Orpington Astronomical Society

Astronomy => Technical => Topic started by: Fay on Jun 27, 2010, 00:24:42

Title: SX problem
Post by: Fay on Jun 27, 2010, 00:24:42
My SX brick light comes on when plugged in, but goes off when the camera is plugged in.I have tried it in the mains, from 12V battery & the result is the same, light goes off.

Has anyone any ideas please. The brick is quite hot & the metal connector that comes from the camera & plugs into the brick, is very hot too.
Title: Re: SX problem
Post by: Mac on Jun 27, 2010, 01:20:47
hmmm i suspect some sort of short circuit thats dropping the voltage.

Not a full short, just a partial.

You will probably find the blinking light indicates a low voltage,
and when you plug your camera in its enough to drop the voltage low enough to turn off the SX, hence the led going out.

Mac.
Title: Re: SX problem
Post by: Mike on Jun 27, 2010, 09:33:19
Agreed. If I were you I wouldn't plug your camera in again until it is sorted as you might damage that too.
Title: Re: SX problem
Post by: Fay on Jun 27, 2010, 09:47:13
So you think a cable could be broken?
Had a reply from Terry Platt, who says, sounds like short circuit in cable from camera, same as you
Title: Re: SX problem
Post by: Mike on Jun 27, 2010, 09:58:08
Mine was a blown transistor on the board inside the camera.
Title: Re: SX problem
Post by: mickw on Jun 27, 2010, 10:01:42
Fay do you wind your cables round whatever your using when you pack up or do you unplug the cables and coil them separately ?
For instance - wrap USB cable round a camera or unplug it and coil it neatly

When you wind a cable round something there is a tendency for the cable to twist and eventually break.  There is also the chance of straining the plug
Title: Re: SX problem
Post by: Fay on Jun 27, 2010, 10:08:51
well, I will confess, Mick, that I do not pack the cables very well. They are normally quite rigid after being outside in the cold, hence, it could be the cause of my problem.

I have mailed Terry, to see what I should send off to him, so they can have a look
Title: Re: SX problem
Post by: Ian on Jun 27, 2010, 10:17:15
I'm with Mike on this one. Switchmode power supply chopping transistors can fail, but still provide a small amount of current. As soon as you put a load on the transistor shorts and the output voltage falls.

Replacement time I'm afraid :(
Title: Re: SX problem
Post by: Fay on Jun 27, 2010, 10:23:32
I forgot to say that I also tried the little orange connector/cigarette adaptor that goes into the jump start, still did not work.

Ian, what are you saying????????????camera no good??
Title: Re: SX problem
Post by: mickw on Jun 27, 2010, 10:41:22
If the cables are rigid and cold it means the insulation will very likely be brittle.  When you try and wrap it round something the insulation could start to crack which will only get worse leading to short circuits and other bad things.

If they become rigid do not try and wrap them round anything, take them indoors and leave them in a corner somewhere until the morning when they warm up and become flexible again.  Then you can coil them up loosely and put them away.
Title: Re: SX problem
Post by: Fay on Jun 27, 2010, 11:08:54
will do. I do throw a lot of them into the equipment box, but the camera one's do get put away at once, not any more
Title: Re: SX problem
Post by: Fay on Jun 27, 2010, 11:55:25
Terry Platt has given me a couple of tests to do, one involving taking the back off the camera & unplugging the white connector, plugging the brick with this disconnected to see what happens. The light on the brick was intermittent as I moved the cable around.

He said that the connection on the back plate may have an internal short circuit, & to send it off to him & he will have it replaced.

Such a quick service, on a Sunday too!!!!!!!!
Title: Re: SX problem
Post by: mickw on Jun 27, 2010, 13:29:12
QuoteSuch a quick service, on a Sunday too!!!!!!!!

God, you didn't ring him up and cry did you  :roll:
Title: Re: SX problem
Post by: Fay on Jun 27, 2010, 13:35:57
No, daft, i sent a mail :roll:
Title: Re: SX problem
Post by: Ian on Jun 27, 2010, 14:21:31
just the psu Fay... Although, I thought you meant that the LED was on the psu.

I'll let Terry do the debugging from here on :)
Title: Re: SX problem
Post by: Fay on Jun 27, 2010, 14:25:58
what is a PSU Ian?
Title: Re: SX problem
Post by: Mac on Jun 27, 2010, 14:56:53
Power Supply Unit
:lol:
Title: Re: SX problem
Post by: Fay on Jun 27, 2010, 16:52:11
Oh cool Mac! :cheesy: