Eneloop/Panasonic BQ-CC63 charger - noisy PWM IC

[spleenharvester]

I've had this Eneloop charger from new, and it works fine but has always made a really irritating ticking sound roughly once per second when more than one battery was inserted. I found the noise to be coming from the OB5222AG PWM DIP-8 IC. I tried replacing it with an identical part - the problem persists but rather than a ticking, it now sounds like a squeal. The problem is there are no spec sheets for this IC anywhere and no information besides it being a PWM IC, so I have no idea what to replace it with. Any ideas? Or any other way I can quiet this thing? Board pics attached. Thanks

[stj]

chips dont make noises other than "crack" or "bang"

it's coming from a coil.
find which and cover it in wax or silicone
and it looks like it's full of shit caps - you even marked them for changing!

[CapLeaker]

Comes from that transformer next to it.

[redwire]

The IC is just in auto-restart, hiccuping. I'm concerned the new IC behaves differently, hopefully not a reject part.
Just recap it already. Three different makes, priced to the penny. You marked the shit caps on the primary side but what about the secondary side? Check the output rectifiers diodes as well.

[spleenharvester]

Cheers all!

If it's the transformer I guess I might be stuck then as it looks like a custom wind - I'll try the wax, what kind do I need? Is it just a case of peeling that label off and pouring it on?

I didn't actually mark the caps, looks like the factory did that for me lol. I'll recap it.

[redwire]

It's not the transformer. Putting flammable wax all over it is a bad idea.
First, suspect the capacitors are toast causing the IC to go unstable. Or a short/overload on the secondary puts the IC in hiccup mode where it will click click click.

[stj]

about the wax, you could use laq or epoxy, your just trying to stop the windings moving on the core
but yes, caps first may fix it.

[CapLeaker]

the noise comes from the transformer. stj and redwire gave you already good answers why the transformer can make the ticking sound. Bad caps in the primary or, bad caps / bad diodes or a short in the secondary.

[redwire]

Eneloop chargers will charge for a few seconds, then stop and do a check. Then they repeat- charge for a few seconds and stop. This might be the noise OP refers to, the load being switched on and off.
But the charger didn't use to do this, so something has aged.
This looks like maybe 2A total output, 8 cells so 250mA each it's still a wimp. What's a better charger, my other Eneloop one went in the garbage for chronically undercharging yet telling it all was good at 1.40V

[CapLeaker]

I've got like a half a dozen chargers from 2 cells up to 16 cell chargers. None of them make noises you are talking about during the “check”.

[redwire]

There's a few other people complaining about Panasonic Eneloop chargers making annoying noises. Even new ones. So the design might have a problem.