Buzzing charge feeling coming from my HEQ5 PRO mount

[PESKYWAABBIT]

Hi Guys,

I was using my scope last night following the Doris malarky.

I was sitting on the floor with the power jack connected up in my HEQ5 PRO trying to get polar alignment. The mount was not turned on (I can't see polaris with that super bright illuminated polar scope) but it was plugged in with power. The legs of the mount felt like it was buzzing up my arms, almost furry feeling. As I was putting my eyes close to the polar scope I could feel the charge coming from that too when I accidentally knocked it. It seems everything metal was giving off a charge. The moment I took the power jack out, it obviously stopped.

What could be at fault here?

The mount worked correctly through my session but just quite worried in the long term I will be damaging my long saved for mount. (I have never experienced this in my previous outings about 6 days prior).

The power to the unit is supplied by a basic DC to cigar car transformer. Is it worth replacing this component in the mix or maybe the Sky Watcher jack cable?

 

Any advice always is much appreciated 

[michaelmorris]

Sounds like an earth loop.  I've had this twice and both times is down to a faulty 230v cable.  On both occasions using a new mains the cable cured the problem.

 

[Cosmic Geoff]

I don't want to alarm you, but given the reports in the media of cheap Chinese-made devices catching fire, you should investigate, and discard any 'basic' product that might be causing a problem. Any plug, extension lead, etc could possibly be wrongly wired, making 'live' what is supposed to be safe. Your life could be in danger. Better be cautious than the subject of an obituary.  A test meter or neon screwdriver is useful in these situations.  Are you 100% certain that the wall socket was not wired by a cowboy? (It has happened...)

It is also possible that there is a small capacitative feed-through from the mains side to the DC output (which most likely is floating relative to earth) and that you can feel it. 

Though inconvenient and generally unnecessary, it would do no harm to you to earth the metal of the mount - and if that causes something to blow up, you've pinpointed the problem.

[Skipper Billy]

Personally - I would unplug it from the mains immediately !!!!!

Then try it with a 12 volt battery and see if the problem goes away. If it does its probably something to do with the mains transformer.

240v mains is not to be meddled with by people who are not entirely sure what they are doing !! It doesn't mix well with a damp environment and wet metal.

Mind you 12v deserves respect too - I have witnessed a man deglove his finger when his wedding ring started glowing as it shorted out a car battery.

 

[JemC]

Agree with Skipper Billy, unplug it and have it checked out,

1 hour ago, PESKYWAABBIT said:

The mount was not turned on (I can't see polaris with that super bright illuminated polar scope)

There is a setting in the handset that allows you to turn down the brightness of the polar scope, i think if you go into the Utilities button and scroll through it is called polar scope LED, 

[Mr Spock]

My EQ-6 does this. As far as I'm aware the behaviour is quite normal and no cause for concern.

[Chris]

As I sold you the mount, I just want to re-iterate that the 12v camping adaptor from Halfords a chucked in for free was a temp stop gap, it isn't a regulated supply therefore whether this bahaviour is normal or not I would recommend a proper regulated supply. 

Hope the mount is ok other than the buzzing?

[swag72]

I have always had some form of 'buzzing' on all of my astro equipment.... I've always put it down to our dodgy Spanish electrics. My husband has cured the issue buy putting a BIG earth wire direct from the pier to the floor of the obs.... Hardly get any issues now.

[Cosmic Geoff]

28 minutes ago, Mr Spock said:

 

My EQ-6 does this. As far as I'm aware the behaviour is quite normal and no cause for concern.

 

I don't agree. As a former engineer, I don't think this is acceptable. The thread quoted my michaelmorris makes interesting reading - it seems the issue is not unknown. However I did not have any issues when using a 12v switch-mode with a SLT mount out of doors. And just now, I looked for voltage between the output of a powered-up laptop supply and earth, and likewise a 12v plug-top PSU, and could not detect a thing.

My advice remains the same - check for lethal hazards, substitute the suspect mains PSU and consider earthing the mount metal.

[Davey-T]

Better safe than sorry, there are some scary videos on YT of dodgy Chinese electrics 

Dave

[Cornelius Varley]

11 minutes ago, Chris Lock said:

As I sold you the mount, I just want to re-iterate that the 12v camping adaptor from Halfords a chucked in for free was a temp stop gap, it isn't a regulated supply therefore whether this bahaviour is normal or not I would recommend a proper regulated supply. 

Hope the mount is ok other than the buzzing?

That type of psu shouldn't be used with a mount, full stop. Non regulated PSUs can cause erratic behavior or even stop the mount from working.

[Chris]

1 minute ago, Cornelius Varley said:

That type of psu shouldn't be used with a mount, full stop. Non regulated PSUs can cause erratic behavior or even stop the mount from working.

Agreed Peter, I'm regretting throwing it in now. I did say it was not a permanent solution and he needed to get a regulated supply.

It's a 12v 5Amp supply, so I think it would only drop volts in cold weather not blow any thing up. Definitely a chance of erratic behavior if the volts drop too much. I've seen this on one of my prior NEQ6's!

[PESKYWAABBIT]

Okay guys cheers for the advice. I will replace it ASAP!

3 hours ago, Chris Lock said:

As I sold you the mount, I just want to re-iterate that the 12v camping adaptor from Halfords a chucked in for free was a temp stop gap, it isn't a regulated supply therefore whether this bahaviour is normal or not I would recommend a proper regulated supply. 

