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Re: Cable needed: Gemini2 Serial port to USB connection with FTDI.
On Tue, Nov 5, 2024 at 10:25 AM, Roger Smith wrote:
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Ah, I see. You'll need an FTDI-based USB to RS232 adapter, usually with a 9 pin DB9 connector, such as .
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Then, you'll need the DB9 female to RJ12 male cable with the correct pins connected. It is much easier to get this one pre-made for you, already wired correctly. Unfortunately, the pinouts are not exactly standard, so unless you find a cable for sale that's serial port, you'll need to either wire one yourself, or find one with the correct pins already connected.? Something like can help wire these.
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Re: Cable needed: Gemini2 Serial port to USB connection with FTDI.
On Mon, Nov 4, 2024 at 08:44 PM, Roger Smith wrote:
Hi Roger, what connector is at the output of your FTDI converter? Maybe share the model # so we can look it up.
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Re: G11G DEC Stall
On Mon, Nov 4, 2024 at 03:01 PM, Fritz wrote:
I'm sure the new board will fix the issue, Fritz. Too bad you had to buy a whole new one, as it sounds like the fix may not be very complex or expensive. But in the interest of time, that's probably the fastest way to get your Gemini back up and running.
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Good luck and let us know how things work out.
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Regards,
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Re: G11G DEC Stall
Thank you all again for the incredible amount of background and help! I talked to Michael Herman in detail on the problem and it was decided that likely the best course of action is a replacement board.
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As John Kmetz pointed out a replacement board used to be $300 which imo is a very fair price or a board with common parts and in production so long. It is now $700 for just the board.?
Sometimes it is a trade off of time vs money with enjoyment of a hobby, and in this case I do not have the time go down a potential rabbit hole with the board and miss out on the imaging season in Florida. I skipped last years imaging season to build my new observatory so I’m really looking to start imaging again.?
I’m certainly confused why the board is so expensive now and it leaves a bad taste in my mouth but it is what it is. I was also unable to get a hold of anyone at Losmandy since the beginning of this post (email or phone). The board was ~7 years old and always kept in an environmentally controlled environment. My observatory has both an air conditioner and a dehumidifier.?
Thank you all again for your help and giving so much to the community. I’ll report back if this is the fix. Looks like the replacement board shipped out today.? |
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Re: G11G DEC Stall
Paul is totally correct.?? In general all Gemini's are repairable, 1s and 2s. ?? The only thing holding back some repairs may be PCB corrosion or intermittent faults!??? Older G1s are mostly a cake walk but some parts are getting to be a supply issue, also aged PCBs' and moisture are its enemy to its tracks and Pads (after decades of user service).??? Since covid, electronics parts have either become obsolete or increase in price for repairers. ? Its an immutable fact an G1 "H" bridge was $11~$15 AUD ...nowdays $61 AUD and getting rare to source.??? Repairers cannot buy from fleabay...the reasons obvious thus must buy from proper spare parts houses! ?? Easier for Losmandy as they buy parts in 1000's....plus some.
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The equivalent "H bridge" IC on the G2, are now a little cheaper ~$15 AUD. ? But it’s not an easy IC to replace due to its base thermal heat sink pad. ? ?It’ll test even the best skills.?
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Losmandy/Axeox made these PCBs easily accessible to replace ICs aka "repairable".?? But due to the nature, especially, G2s. SMD ICs R&R and firmware can be tricky and more specialist in nature for repairers to perform.? I've seen some damage that defies belief but managed to be repaired.? All repairers, Losmandy, others, Paul et el can do, R&R like this.
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But when you see things like this....see pic......Little did I know that it also took out the 144pin ARM (though I had suspicions and told owner this before starting) ...but R&R'ing that IC (easy enough) then ARM not so easy.....(then doing ARM boot-loader and fimware), Rene' saved me (once again) on that.? This was a more difficult repair but, it's was done dusted and returned fully repaired and at a fraction lower costs of a new board.? We are more and more becoming a "throwaway society" which is sad to see.?
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Bad drive issues on the Gemini...can be many issues caused by many things:.... but these are made to be repaired and servo mechanism is "bread and butter" stuff repairs for those who know the cct'try.? I enjoy doing repairing such......giving the community something back as it has given me so much in return.
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And no that crater is not by me....it vaporised the top of the ST4 interface buffer IC and blew it off and damaged the ARM processor.?? This PCB was fully repaired, still works today, at a fraction of replacement cost.? Still I understand some users like to have spares, so the are not without.? If you do "throw in a spare"...send your old board for repair...you will be surprised and may need it again some day!.
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Brendan |
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Re: In search of 492 systems for G11 and GM8
On Tue, Oct 29, 2024 at 05:08 PM, John Nassr wrote:
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I think you are mixing up the #492 Digital Drive - "DD"? with the original low resolution encoder Losmandy Digital Setting Circle - "DSC" systems.? The #492 DD is the original tracking but non-GOTO geared stepper motor powered RA and DEC drive system intended for visual and imaging use with a "dumb" hand controller or an autoguiding camera.? The Losmandy DSC AFAIK ad 4096 tic encoders and it was okay.? That said the low resolution encoders are no match for the modern high resolution 311,000 tic encoders and Wi-Fi equipped Nexus DSC from Astro Devices.??
