Orpington Astronomical Society

Astronomy => Technical => Topic started by: Fay on Apr 11, 2008, 16:07:09

Title: Thought I'd Blown the Mount up!!!
Post by: Fay on Apr 11, 2008, 16:07:09
I thought, I will go up the shed, as the batteries are up there, & test the GPUSB.

Attached correctly to the battery & suddenly the garage was filled with thick smoke. I thought it was either going to blow up or set fire. Good job I reached into the inferno & grabbed the cable out of the mount. The cable had burnt within 1' of the mount in seconds.

Seems it must be that the wires must be touching somewhere.
Frightened the life out of me. Have tested mount via mains & it seems ok.

Am now having alchoholic therapy!
Title: Re: Thought I'd Blown the Mount up!!!
Post by: mickw on Apr 11, 2008, 17:08:35
If the shed burns down you could build an observatory  :twisted:
Title: Re: Thought I'd Blown the Mount up!!!
Post by: Fay on Apr 11, 2008, 18:13:07
I would probably gone to that great observatory in the sky myself as well!!!!
Title: Re: Thought I'd Blown the Mount up!!!
Post by: Ian on Apr 11, 2008, 19:33:59
cool, you'd get a good view from up there :





Erm,  :oops:
Title: Re: Thought I'd Blown the Mount up!!!
Post by: MarkS on Apr 11, 2008, 19:39:15
Fay, that's terrible.  What a scary experience.  I'm glad everything seems O.K. though.

What size fuse do you have in the lead?  Why didn't it blow?
Title: Re: Thought I'd Blown the Mount up!!!
Post by: Fay on Apr 11, 2008, 19:58:50
That's funny you saying that, Mark. There was not one in there. It was only a cable with croc clips & the bit that goes in the mount. Where would the fuse go?

My son also asked about a fuse. 
Title: Re: Thought I'd Blown the Mount up!!!
Post by: Mike on Apr 11, 2008, 22:38:12
Fay you know that any pyrotechnics must be saved for Deep Sky Camp.
Title: Re: Thought I'd Blown the Mount up!!!
Post by: Fay on Apr 12, 2008, 08:12:58
Mike,

believe me, if anything had happened up the shed, you would have seen it from miles around!

My mounts legs are scorched!!!!!!
Title: Re: Thought I'd Blown the Mount up!!!
Post by: mickw on Apr 12, 2008, 08:24:07
Fuses...........................
I assume you are talking about the lead from battery to mount - croc clips one end, mount plug the other.
You want one of these, or similar
http://www.maplin.co.uk/Module.aspx?ModuleNo=20624&criteria=fuse%20holder&doy=12m4
And a pack of these - 6.3 amp or 10 amp - I think the HEQ5 uses 5 amp normal running and the purpose of the fuse is to stop things bad happening, like smoke and flames  :(
http://www.maplin.co.uk/Module.aspx?TabID=1&DOY=12m4&ModuleNo=462&criteria=

Cut one of the wires at the croc clip end, then fit fuse holder between cut ends, insert fuse and retire immediately  ;)

Also, depending on how much damage has been done, you might need one of these
http://www.maplin.co.uk/Search.aspx?criteria=HH60Q&DOY=12m4
Title: Re: Thought I'd Blown the Mount up!!!
Post by: Fay on Apr 12, 2008, 08:33:41
Mike,

really grateful for that info. I will get one, never knew about them, but obviously very important. I don't think the cable was man enough either. Is thickness of cable important? What thickness do you think I need?
Title: Re: Thought I'd Blown the Mount up!!!
Post by: Fay on Apr 12, 2008, 08:34:43
Sorry, I meant Mick!!!!!!!!! Keep getting names wrong, well I have just got up.
Title: Re: Thought I'd Blown the Mount up!!!
Post by: mickw on Apr 12, 2008, 09:54:42
That's OK Doris, easy mistake to make  :lol:
If you bought the lead already made up, the size should be OK.  Sounds like your problem was a short circuit, there's many cables that could survive being whacked across a fully charged battery - You can melt a screwdriver shoving it across a battery  :(
Never been much good at putting a name to cable sizes but tke a look at the cigarette lighter cable that came with the mount - something the same size or larger will do.
Also, virtually any flex from an old appliance - hair dryer, iron, radio should also be OK
If you have to buy it, this is plenty big enough (price is per metre) 6 or 10 amp
http://www.maplin.co.uk/Module.aspx?ModuleNo=20666&criteria=figure%208&doy=12m4
Let me know if you want help
Title: Re: Thought I'd Blown the Mount up!!!
Post by: Tony G on Apr 12, 2008, 12:28:06
Fay,

Sorry to here about the mount, but lucky for you as well that you caught it in time. I see Mick has been giving you links to Maplin's well just in case here is another.
http://www.maplin.co.uk/Search.aspx?criteria=fire%20extinguisher&source=15&SD=Y (http://www.maplin.co.uk/Search.aspx?criteria=fire%20extinguisher&source=15&SD=Y)

Every observatory/shed should have one. ;)

Tony G
Title: Re: Thought I'd Blown the Mount up!!!
Post by: Fay on Apr 12, 2008, 13:02:31
Mick you could have called me Bridgitte or anything but DORIS!!!!!!!!!!!!!!!!!!!!!!!!!
Title: Re: Thought I'd Blown the Mount up!!!
Post by: Fay on Apr 12, 2008, 20:35:42
Thanks Tony & Mick, I will go to Maplins & get all those bits on Monday
Title: Re: Thought I'd Blown the Mount up!!!
Post by: Rocket Pooch on Apr 16, 2008, 10:08:13
Fay,

Looks like you are having fun again.  I have to make some new cables for the Sphinx when I get back, get yourself up and running, when I'm making mioe I'll do you some fused cables for the mount with the appropriate battery connectors etc, will cost about £10 all in, if you want one let me know.

Also I think my eq6 uses 2amps during slew, 6amp fuses seem heavy?

Chris
Title: Re: Thought I'd Blown the Mount up!!!
Post by: Fay on Apr 16, 2008, 11:13:34
That is very kind of you Chris. I would like you to make me one. I have small croc clips & a new connector that goes into the mount.

Thanks a lot