Bob Buecher
newbie
Reged: 05/31/08
Posts: 2
Loc: Tucson, AZ
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I've just purchased an 'old' NexStar 11 GPS. Everything seems to work great except the Hand Controller. The middle row of keys (2,5,8 & 0) do not work at all. Telescope alignment works fine, but finding objects without those keys is impossible. First I tried cleaning the key contacts, no luck. Then I noticed that the circuit board is missing the D24 diode, it has obviously been broken off. The other diodes are marked '1B', which if look up on the web is equivalent to a transister (BC546B). That's not correct because what is missing is a 2 terminal chip. Does anyone know what the correct diode is?
This is, I think one of the original Hand Controllers as it has version 1.2 software and is not upgradeable. I know that I can buy a new HC but I'd like to see how much use I get out of the scope before sinking any more money into it.
I have been able to somewhat limp along by using a computer hookup to control the scope. But mousing the controls while looking through the eyepiece is awkward.
Thanks,
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Bob Griffiths
Post Laureate
Reged: 10/10/05
Posts: 4195
Loc: Frederick Maryland
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This is a tough one for you...but it would be sn easy decision for me because while I can turn a wrench with the best of them I have absolutely no knowledge of electronics so I would not be able to fix the darn thing...
Check of all places E-bay ...I noticed that quite a few older hand controllers were showing up for sale after Celestron stopped their trade in program (75 buck credit for sending you old one in) when buying a new one...this also gives you a fair idea of what the old one is worth...(no more then 75 bucks..working)
IF you also belong to an Astronomy club ...you may ask around to see if any owners of the GPS s11 scope did in fact upgrade to Skyaligh BUT opted to keep their original HC as a spare (I did not trade my original HC in when I upgraded and many people did not) ..they might loan it to you or maybe even sell it to you...
Nice thing however is for 150 bucks you can buy a new HC
which does have some nice extra features over the original one,, is upgradeable but in all honestly works no faster nor is any more accurate then the original ...
Lots of luck
Bob G.
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CPC1100
Nexstar 8i + GPS & Rays Brackets
Denk S1 power switch
Orion 100 mm Refractor
Meade LXD 55 ...AR-5 127 mm Refractor
Exploradome Observatory S.I.E. (Smiling Irish Eyes)
39*21'03" N
77*28'12" W
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mclewis1
Thread Killer
Reged: 02/25/06
Posts: 2454
Loc: Colorado
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Bob,
Interesting dilemma. I agree with Bob G that the $150 would be money well spent but I have another option for you. Would you like to borrow an old NS11 hand controller for a while? PM me and we can discuss this if it makes sense to you.
I was thinking I could open mine up and answer your diode questions but then I remembered what a pain it was to reassemble properly (getting the display to sit straight).
Another option is to enhance the PC control aspect with a Logitech game controller (Rumblepad or the like), the ASCOM driver supports one of these quite well, it would give you the equivalent of the HC arrow keys while at the eyepiece.
By the way ... welcome to CN.
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Mark
C11, C6, APM/TMB115, and AT80ED
Tandem mount CGE and CG-5A, WO EZ-Touch and AT Voyager
25x100s, 8x56s, T-Mount Light, and Mark 1 eyeballs
Modded 350D, SPC900, Mallincam
Edited by mclewis1 (06/02/08 11:34 AM)
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Tel
Carpal Tunnel
Reged: 03/31/06
Posts: 2631
Loc: Wallingford England
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Hi Bob,
Equally, a hearty welcome to CN !
A great gesture and advice from Mark !
Alternatively, if you really want to attempt the repair, did you think of asking "next door" on the "Nexstar GPS /CPC Forum". Might just be a better base of knowledge than here, bearing in mind the 'scope model ?
Best Regards,
Tel
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Truth is the cubed root of Verbosity.
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Greg K.
Reged: 12/11/03
Posts: 10002
Loc: Clifton Park, NY
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That's a good idea, Tel, and I'm going to take the liberty of moving this thread over there (but keeping a link in NexStar)
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NexStar 11 GPS
Orion SkyView Pro 8EQ w/ Autostar
15x70 Celestron SkyMasters
Orion 90mm Mak
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Greg K.
Reged: 12/11/03
Posts: 10002
Loc: Clifton Park, NY
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BTW, Welcome to CN, Bob.
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NexStar 11 GPS
Orion SkyView Pro 8EQ w/ Autostar
15x70 Celestron SkyMasters
Orion 90mm Mak
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rboe
Numbfinger
Reged: 03/16/02
Posts: 39739
Loc: Phx, AZ
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Since you are in Tucson you may want to ask the folks at Starizona if they happen to have any controllers.
