Motor stalled.......
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Hi, I would do a few things: First, contact the seller and talk about what you are experiencing.? Is that why they sold the mount?? ?If you cannot fix this can you return it? Second, to try and fix the problem, see if there is oxidation or corrosion on the cable connector pins.? If there is poor contact, then the signals from the motor encoders will be missing or noisy, and the (Gemini) will try to run the motor looking for the encoder signal.? If the encoder is bad, the system will just keep trying to put in power to get a signal.?? Third, ... sometimes cables go bad also.? Try swapping the RA and DEC cables. ? ?Be very very careful putting on the cables.? There is a "dent" identifier on the cable connector, but these cables can be forced into their sockets with damaging consequences.? In the dark it is easy to make a damaging error.?? Fourth, be sure the Gemini says it is connected to a G11 mount.? There are many mount options and sometimes the system (especially with a weak/bad internal 3V backup battery) will default to a different model mount.?? I'm out of ideas for you.... sorry! Best, Michael On Sun, Oct 8, 2017 at 6:03 PM, mknwfhccabsgfi2b7fvsii57vq43ikvdv4r3sfuo@... [Losmandy_users] <Losmandy_users@...> wrote:
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hmmmm... a good puzzle.... Try this: set the Gemini to "terrestrial" tracking which means it will not drive RA or DEC.? ? If you do that, neither RA or DEC should move. If the Gemini is still driving the DEC, there is one possible cause: the handset serial cable, or the handset itself can have an intermittent contact in the diamond switch (North South butttons moves the DEC only).? ?Try removing the handset from its cable.? If the DEC stops moving, then it is a flaw or short in the handset.?? To remedy that, unscrew the 2 Phillips screws in back of the handset. Open the handset case.? Look for and clean any discoloration or residue on the ribbon cable or its connector, and on the circuit board, using a cotton swab dipped in alcohol.? Usually this clears up any slight surface short.?? Hope you get this cleaned up and enjoy your system... Best, Michael? On Oct 8, 2017 18:58, "mknwfhccabsgfi2b7fvsii57vq43ikvdv4r3sfuo@... [Losmandy_users]" <Losmandy_users@...> wrote:
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If it is the U15 or U16 chip, then David Partridge in the UK has these or can make them. I have not yet tackled that.? These chips are in sockets on the main board and can easily be? pulled out (say with an automotive sharp hook tool) and replaced by the owner. If it is the motor's encoder element, then, again, I have no experience with that trouble.?? In either case, I am surprised the prior owner did not experience the problem and that John, who? just acquired the system, is stuck with this problem from his first experience.?? Best of luck, Michael On Sun, Oct 8, 2017 at 9:26 PM, brenatlilydale@... [Losmandy_users] <Losmandy_users@...> wrote:
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Most likely problem here is either the motor shaft encoder, followed by the quadrature decoder ICs.
I can fix either of these problems (I live in the UK) as I am sure can Michael Hermann (CA) and Bren Smith (Australia). Dave From: Losmandy_users@... [mailto:Losmandy_users@...] Sent: 09 October 2017 02:03 To: Losmandy_users@... Subject: [Losmandy_users] Motor stalled....... Hello all, New member here, with a problem. Ok, I just picked up a used G11 with Gemini 1 level 4 version 1.05. When trying to align to a bright star the dec motor show's motor stall. I figured something must be binding, so I took out the motor and tried it again, same thing, eliminating possible worm binding. After restarting the system I noticed that after putting the mount in sidereal rate the ra motor seems to spin at a that I would expect but the dec gear is spinning at a few hundred rpm not with enough torque to move the mount. Then when I try to align on the hand controller, it speeds up to a high rpm for a split second then shows the error. When turned off the motor turns by hand freely. The power supply that came with it is at 12v so I tried a higher voltage one at 14.5v, no different. Where do I start? Thanks John |
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Losmandy no longer repair G1 L
Dave From: Losmandy_users@... [mailto:Losmandy_users@...] Sent: 09 October 2017 05:27 To: Losmandy_users@... Subject: [Losmandy_users] Re: Motor stalled....... John Seen this before in DEC and RA, repaired a DEC one not long ago (hope its not same one doubt it).. Unfortunately it's a bad DEC encoder IC. Yes there is a remote possibility its a DEC motor itself or DEC H bridge but I'm pretty sure its as I said. Upon switch on both motor pinions lock...aka they are applied drive voltages on both sides of their H bridges. Their pinions will have major resistance to movement and be difficult to turn (if you can and do it will log a boot fault in the HC). When you see the HC msg "system boot at xxxx....xx" the Ra pinion starts driving at sidereal rate., the DEC will stay locked resistant to movement and will only move if commanded. On the system I repaired that had the same symptoms and bad DEC encoder IC (above), the DEC pinion was weak and rotated slowly on pwr on and drove crazy if one of the HC DEC buttons was pressed. Both Ra/DEC motor encoder ICs U15/16 are firmware installed. Repairer: Rene? (Germany); David Partridge (UK); Michael Herman (USA); Me (Australia); Losmandy (USA)...anyone I miss? Brendan [Non-text portions of this message have been removed] |
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Not tried to read those yet, it is the soldered on quadrature decoder chips that I can make. The PIC17C42 ICs I have yet to attempt.
