Thanks in advance for all your help.

Matt

 

[chrisng]

I also think it is a bad relay contacts, which can be confirmed by shorting the contacts.
Google JQX115F24VDC for replacement. If you can only find an 8-pin DPDT relay, cut off the "NC" pins to fit into the PCB.

 

[Squidge69]

Hi there
Thanks for the quick response. And good to hear you think it could be the same thing. Could you tell me how to short the contacts? Is it a simple thing to do?

Ill do a search for the part, So many variants out there, I jsut needed to be sure,

Thanks again

 

[chrisng]

You can solder short wires to the relay contacts to short out its contacts. Be sure to plug in a pair of headphones before turning the amplifier on and off, otherwise you'll hear a loud popping sound coming from the speakers.

 

[Squidge69]

Fantastic thanks. Ill give that a whirl.

 

[Squidge69]

Hi Chris again, with regards to cutting the two NC pins. And also with regards to the Relay, if I do that and then say I have got the wrong part and soldered it in, could it damage anything else on the board? Or will it just not work.

 

[chrisng]

Can you post a link, photo or the part number of the relay that you going to use for replacement?

 

[chrisng]

Im based in Sweden so any European online store would work well.

I found a relay PR21-24V-400-2A from Digikey Sweden should be a drop in replacement of JQX115F24VDC.
https://www.digikey.se/sv/products/detail/cui-devices/PR21-24V-400-2A

 

[Squidge69]

Hi there Chrisng

Thanks so much for searching that out. Very kind of you. With the one you found, am I correct in thinking that as its a 2 FROM A it has the correct amount of pins?



I also had a reply from another company suggesting these parts, but they said they would work if I was willing to modify the unit...

https://www.mouser.se/c/electromech...X3*MTcwNjc3NDI3Mi4xLjAuMTcwNjc3NDI3My4wLjAuMA..

 

[chrisng]

am I correct in thinking that as its a 2 FROM A it has the correct amount of pins?

Yes.

I also had a reply from another company suggesting these parts, but they said they would work if I was willing to modify the unit...

I believe those relays Mouser suggested should work, and you can measure the relay pin distances if that agrees with the datasheet.

 

[Squidge69]

Thats fantastic thanks for all your help. It seems a waste to throw away a perfectly good amp for the sake of a part costing a few dollars.

Ill make the order today and hope it all works out which I am sure it will do.
Once again thanks for your time and input. Wishing you a great weekend.

All the best

 

[Squidge69]

Hi there, so then, just a little update. I ordered the part from the US, installed it and I am still recieving lots of distortion from the right channel. the left channel works great so I am thinking that I have installed the part correctly and that the part works. But also leads me to believe that the problem wasnt the relay in the first place. But good to check these things anyway.

Just to recap, I can hear both channels clearly through my headphones. Hence leading me to the relay. If it isnt the relay could there be anything else that is causing the distortion?. Could it be the actual Right challel binding post itself?

Thanks guys

 

[Squidge69]

Oh one more thing to add. I cranked up the volume and all the sound just stopped. So I turned the amp off an on again and it came back, not sure if that helps?

 

[Squidge69]

Hmm, update, so i listened again through my headphones, with more detail this time, seems that I AM getting some distortion through the RIGHT channel on those as well. I couldnt here it at first but became apparent after listening to a house track

 

[chrisng]

Oh one more thing to add. I cranked up the volume and all the sound just stopped.

Check and clean the headphones jack switch contacts with Deocit, see if the problem goes away.

 

[BSST]

I'm suspicious of a problem in the right channel, especially since the amp went into protection mode.

I'd check the DC output voltage as a first step.

I've attached a service manual.

Good luck!

 

[Squidge69]

Hi there, thanks for the advice BSST, it was a little strange. Ill check that out.

@chrisng could that be causing the distortion in the speaker as well, or would that just be for the headphones. The problem is still there with teh speaker channel.

 

[oggioffshore]

Is there a tone defeat switch?
Those can make noise.
Some nad has impedance and a bridge swith on the back panel.
Should be cleaned and operated a few times....

 

[chrisng]

The headphones jack need to switch the relay coil 24VDC! It will damage the contacts over time if plug/unplug the headphones while the amp is power on.

 

[jitter]

Coil data says it's 1440 Ω so at 35 V (not 24 V) that's 24 mA of current to be switched by the headphone jack switch. I don't see how that could damage it. And there's a 1N4148 across the coil to suppres voltage spikes.
Edit: I just noticed there's also 510 Ω in series with the coil making the current closer to 18 mA.