Other options involve spending money too - like NexRemote if you have a laptop. Then you won't need the handcontroller.
But if you are looking at ever selling the scope a working hand controller is going to be a must.
Comet to think of it, you'll need the special cable (they use two different kinds of cables) to attach to the port under the handset (at the bottom) then to your laptop - then you can use any software package that can control a scope to control yours once it has been aligned.
Some of the software is free, the cable is "cheap" and of course you need a laptop. 
Welcome to Cloudy Nights! Check out our little sub forum on star parties; we have some nice get togethers over the year and many have more than one NS11 owner showing up.
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Ron
NS11GPS
Pronto
16" dob
15X70 Obies
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kx9i
super member
Reged: 03/04/08
Posts: 112
Loc: Phoenix, AZ USA
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Since you do know what a diode is, try to find a HC that is identical to yours and open it up. At best you'll see a part number on the diode you're missing. You can compare them side-by-side, as well, to find out if anything else got knocked off. Good luck!
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rboe
Numbfinger
Reged: 03/16/02
Posts: 39739
Loc: Phx, AZ
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The flip side of that; I can't imagine what it took to knock those components off the circuit board and there is a good chance the parts aren't missing; just an abandoned part of the circuit, but if it is damaged my gut feeling is to replace the entire handset to save headaches later.
Still, comparing two handsets from the same generation would not be a bad thing to do.
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Ron
NS11GPS
Pronto
16" dob
15X70 Obies
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Greg K.
Reged: 12/11/03
Posts: 10002
Loc: Clifton Park, NY
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Well, he said it had "obviously been broken off", so there may be part of the lead still there. The controller would have had to have been disassembled in the past for that to be broken off though.
A new controller is the safest bet. OTOH, it's already broken, so he's not likely to make it any worse by trying to fix it. 
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NexStar 11 GPS
Orion SkyView Pro 8EQ w/ Autostar
15x70 Celestron SkyMasters
Orion 90mm Mak
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Greg K.
Reged: 12/11/03
Posts: 10002
Loc: Clifton Park, NY
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Found a link:
http://www.dd1us.de/Downloads/N5i%20handcontroller%20heating%201_0.pdf
Page three shows some close-ups of the diodes in question. Assuming it's similar, these are tiny surface mount diodes that should prove a lot of fun to solder on by hand.
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NexStar 11 GPS
Orion SkyView Pro 8EQ w/ Autostar
15x70 Celestron SkyMasters
Orion 90mm Mak
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Bob Buecher
newbie
Reged: 05/31/08
Posts: 2
Loc: Tucson, AZ
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Success!
All I really needed was to know what type of diode to use.
The D24 diode is a surface mount device, very small, and has the designation 1B. I've been trying to find out what diode corresponds to the 1B designation.
Tonight, I took a guess that it might be a 5.1 volt zeiner diode since the controller operates on 5 volts. I didn't have a 5.1 volt zeiner lying around but I did have a 4.7 volt. This was a diode with leads and huge compaired to the lost surface mount one. But with globs of solder I got it in. And , wonder of wonders, the Hand Controler now works!
I won't be able to take the scope out until tomorrow but now I can enter all of the lost digits and other functions associated with those keys.
Thanks for all of the suggestions!
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Greg K.
Reged: 12/11/03
Posts: 10002
Loc: Clifton Park, NY
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Good going! 
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NexStar 11 GPS
Orion SkyView Pro 8EQ w/ Autostar
15x70 Celestron SkyMasters
Orion 90mm Mak
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StarWars
Postmaster
Reged: 11/26/03
Posts: 11644
Loc: Cyber Space
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Well, for $150 you can upgrade to the Sky Align HC...
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Sony Digital Media player..
MX 460 earbuds
15x70 ETX125AT
FireBall XL5
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rboe
Numbfinger
Reged: 03/16/02
Posts: 39739
Loc: Phx, AZ
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Nice going!
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Ron
NS11GPS
Pronto
16" dob
15X70 Obies
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hobbyking
newbie
Reged: 06/27/08
Posts: 4
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It is a hybrid pc mount diode and looking at the pics its not high current. I would try a signal diode and make sure the cathode is soldered to the +. The cathode will have a black solid line on one end of it. Also look at the ones around it and get some numbers off them it might help.
The keypads are an elastomer conductive type material on the buttons. Clean them with rubbing alchol and que tip gently, the buttons and the pc board.
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Chris Rowland
member
Reged: 02/28/05
Posts: 25
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There's a scematic diagram in the files area of the NexstarGPS Yahoo group, this shows it as a normal diode, not a Zener.
Chris
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