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I have a very early 1992? Losmandy GM8s #492 Digital Drive mount with Astro Devices 311,000 tic encoders and Nexus DSC Pro.? Together they make what has to be the finest lightweight moderate payload PUSH-TO mount available.? The GM8s with Nexus DSC is my favorite visual mount even though I also have a new GM8G2 and 20 year old but current spec G11G2.? ? ? ? ? ?
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Chip Louie Chief Daydreamer Imagination Hardware? Astrospheric Forecast - South Pasadena, CA? ?
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Re: ASIair connection via USB to G11 w Gemini2
On Mon, Oct 28, 2024 at 05:21 AM, Roger Smith wrote:
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Well for a USB connection I do the same thing as using Ethernet, my tablet or phone should already be turned on then I manually level the mount head using the bubble vials in the mount base then using a level on the CW and saddle or your pre-marked CWD indicators on the mount head.? Then I power up the Gemini 2 and once I get to the top diamond display after power up (this can vary depending on how the Gein 2 is set to boot up) I power up the ASIAIR and wait for the two sets of beeps telling me the ASIAIR has booted and loaded its firmware.? Then I connect the tablet/smartphone Wi-Fi to the ASIAIR SSID and open the ASIAIR app, select the ASIAIR device and make the connection to the app.? The app opens up and should show you all the connected peripherals the ASIAIR can see, the Gemini 2, ZWO imaging camera, ZWO guide camera, ZWO EAF, ZWO EWF etc.? the menus are self explanatory.??
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Chip Louie Chief Daydreamer Imagination Hardware? Astrospheric Forecast - South Pasadena, CA? ?
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Re: Purchasing a G11 with last version of the Gemini-1 controller
On Thu, Oct 31, 2024 at 03:31 PM, Brendan wrote:
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IDK about bad juju but poor form maybe?? ?Just yanking your chain...
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Chip Louie Chief Daydreamer Imagination Hardware? Astrospheric Forecast - South Pasadena, CA? ?
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Re: G11G DEC Stall
The problem with a single axis is often caused by the PIC controller (the same one that was programmed with the L6 release). There are two of them, and it's a small SMD chip, not easy to replace without some experience or expert guidance (thank you, Brendan!) It is much cheaper to replace than getting a new board. Our helpful can all do it, so don't assume you need a whole new board if just one of the axis isn't working with a motor that is otherwise functional.
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Regards,
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On Thu, Oct 31, 2024 at 12:31 AM, John Kmetz wrote:
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Re: Purchasing a G11 with last version of the Gemini-1 controller
On Thu, Oct 31, 2024 at 12:04 PM, <tpolk0202@...> wrote:
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Hi Tom, Gemini-1 is fairly old and so electronics and motors need to be tested to make sure everything still works. The G11 mount itself can require some testing and possibly servicing. The good thing there are still many parts available to repair G-1 should things not work, including motors. The mount itself should be serviceable and can (depending on age) be brought to the latest spec with parts available from Losmandy.
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If everything is assembled together, then a functional test would be to:
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1. Put an OTA on the mount, balance it well in RA and DEC. Put the mount into rough counterweight-down position (CWD).?
2. Connect Gemini and the motors, boot up Gemini. Make sure it goes all the way through to displaying text on the hand controller. If it gets stuck with some dots visible, there are issues with the controller. Pay attention to any error messages, such as stalled motors, lag messages, etc. -- these are indication of either bad motors or poorly adjusted worm/worm-gear, or possibly poorly balanced mount or mount that needs regreasing.
3. Try using the hand controller buttons (make sure the mount is set to Visual mode) to slew the mount in all four directions. While slewing with RA and DEC motors, touch the outside of the corresponding motor -- warm or hot motor could be an indication of existing problem or problem to come
4. Make some changes to settings (like geo-location or time). Turn off Gemini for a few minutes, turn it back on. Are the settings still there? If no, there's a 3v coin battery inside that may need replacing.
5. If the seller has a PC with Gemini.NET ASCOM driver on it and a serial connection to Gemini, it would be worth a test to make sure the PC can connect to Gemini over serial port.
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There are many more things that you'll need to check assuming this works fine, but most will require stars.
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Double check that the controller is at least updated with Gemini L4 v1.04 or v1.05 -- these are the latest.
Most of the modern software that uses ASCOM will work with Gemini-1 if you have a serial connection to the mount from your PC. Some software packages know how to talk to Gemini directly, without ASCOM, and some use INDI drivers. Not all of these will work with G1, but most should.
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I believe others may give you a more in-depth advice as to what and how to check.
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Regards,
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? ? -Paul
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@fvitale
Paul Kanevsky
Fritz
Chip Louie
Ed Harp