Chromegatrol humming, is this normal?

[jtrayers]

Hello all, I just purchased a second hand Chromegatrol and find that although it functions properly, it emits a fairly loud hum when the Expose or Print switches are thrown. I have not used a Chromegatrol before and wonder if the humming is normal. I have been using an old Omega timer that does not hum. Thanks for your help.

John Trayers

 

[Ian Grant]

Is that a stabilised transformer you can here humming ? If so that's not abnormal.

Ian

 

[argus]

Mine hums too, but my darkroom ventilation is even almost louder.

G

 

[Larry Bullis]

I worked with lots of them over the years. Some are louder than others.

Don't worry unless you smell smoke!

 

[Bob F.]

Might want to check that the bolts holding the transformer down are tight and any rubber vibration washers/spacers are intact but other than that, as said, large transformers tend to vibrate & hum when under heavy load.

Bob.

 

[Arvee]

Bob's correct and you might also want to check the bolts/screws that hold the transformer laminations together. Sometimes the hum will loosen this hardware but they are usually secured with Pliobond/varnish to prevent this from happening.

-Fred

 

[PVia]

Mine hums in Focus mode, and also when exposing the negative...pretty normal, AFAIK.

 

[jtrayers]

Thanks everyone for posting replies. The humming does not sound as if something is loose, just the transformer vibrating. I am glad to hear this is normal. I will listen for any change that indicates something has come loose inside. Although second hand the unit does not appear to have seen heavy use. It is the later model, all in black.

John Trayers

 

[PVia]

As long as you're hearing an electrical hum and not a rattle I would think you're OK.

If you're musically inclined, electrical hum sounds at B flat...usually one way to tell normal line hum from other noises.

 

[argus]

If you're musically inclined, electrical hum sounds at B flat...

I have a musical absolute pitch hearing (do you say that in English?) and this one sounds about a quarter tone higher ;-)

G

 

[Bob F.]

Ah, but it will depend on where in the world you happen to be: usually 50Hz or 60Hz... http://www.phy.mtu.edu/~suits/notefreqs.html

 

[PVia]

Argus...we call it perfect pitch here in the US.

Indeed, B flat is 58.27 hertz, so if you have 60 cycle AC, it will indeed be a little sharp. Wow, never guessed someone would pick up on that one ;-)

Just a funny little story...a friend of mine once worked with a singer who said he wanted to sing a particluar song in the key of "B, little b"...honest to God truth!

 

[argus]

Wow, never guessed someone would pick up on that one ;-)

Well, I used to be a professional musician once...

G