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HEQ5 pro high pitch noise


Carl Johan N
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Hello! I just got myself a second-hand HEQ5, sadly it is making a very annoying high pitch sound that is basically constant from startup. The noise is there whether the mount is idle or slewing, but is hard to pick out from the other noises when moving. When the mount is sitting still but turned on (ie not tracking or slewing) It's very annoying. It should be emphasized that this is not the movement sound or anything like that, it's much higher pitch (my mom can't hear it).

I've browsed these forums and it has been mentioned before, see for instance here:

https://stargazerslounge.com/topic/146665-is-it-usual-for-heq5-pro-to-hiss-when-idle/

But it was never 100% clear to me whether this is a general issue with the mount that some can hear and others can't, or if it's an actual fault with my mount.

Kind regards,

Carl Johan

(I've heard it's possibly the micro-stepping driver?)

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2 hours ago, Carl Johan N said:

Hello! I just got myself a second-hand HEQ5, sadly it is making a very annoying high pitch sound that is basically constant from startup. The noise is there whether the mount is idle or slewing, but is hard to pick out from the other noises when moving. When the mount is sitting still but turned on (ie not tracking or slewing) It's very annoying. It should be emphasized that this is not the movement sound or anything like that, it's much higher pitch (my mom can't hear it).

I've browsed these forums and it has been mentioned before, see for instance here:

https://stargazerslounge.com/topic/146665-is-it-usual-for-heq5-pro-to-hiss-when-idle/

But it was never 100% clear to me whether this is a general issue with the mount that some can hear and others can't, or if it's an actual fault with my mount.

Kind regards,

Carl Johan

(I've heard it's possibly the micro-stepping driver?)

Hej Carl Johan,

As soon as the mount is powered on (even without tracking), the stepper motors will take some electric current that will hold their positions fixed. That current is PWM (frequency) regulated, which can generate sound. I guess it comes from the motor coils.

My mount was just beside me when I read this so I recorded the power up sequence:

Audio recording 2018-09-08 16-46-51.wav

First klick is power on, after a few seconds the beep (and also the "klonk" when the stepper motors are powered up) then you can hear the high pitch sound. My phone was lying close to the mount during recording, and my ears need to be less than 50 cm from the mount to be able to detect any sound. And that is in a very quiet room. You may have a stepper motor that has a small manufacturing defect. Try disconnecting one stepper and listen if they are different.

Ragnar

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What are you powering the mount with? If the supply is not correct, I.e. In quality, it can damage the mount electrics. I had a power supply years ago for an electronic item that was poor quality. It's smoothing was poor and it produced a sceeching sound. I was too late disconnecting and it blew the electronics. 

So I would suggest checking the voltage under load. If it is too low red led flashes on the mount, off too high also a problem. Try another supply if possible and see if the sound stops.

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Re operating voltage for the HEQ5/ NEQ6 mounts. I've been using a 120W voltage converter (12v to 15v) on my mounts for the past ten years. Works well for me.....But I don't get any high pitched noises from my mounts......

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19 minutes ago, Carl Johan N said:

Thanks for the replies guys, I'll check the voltage and rummage around a bit to look for the source of the noise. In what range should the voltage be? (idle and load)

 

The recommended voltage range for the psu is 11 - 15v  and should be capable of supplying 2 amps minimum. The psu should be of the regulated type so the voltage won't alter whether the mount is under load or nor.

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The 11 volts is what is mentioned in the literature but is really far to low in practice. I would aim for never less than 12.5 volts if possible. Too low a voltage causes the mount to try to take more current and can cause circuits to blow. I.e. Volts xAmps= power. So low volts means higher current. 

If you measure the voltage at the supply and it is a long supply lead with small csa internal wiring, then the voltage at the mount will be much lower due to the wiring resistance. (So measure at the mount). Good quality supply and hefty wiring is best. 

 

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10 hours ago, bottletopburly said:

Yes probably annoying for you being younger hence why your mum can’t hear it ,they make mosquito speakers and place them where crowds of youngsters congregate the high frequency drives them away , adults can’t hear it .

Maybe Skywatcher has added this mosquito (and youngster) repellent feature for free. Will have to check if I can upgrade mine...

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