CG5 goto mount slewing problems

[Astronut]

Me and Lulu just got back from a mini camping break at Lucksall prior to the next SGL gathering in March 2011. The new tent and camping equipment is fine but my CG5 goto mount has developed a fault.

I've had no real problems with it until the other night and it's hardly been used from new. I first noticed the problem as it was slewing to a new target and it stopped dead halfway there only to restart slewing after a pause of about 15 seconds. It missed the target and carried on slewing until the scope was pointing below the horizon at which point I powered off as it was obvious something was wrong. I powered on again and put the scope manually to the home position prior to inputting time, date, etc and starting another 2 star alignment.

The mount started slewing to the first star and stopped dead halfway there. Again, after a pause of 15 or 20 seconds, the mount started slewing again past the target, stopped dead again for another 15 or 20 seconds and started slewing again until the scope was pointing below the horizon. I powered off and resorted to manual slewing which seemed to work fine although I did notice that the mount didn't always stop immediately after releasing either declination button (sticking contacts, maybe?). Not sure if this is a coincidence but the red power LED on the mount is also no longer working.

I keep the 'scope and mount covered with a telegizmo cover when not in use so it's not water in the electronics of the mount or handset but could dew have worked inside causing a short in the electronics or some switch contacts, maybe?

I've done a quick search on 'tinternet and have come up with 'runaway slews' on the CG5 goto mount (seems to be a fairly common problem) but haven't found anything with the specific symptoms above.

Any ideas if this is easily fixable? It's still less than a year old but if its an easy fix, I'd rather do it myself than send it back for repair as I no longer have the original packaging for the mount and the C9.25 OTA has already been back twice (and may need to go back again!) but that's another story.

Ian

[lulu57]

Poor Ian.

As no one has a solution to your problem, may I suggest that you put your SCT worries from your mind and lavish all your attention on your voluptuous OH?

[Mark at Beaufort]

Sorry to hear about the problem Ian. I really enjoyed viewing Saturn through your SCT at SGL5.

If I knew you and Lulu were at Lucksall I would have 'popped' over to say hello.

Mark

[Astro_Baby]

No idea - sorry Ian - I know the HEQ5 and EQ6 pretty well but have no real experience of the CG5. It might be a lot of things. Is the power to the mount totally ok. It could be some sort of intermittent power supply problems.

Have you noticed if the red led is always off or does it sometimes come on ?

It sounds like some sort of intermittent power problem ie

1/ Mount starts its slew

2/ Power is interrupted

3/Mount comes alive again and 'resets' its slew so it overshoots

Thats just a real guess. Without being hand on is really hard to know.

My firts inclination (assuming its not a warranty job) woulkd be to open up the guts and see if all the internal connections are ok, any evidence of bad connections due to loose wiring. the CG5 has always struck me as having lots of wire and connectors on the outside which could cause problems.

Is the handset showing any error conditions when it does this - does it blink, fade, display an error code - anything like that ?

[Astronut]

I'm not convinced it's an interrupted power supply because the handset stays lit when the slew stops. The handset display is also intact ie. the information of which star it's slewing to is still displayed. Also the handset display doesn't flicker when the slew stops which would be indicative of an interrupted power supply. A new power supply lead is on its way so I shall try that first but going by the symptoms I've just mentioned I'm not holding my breath.

The LED going off could be just a coincidence. It doesn't work at all now but power is getting through to the mount and handset.

ps. Mark - we did think about you at Lucksall as we know you live very close by but we had no way of contacting you.