Meade LXD 75 fault help needed.

[Fish]

My mount lives outside in my obsy including my hand controler.

The fault developed the other night when slewing to target, I use stellarium to slew to target in this instant the target was not in the eyepiece so I did a spiral search, as soon as I toutched the button the mount slewed out of control for a short while then stopped. I then parked the scope and did a slew to the moon and it worked fine, then while useing the direction buttons it did it again, this time I noticed that only one of the direction buttons functioned. It was late so parked up and hoped it was dew causing the problem.

Out tonight and exactly the same again , this time I spent a bit more time playing with things and it seems like if I wiggle the cable I can get the slew buttons to work ,sometimes again slewing on its own . When I use the pc to slew and dont toutch the handset all seems ok but obviously I need to use the hand control. Searching on google it appears it may be bad contacts on the plugs or corroded keypad .

Thought I would ask here to see what you all think before I go any further as you probably know exactly what it is (fingers crossed).

[ronin]

My first thought was the handset is worn.

Hot/Cold/Damp/Dry cycling outside causes things to age.

There is a membrane in there and that is one likely culprit.

If not that specifically the contact get corroded for the same reasons.

Think I have read of people taking them apart and cleaning contacts etc up, but if the membrane has perished then cannot think of how to get a replacement.

Didn't Opticstar take on the Meade support ?

[russ.will]

First things first. Try a full reset from the Ultilities menu.  Can't hurt and a few have reported that it's solved a variety of ills.

Check the handbox cable and contacts in the sockets in both the HBX and the mount. Cables are comfortably the least reliable element of anything and the cheapest to replace and sometimes, inexplicably, the contacts in the sockets get bent and/or flattened- straighten/lift them with a pin.

There's plenty of resource on reconditioning the keypad, such as this site, as you will have found. But normally, a keypad requiring that sort of treatment will simply not make a contact, not make a contact and stay stuck, which is what you might expect from the run-away slews.

I have read of one or more of the capacitors dying in the #497 and this could result in what you are experiencing. Capacitors do not like power cycling and extremes of temperature aren't exactly their favourite either. Generally, they prefer to remain powered up which keeps them temperature stable and avoids the initial high current charging shock. The symptom is as per hi-fi amplifiers where all powers up well, works nicely and then during use, noise and breakup of sound starts to happen. Over time, it takes less and less time for the breakup to start happening.

Replacing the caps (if it is them), much like refurbing the keypad, isn't hard if you know which end of a soldering iron gets hot, but it may just be as easy to cut your losses and run with a new #497.

I'd then suggest (and this is me thinking out loud) sleeping the scope when not in use, not turning it off. The motors will have stopped, but the #497 be getting power keeping it warm and dew free and preventing power cycles. 

Russell

[Fish]

Thank you for that info Russel, so far I have stripped and cleaned the keypad . My mount is quite a few years old and I was expecting to find some grime inside, I was amazed it looks like new still. Gave the contacts a clean and the carbon inserts , checked for dry joints and checked all was well with the connector. I then checked the cable and it checked out just fine.

I will check the other cable next and give it a reset . One thing that has been happening of late is when I power it up it does not start it just sits with the red led's on but no display, cycle the supply and all is good, not sure if this is related. I should get some free time to look closer on Saturday.

Unless I can find a #497 sale or return I will have to decide if its time to get a new mount :-( , but I do love my LXD75 ....

[russ.will]

If there's nothing wrong with the mount, why not bung new motors and a handset on it? It's still currently sold as the Bresser EXOS2 GOTO, which I had and loved. Have a search, but there is an upgrade kit for the non-GOTO (a #497 and motors as per your LXD75) at about £320. You can't get many mounts with roller bearings on all axis for that and it will pick up exactly where you left off.

There is also a new Bresser Startracker handset and motors (seen it - much beefier motor housings) that is shipping on EXOS2 GOTOs now. The one I played with was really nice, with slightly more positive buttons and far more information on the screen than the SW/Big C/Meade ancient fayre - Much more like iOptron. I don't know the price, but may be worth a look.

Russell

[russ.will]

Hold the phone - Found it. 250 euro is about £190 at the moment. 

Russell

[Fish]

That looks so tempting but im not sure I would have the ability to get it all together, and my German is not very good. Looking like this is not going to be as clear cut as I thought.

Again thank you .

[russ.will]

Honestly, all the screw holes are there and even if the kits didn't come with screws, you already have the ones that matter. The gears shown in the kits are for those converting from manual slo-mo controls so, theoretically, you don't even need them. I would though, because it never makes sense to use new gears against old.

I had my EXOS apart a couple of times to finesse the worm as it bedded in. It really is something you can do with a few allen keys and a screw driver or two.

Russell

[alan potts]

My LX 12 inch has done this a good few times and then it is fine for ages, I have kept mine outside for years now. I have never really come up with an answer other than a poor connection somewhere, lets face it the this is not the best connection system from handset to scope, just look at the amount of pulling, twisting and turning it goes through. The other thing it could be it poor unstable voltage from a transformer or battery, this is a source of many EQ 5&6 problems.

My money would be on the cable from the handset to the mount though.

[Fish]

Thanks for that Alan , I have checked the resistance of each conductor while being manipulated and it seems fine. I have emailed Bresser to find out if I can order the upgrade kit in the uk . Im going to rule out the power supply and check that its still 100% broke after a reset. If so I will strip and inspect the gears and adjust the backlash , if all is well I will probably try the upgrade kit.

[russ.will]

A word to the wise; With the £GBP sitting at 1.38 to the Euro, it will be one heck of a lot cheaper to buy it from Astroshop.eu, Teleskop Express, APM Telescopes, etc. I've dealt with all of them and in terms of speed of response, customer service and shipping, you wouldn't know they weren't in the UK. Your covered by the same set of distance selling regulations anyway.

Russell

[Fish]

Managed to track the fault, I had checked the cable 3 times and every time I checked it the resistance was equal on all 8 pins. While doing some further testing I found that squeezing one point on the cable gave me a functioning mount for a few seconds , this sort of convinced me it must be the cable . I had an old ethernet cable so cut and re-configured it to test my mount. Pleased to say that it works fine :-) so just need to get a new cable. After further testing of the cable I did find the faulty cable on pin 4 , not sure what its function is but it sure throws up a cracking fault.

Thanks for the help guy's .

[goose35]

Just had an exos 2 mount of the bay and used it for an hour and love it(suppose i would after a cg-3 ).

Dread it ever going wrong but this thread was a good read just incase thanks

[Fish]

Sounds good , I love this mount. Mine gets some abuse sometimes weight wise but never complains. If you have the option consider turning on the quiet slew option found under settings I think. Makes for a quieter mount and prolongs gear life at the expense of a bit of time. Hope you enjoy your new mount .

[m.tweedy]

there is a site dedicated to LXD55/75

http://www.weasner.com/lxd/

I am sure you should find the answer ther

[russ.will]

Just had an exos 2 mount of the bay and used it for an hour and love it(suppose i would after a cg-3 ).

Dread it ever going wrong but this thread was a good read just incase thanks

Was that one from Nottingham with two counter weights? If so, that was mine a few weeks earlier and it may need a bit of tweaking in the DEC axis, as there was a bit of slack in it. I was going to do it, but the decision to sell came on a bit quick and I didn't get round to it.

Read the Weasner site. It's a wealth of information.

Russell

[goose35]

Small world. Yeah ive done the dec tweak all ready spotted it on first outing cheers