UNI-T UTG962E sig gen. Rasping noise at switch on

[807]

 Sig gen noise.mp3 (126.73 kB - downloaded 93 times.)Does anyone else get a rasping noise when switching on their UTG962E? It doesn't do it every time, but around 50% of the time it does. I haven't opened it up, so don't know if it's coming from the piezo buzzer or the relays.

I've attached an audio file.

Sometimes it goes on for longer & sometimes just a few clicks.

[BillyO]

Yikes! 

That sound is not supposed to come from any sort of electronic device.

I would open it up just to see where the noise is coming from.  Don't worry about your warranty.  Since it's a UNI-T you don't really have a warranty.

[coromonadalix]

someking of hissing noise ??   psu section, anything  like switching frequency at startup ??

[807]

Yikes! 

That sound is not supposed to come from any sort of electronic device.

I would open it up just to see where the noise is coming from.  Don't worry about your warranty.  Since it's a UNI-T you don't really have a warranty.

yep. I will open it & try & find where the noise is coming from. Although I'm not sure if I will still be able to fault find it, as the most it goes on for is around 2 seconds. And it doesn't do it every time. 

I was just wondering if anyone else has the same problem. I've seen a few reviews & no one else has mentioned it. 

[807]

someking of hissing noise ??   psu section, anything  like switching frequency at startup ??

It's not a hissing noise, it's a rasping'farting kind of sound that gradually decreases in frequency.

The sig gen uses a seperate power supply that has a USB socket. The cable supplied is a USB to barrel lead.

I suppose it could be the PSU. I could try a different power supply for a few days to see how it goes.

[tpolecat]

Hi, just to add to this thread in case anyone else runs into the problem. I spoke to UNI-T and this instrument needs a full 2A or even a bit more (mine needs 2.2) to start up. If voltage droops during startup the relays can oscillate (hence the buzzing).

- rob

[807]

Hi, just to add to this thread in case anyone else runs into the problem. I spoke to UNI-T and this instrument needs a full 2A or even a bit more (mine needs 2.2) to start up. If voltage droops during startup the relays can oscillate (hence the buzzing).

- rob

Yep.

I thought I had replied to this thread ages ago, but obviously not.

In my case, I had added an extension cable to the power supply. It seems like the resistance of the extra length of cable was enough to drop the voltage and reduce the current, causing the relays to chatter.