Celestron 114LCM won't switch on

[KarlosFandango]

I have the aforementioned telescope but not used it in several years. It's just been sat, quietly out of the way in a small cupboard (dry, dark, nothing amazing) but not stored in it's box as perhaps it could have been. Nonetheless, I went to take it out as a friend had asked me to take it to his for an evening's viewing pleasure. I tried the batteries I'd just bought (16xrechargables) but was unable to get any signs of life. Between myself and a friend who's somewhat more conversant with electricity than myself, we discovered so far that there's no signs anywhere of life from it - but we're not (as yet) sure whether it's a poor connection from the battery compartment or the switch. We do know the batteries are good. 

Any advice on narrowing down causes, please?

 

Edited October 28, 2020 by KarlosFandango
added link

[DaveL59]

have you run it on rechargeable batteries before? 

They only give 1.2v per battery compared to 1.5v for alkaline cells so may be just not enough voltage to get it to power up. Worth trying a mains adaptor if you have a suitable regulated one of correct voltage.

[KarlosFandango]

Hi Dave,

Yeah - from word go it's always ran on just 1.2 rechargables without issue (aside from draining super-quick, my work around was just to have a stack charged ready). I don't have a PSU ready to go, but will be buying a 12v but at this time am unsure precisely what sort I should get (AC/DC?) and don't wish to blow it up...

[DaveL59]

it'll be a 12V DC but get a regulated one rated higher Amps than the unit needs, saves having problems when slewing etc, but check the docs or their website for the correct spec.

Are the battery contacts clean and in good order?

Always possible a wire has come loose internally but that'd mean dismantling and so on.

[Cosmic Geoff]

8X 1.2v = 9.6v.  My Celestron mounts malfunction when fed with volts this low.  Should be 12v to 14v,  from a 12v lead-acid battery or a regulated 12v mains to DC power supply of adequate amperage (e.g. 2 amps or more).

[KarlosFandango]

OK thanks, both

 

In the manual for the device, it states I need a 12VDC750 mA (Tip Positive). I see on Amazon there's one with a reversible polarity, will I blow this up if I accidentally plug the tip in the wrong way? 

 

What about this one? I'm not sure which way this one has it's polarity though...

Kasstino Power Supply Adapter 12V AC 100-240V To DC 12V 2A 24W

Edited October 29, 2020 by KarlosFandango
added links

[DaveL59]

I'd avoid the type that have reversible polarity esp if that's achieved by fitting the tip in one or other orientation, too easy to refit incorrectly if it gets disconnected. Do you know the size of the plug required?

If it's a regular 5.5/2.1mm then a CCTV PSU would do just fine such as the one you linked. At 2A it'll more than handle the load when slewing fast etc and better to have lots of spare capacity than be running the PSU nearer to its limit. I have a 5A one for my SW SynScan mount when powered from mains or a LiPo car starter pack for when I can't and both work fine 🙂 

[Cornelius Varley]

56 minutes ago, KarlosFandango said:

In the manual for the device, it states I need a 12VDC750 mA (Tip Positive). I see on Amazon there's one with a reversible polarity, will I blow this up if I accidentally plug the tip in the wrong way? 

Yes you will probably blow something up. That psu only delivers 12v/0.5a so isn't suitable anyway.

[Cosmic Geoff]

You want to eliminate the power voltage as a possible issue, so using a cheap or inadequate supply that might blow up your mount is self-defeating.  Only fit one that is correctly rated and delivers +12v tip positive with a 5.5/2.1mm plug.  

+12v tip positive with a 5.5/2.1mm plug is a common configuration, but don't rely on it unless confirmed with the spec sheet or a test meter.

[Starwatcher2001]

According to the manual (first google hit here: https://escdn.nl/assets/lcm114-manual.pdf )

"The LCM can be powered by 8 user supplied AA size alkaline batteries or an optional 12V AC adapter. To install batteries into the LCM"

Even though you've been running it previously in rechargeables, before buying a separate PSU, I think I'd stick a new set of Alkalines in (maybe Duracell) and see if that brings it to life. As Cosmic Geoff said, rechargables deliver a lower voltage.

[Anne S]

If you do buy a mains supply I would suggest getting it from First Light Optics if you don't have an astronomy dealer near you. As to tip size it is 5.5/2.1, the same as most other brands such as Skywatcher. Don't use a Meade psu as they are the wrong size tip. I owned a Nexstar 8se for several years.

Incidentally, my battery compartment stopped working in the end. The soldering isn't good! I only used it to stop power cutting out when the mains connect disconnected. You will need to make sure the cable is wrapped around an arm to reduce the weight pulling on the connector,

[KarlosFandango]

On 29/10/2020 at 12:02, Starwatcher2001 said:

...stick a new set of Alkalines in (maybe Duracell) and see if that brings it to life. As Cosmic Geoff said, rechargables deliver a lower voltage.

I've tried this and it's a "no joy" scenario

On 29/10/2020 at 12:16, Anne S said:

I would suggest getting it from First Light Optics

Excellent - could you perhaps advise on a particular model of Power Supply? I've no idea what I'm looking for..

On 29/10/2020 at 12:16, Anne S said:

my battery compartment stopped working in the end. The soldering isn't good!

That's interesting to note. Thank you