I took delivery of the same printer today and have the same issue - maddening. Am about to box it back up again and return it. Very poor from Xerox.
Good to know, thank you.
My own investigations had narrowed down the source to the PWBA LVPS (a.k.a. "the PSU"), which generates the +24vDC and +5VDC from the AC power source. This is located behind the plastic vent grille of the left side panel (towards the front of the unit). Four screws to gain access, six screws to remove (plus cables). Part no. is 105K31091 (LVPS PWBA 220V (SCC)). The 110V part is 105K31091.
Looking at pictures online there seem to be at least four low-tech inductors that are good candidates for generating coil whine. Many PSUs have those components splattered with encapsulating epoxy to reduce the mechanical vibrations that cause coil whine, but the examples of the board in the 6515 I can find don't have any of that. Maybe that's the cause of the noise, maybe it's that the AC/DC converter doesn't have enough headroom or is a primitive design, I don't know.
If Xerox want to send me a replacement I'll fit it myself.
Xerox engineer called me yesterday. It sounds like Xerox has big issues with these printers, the PSUs were changed to meet new low energy targets and now they all make this standby noise. They have designed a replacement PSU and will swap out under warranty but due to current conditions, the engineers are awaiting stock. I will wait for the replacement as really happy with the printer aside from this.
Also got the same issue, bought the printer last week, and noticed the sleep mode noise issue straight away. Reseller arranged a return and replacement arrived today. The replacement also suffers the issue. Xerox support not very helpful.
Just wanted to let know, that I'm in the same situation.
Recieved it yesterday, and after fiddling around and finally got it to working as I wanted, the noise cannot be ignored.
Here are my version numbers:
System - v65.50.61
Controller ROM - v1.57.3
IOT ROM: v1.1.0
IOT2 ROM: v4.11.0
ADF ROM: v42.0.0
Fax ROM: v104.8.0
Panel ROM: v91.6.11
Boot ROM: v11.1.216
Bought the same device, WC 6515 - mine's also brand new - and I'm suffering from the very same terrible sound...
By looking at this post (top result on google when searching for: xerox annoying sound sleep mode) - it sure looks that all of the complaints are from users that bought the device recently,
I'm almost sure that this is a faulty batch...
@xerox - what are we suppose to do?
My s/n: 3740213309
I took delivery of a brand new 6515DN today and have the same coil whine when in sleep mode (which is the vast majority of the time).
Please advise if these WC 6515 models can be repaired or returned for refund or repair under warranty based on the coil whine.
Controller ROM: 1.57.3
Same terrible noise with the WC 6515DNI in sleep mode. Bought the printer last week.
Same here as well - terrible noise
Brand new product received yesterday.
The retailer asked me to contact xerox customer service first. Now awaiting device registration before they speak with me.
Very unhappy with the product - seems like common issue recently.
Should have gone with HP - regret now!
Now I have to switch the printer off every time after use as keeping it on stand-by is unbearable due to noise.
Must be a problem with either MCU or LVPS connections