Hope the mount is ok other than the buzzing?

No worries Chris I forgot it wasn't regulated. Need to get myself a new one then.

Other than that, the mount is awesome mate and works a treat!

Anyone got any suggestions as what would be adequate power supplies?

Cheers!

[laser_jock99]

Both my EQ6's have done this - even with the recomended MAPLIN 12V 7A regulated power supply.

[Chris]

https://www.firstlightoptics.com/power-accessories/baader-outdoor-telescope-power-supply-12v-5a.html

This doesn't specifically say regulated? but it does say it accounts for voltage drop during cold temp use so I guess it is.

Plus Baader make pretty much everything well!  

And it's rated for outdoor use unlike the one you have!

 

P.s I'm glad you're enjoying the mount other than the buzzing mate  

[Alien 13]

Earth the mount at source easily done with a metal rod put in the ground, I worked in aerospace many years and even medical power supplies when tested had 70 Volts on the ground connection same as EVERY other switched power supply that wasn't earthed and very few have that option. Its almost as bad as the old valve TVs that had a floating metal chassis and hence an earth connection that that had 110 V on it and would give you a shock when plugging in the aerial.

A bit of a rant here but I feel ALL PSUs of this type including mobile phone chargers should be banned and its not the manufacturer but the design principles at fault.

Alan

 

[Cornelius Varley]

14 hours ago, Chris Lock said:

https://www.firstlightoptics.com/power-accessories/baader-outdoor-telescope-power-supply-12v-5a.html

This doesn't specifically say regulated? but it does say it accounts for voltage drop during cold temp use so I guess it is.

Plus Baader make pretty much everything well!  

And it's rated for outdoor use unlike the one you have!

 

P.s I'm glad you're enjoying the mount other than the buzzing mate  

The blurb for the PSU says "The Baader Planetarium Outdoor Power Supply 60W provides 5 Amps and 12,5 Volt continuous", which means it is regulated. Unregulated PSUs cannot provide a continuous stable supply. If the load (amps) increases in a unregulated psu the voltage drops and visa versa, voltage rises > amps drop. A regulated psu will always supply the same volts and amps.

[Waldemar]

This is a very common issue. Very often it is cured by changing the mains cable to your power supply. You won't get electrocuted, but it is not as it should be. Those are leak voltages, normally far below dangerous levels, but again a word of caution is in it's place.
It may even be caused by a USB connection. 

Anyway I hope you keep 'buzzing' around with your mount 

[Skipper Billy]

Get a leisure battery !!!!

http://www.countybattery.co.uk/caravan-boat/110ah-leisure-battery-enforcer-leisure-caravan-110r-web-only/?gclid=CNn14cjLrdICFW0R0wod6k0JFA

[PESKYWAABBIT]

What do you guys think to this one? The description doesn't specifically say outdoor use. But the spec implies it's safe outdoors under certain amounts of humidity and within temperature.

https://www.harrisontelescopes.co.uk/acatalog/Celestron_-_SkyWatcher_Compatible_12v_Mains_Power_Supply.html#SID=1667

 

 

[Cornelius Varley]

28 minutes ago, PESKYWAABBIT said:

What do you guys think to this one? The description doesn't specifically say outdoor use. But the spec implies it's safe outdoors under certain amounts of humidity and within temperature.

https://www.harrisontelescopes.co.uk/acatalog/Celestron_-_SkyWatcher_Compatible_12v_Mains_Power_Supply.html#SID=1667

 

 

That should be fine. I' used a similar PSU before replacing it with a maplin psu.

[PESKYWAABBIT]

14 minutes ago, Cornelius Varley said:

That should be fine. I' used a similar PSU before replacing it with a maplin psu.

Thanks for clarifying. The Baader power supply looks like it will work. But astronomy as we ALL know is pretty expensive and if there's a cheaper solution to the problem that works and is proven, I'm up for that! Cheers for all the help guys!

 

 

[Geoff Lister]

A slight "furry" feeling is common when touching metal connected to the low voltage output of a mains power supply. The power-brick/plug-top supplies often incorporate a low-capacitance, high-voltage, capacitor linking the input (230V a.c.) and output (12V d.c.) circuitry. If the product label on the supply shows a symbol of a concentric pair of squares, this indicates the "double insulated" isolation of the mains voltage, from earth return, and the output circuitry.

A very small leakage current will often give that "furry" feeling, particularly if the output connector, or anything metallic connected to it, is touched with the back of the hand (much more sensitive than fingertips).

However, if the supply has an earth connection, this may only be used to provide safety protection for the power supply metalwork and sometimes it is needed to meet the EMC requirements for electrical goods. If the supply uses a "kettle" style plug-in mains lead, or, smaller, "clover leaf" connector, it is worthwhile checking with another lead.

Regards,

Geoff

[michaelmorris]

5 hours ago, Waldemar said:

 Very often it is cured by changing the mains cable to your power supply.

That's what worked for me on both occasions.  One both occasions the problem ended up being sub-standard 230v external use rated power leads, not the power supply itself.

[Stub Mandrel]

SMPSUs are normally completely isolated from the mains and not earthed. That means it takes very little leakage to 'float' them to any voltage.

When all your kit is double insulated, it's very hard to create a route back to the earth wire of your extension lead, but if would suggest doing this if possible as it maximises your protection in the case of a fault. Earthing to a ground spike might get rid of the 'fizz' but won't give any extra protection if the mount or tripod becomes genuinely live.