My GW-M5610 does the same, it's the backlight technology.
Quite different from LED. I've got a keyboard with a backlight that has the same kind of material and that hums on a pretty high frequency as well.
Could be the electronic discharge (sounds like a cheap condensator to me).

 

That's the EL backlight. I think Casio, and I know Timex has mentioned it in their instructions for EL watches. Nothing to worry about. Maybe a plus, your hearing seems to be excellent

 

The problem goes away with age....your age, that is

 

That's just the Flux Capacitor warming up.

Perfectly normal and won't affect you unless...

You activate it while travelling at 88mph in a DeLorean with the date set incorrectly...

^^ tells the truth on Internet forums

So many watches, So little time...

 

Yes I noticed that, too, I bought this model recently. It's normal though, the instructions say it might emit a sound when using the light, it's vibration from the light panel. I can only hear it when I have it close to my ear though. My other G-shocks and Casio's with EL don't make any sound I can hear from the light, though, but my older Timex digital watches do the same thing.

 

WTH?!?! You guys got 20/20 hearing

 

I have a hearing impairment since born in both ears. Even with my hearing aids on I can't hear what you guys are describing. Although with my hearing aids I hearing a funny noise when I walk into building with lots of smoke detectors.

Sent from my SM-G955U using Tapatalk

 

EL, depending on the chemistry (likely zinc sulphide) needs at least 60 V AC (and possibly up to 600V AC) to activate the light, so an oscillating step up circuit is employed. You are hearing the transformer, and it is quite normal.

actual transformer, image borrowed from internet

 

It’s problem I’ve heard about before and as best as I can tell it’s nothing to be alarmed about.

 

Same thing even for Omega Speedmaster X-33. There is an audible EL noise.

 

Ummm... they brought the DW-5900 back? I just checked eBay and there's all kinds of variants, including an all black DW-5900BB.

So what's the deal? Did they do a full retro and include all the functions of the original watch, with the addition of a back light?

 

The reissue version is missing some features of the original version, for example the analog clock in the left eye, the 24 hr stopwatch (now 60 mins), the flash alert and the auto repeat countdown timer, but now it has a light and a world time mode. See this thread for more details.

https://www.watchuseek.com/f17/dw-5900-reissue-4791987-2.html

In any event, the new one looks really cool. I find it quite comfortable to wear. The strap is more flexible than most G-Shock straps, though not of GW-5000 quality. Plus it removes the wrist gap of the DW-6900, on my wrist at least. My sample happens to be particularly accurate -- fast less than 0.5 second per week.

 

Unfortunately no. A new module with different functions.

 

Also a Timex of mine does...it is an Ironman Triathlon serie and when I press light button I can hear that huming noise. Altough didn't recall I've ever heard anything such this on a GS of mine.

 

Thanks guys. Man, I don't know what the heck is wrong with the forum search feature. I searched on DW5900.... and it apparently missed all the topics with DW-5900. When you search with a dash like DW-5900, it looks for anything with "DW" or "5900" and you get many hits that are meaningless.

Well, I have to say that there's one thing that always kind of tugged on me about the DW-5300, and that's those black glossy round pips on the bezel at the 4 corners. There's only two on the DW-5900, but they're larger. Very neat look about it, so retro. I may have to get me one of these, even though I'd pretty much swore I'd not buy another watch and just try to reduce the collection by 50% in 2019! ;-)

 

I usually search the forum with Google, for example: site:forums.watchuseek.com/f17 DW-5900