Dave From: Losmandy_users@... [mailto:Losmandy_users@...] Sent: 09 October 2017 06:48 To: Losmandy_users@... Subject: Re: [Losmandy_users] Re: Motor stalled....... If it is the U15 or U16 chip, then David Partridge in the UK has these or can make them. I have not yet tackled that. These chips are in sockets on the main board and can easily be pulled out (say with an automotive sharp hook tool) and replaced by the owner. If it is the motor's encoder element, then, again, I have no experience with that trouble. In either case, I am surprised the prior owner did not experience the problem and that John, who just acquired the system, is stuck with this problem from his first experience. Best of luck, Michael On Sun, Oct 8, 2017 at 9:26 PM, brenatlilydale@... [Losmandy_users] <Losmandy_users@...> wrote: John Seen this before in DEC and RA, repaired a DEC one not long ago (hope its not same one doubt it).. Unfortunately it's a bad DEC encoder IC. Yes there is a remote possibility its a DEC motor itself or DEC H bridge but I'm pretty sure its as I said. Upon switch on both motor pinions lock...aka they are applied drive voltages on both sides of their H bridges. Their pinions will have major resistance to movement and be difficult to turn (if you can and do it will log a boot fault in the HC). When you see the HC msg "system boot at xxxx....xx" the Ra pinion starts driving at sidereal rate., the DEC will stay locked resistant to movement and will only move if commanded. On the system I repaired that had the same symptoms and bad DEC encoder IC (above), the DEC pinion was weak and rotated slowly on pwr on and drove crazy if one of the HC DEC buttons was pressed. Both Ra/DEC motor encoder ICs U15/16 are firmware installed. Repairer: Rene? (Germany); David Partridge (UK); Michael Herman (USA); Me (Australia); Losmandy (USA)...anyone I miss? Brendan -- Michael Herman mobile: 408 421-1239 email: mherman346@... [Non-text portions of this message have been removed] |
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The decoder ICs U15 and U16 are no longer obtainable from Losmandy or Aveox. However they are just AFT16V8BQL-15SU PLDs which need to be programmed.
I have the jedec file to program them if you have a suitable programmer and SOIC adapter. The two ICs are the SOIC-20 parts at the upper right edge of the G-1 PCB. You'll need hot air soldering kit or "Chip-Quik" to remove them. If you aren't comfortable doing that then either Michael Hermann or I can repair for you (I'd suggest Michael if you are in USA as I live in the UK). You can test the shaft encoder with the motor removed from the mount and without the Gemini controller. Use a 5V supply, ground to pin 1, +5V to pin 4 of the HEDS-9100. You can then turn the motor pinion by hand and observe the signals on pins 3 and 5 HED-9100. If you only get a signal on one or neither, then replace the encoder. Clear skies Dave Partridge |
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I have fortunately not found Gemini units with this damage - yet.? I cannot yet do that repair, as I have not yet developed the programming kit to make these replacements, but I will look into that.? ? Better: how can we Gemini owners prevent such damage in the first place? Can anyone say what is causing these chips to fail??? Is there a simple preventative measure owners can take to avoid such damage? Best, Michael? On Oct 10, 2017 4:33 AM, "'David C. Partridge' david.partridge@... [Losmandy_users]" <Losmandy_users@...> wrote:
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Hi John, You can reach me, Michael Herman, at? email: mherman346@... or by phone (I'm in California) at 408 421-1239 I suggest you call me to discuss this problem.?? Best,? Michael On Tue, Oct 10, 2017 at 7:50 AM, mknwfhccabsgfi2b7fvsii57vq43ikvdv4r3sfuo@... [Losmandy_users] <Losmandy_users@...> wrote:
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OK.?? I see the chip listed here in the Mouser catalog as: Atmel made these in the 20-pin SOIC (small outline IC) package -- no one else made the product in that package.?? They are $0.95 each from Mouser, + lowest shipping charge $5.?? The datasheet is here:? The problems will be getting a DIP to 20-pin SOIC socket to program these, and to see if my existing programmer with its DIP socket will work..?? It is ironic that Atmel is near me in San Jose... they got bought by Microchip recently...? Best, Michael On Tue, Oct 10, 2017 at 8:09 AM, mknwfhccabsgfi2b7fvsii57vq43ikvdv4r3sfuo@... [Losmandy_users] <Losmandy_users@...> wrote:
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OK.? I've ordered 10 of these chips, and I found a 20-pin DIP to SOIC socket on eBay to allow me to program these. Next steps... await the experiment... of giving it a try.... and talking to John...! Best, Michael On Tue, Oct 10, 2017 at 8:42 AM, Michael Herman <mherman346@...> wrote:
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Michael Herman
David C. Partridge