high pitched whine after DSL modem recap

[relkin67]

I have a Speedstream 5100 dsl modem that I just replaced all the GLuxon caps with Nichicon HMs. Unfortunately, it now has a high pitched while that developed about an hour after plugging it in. It still works (I'm on this forum) but I'm worried something is very wrong. I checked all the joints & polarity and they look fine. Anything else I should check?

[gonzo0815]

Re: high pitched whine after DSL modem recap

High pitched whine is not necessarily a serious problem, if there is no other apparent failure.
In fact it is very common for any switching circuit working in voltage controlled mode and light load, which most of the simple step down converter actually do.

For an solution you cans soak the coils with car motor sealant spray, epoxy or anything else. Let it cure before using it again,

[Topcat]

Re: high pitched whine after DSL modem recap

Nichicon HM(M) caps?? You may have just gone from bad to worse. The HN and HM series are both known to be junk.

[kc8adu]

Re: high pitched whine after DSL modem recap

whats the datecodes on your hm's?
unless they are very new stock they are nfg!