Re: Thoughts/recommendations concerning repair of Gemini 1
You may want to contact Micheal Herman...he's the go to guy for Gemini repairs.?? You can reach him at Michael Herman <mherman346@...>? As an aside I just noticed in your that he picture updated your memory/eprom? back in 2022
|
Thoughts/recommendations concerning repair of Gemini 1
Well I did it.
I inadvertently used the wrong cables for the motors and smoked something. I used 6 pin RJ connectors instead of 8 pin RJ connectors. The display was working fine until I pressed a button on the hand control and it clicked, went blank and I smelled it release smoke inside.
Pulled the cover but don't see anything obviously fried. Installed the correct cables and powered up (cover removed).
?
It powers up but the Dec starts running - not exactly slewing but moving pretty fast. As soon as I touch an arrow button the Ra starts slewing. The only way to stop either is power off.
?
?
I appreciate your help.
?
Warren
?
|
Re: Reinstall G1 software
Totally agree with Paul. ? Put in a new battery, reset the Gemini power off and put in all Gemini 1 info, ?via Gemini ASCOM or by HC. ? ?Shut it down and re-boot it should be ok from there! ?
?
Generally most G1 ¡°oddball issues ¡° are caused by corrupt data by low battery. ? The vast majority. ? But!
?
You did mention HC going blank and unresponsive. ?There is quite a few instances that can cause this (in most likely order): a bad CPU; SRAM Bad; EEPROM data corrupt a bad EEPROM. ?
?
But, we will worry about this if the battery doesn¡¯t fix the issue.?
cheers
?
?
Brendan
|
Re: Reinstall G1 software
The very first thing to check is to turn off Gemini, open it, take out the 3v battery, leave it out for a minute or two, then replace it with a fresh battery. I'd also check the HC cable and connectors, to make sure there's no break or intermittent contact. There's also a possibility that the F2 fuse is going bad, which has happened to many Gemini-1 units and can be diagnosed and repaired fairly easily:
?
If that doesn't help, you may want to program (or get an already programmed) EPROM chip with Gemini firmware and then swap it with the one that's installed. Beyond that, you may want to contact one of our independent repairers for help and troubleshooting:
?
Regards,
?
? -Paul?
?
?
On Thu, Mar 13, 2025 at 11:22 AM, David Pitre wrote:
My Gemini 1 Is not working.?
I could get it to boot, start, and initially slew, but then the screen goes blank and is unresponsive.
Same thing with different hand controllers used.?
Then recently another problem started.
After starting and going to an object search, the screen allows to enter the object, identify its ?location, but then, with another press of the button, it just goes back to object search.
It also has stopped tracking. Solar tracking is enabled (I just use this amount on the sun). And I could Move the telescope with a hand controller, but the mount does did not track.
I am wondering if my software is corrupted.
Is there a way to reinstall it?
|
My Gemini 1 Is not working.?
I could get it to boot, start, and initially slew, but then the screen goes blank and is unresponsive.
Same thing with different hand controllers used.?
Then recently another problem started.
After starting and going to an object search, the screen allows to enter the object, identify its ?location, but then, with another press of the button, it just goes back to object search.
It also has stopped tracking. Solar tracking is enabled (I just use this amount on the sun). And I could Move the telescope with a hand controller, but the mount does did not track.
I am wondering if my software is corrupted.
Is there a way to reinstall it?
|
Re: Testing G1 encoder port
Hi there,
Look at the following URLs:
On Wed, Mar 12, 2025 at 5:40?PM David C. Partridge via <david.partridge= [email protected]> wrote:
I don¡¯t believe there are any high precision encoders that are compatible with the Gemini system, but I could be wrong.??? ? I was looking at the Renishaw high precision absolute encoders but Scott wasn¡¯t prepared to contemplate a solution that would cost around USD1400 per axis for him to purchase (so probably adding at least USD2000 per axis on the sale price).????? They¡¯d also need an extra board/box to decode the signal format they use to something that the Gemini could use.?? ??I believe that these are what the super expensive mounts like 10-Micron or AP offer as a (costly) option. ? Astro Devices sell some medium resolution relative encoders that provide about 4 arc-second resolution (311296 steps per revolution), but I don¡¯t know if they are compatible with the Gemini system ¨C I think they intend them to be used with their own Nexus DSC Pro (digital setting circle) product.?? If you do want axis encoders it may be worth asking them. ? David ? ? I'm curious to know more about the encoder port use. Is the intended use to add an external encoder to improve RA or DEC guiding? If this is correct, are there any products available to support high precision encoding?
|
Re: Help troubleshooting after replacing Gemini 1 internal bettery
Replacing the battery is pretty simple and after doing so you just need to re-enter your customisations (location, time etc.). ? David ?
toggle quoted message
Show quoted text
From: [email protected] <[email protected]> On Behalf Of Franco Meconi via groups.io
Sent: 12 March 2025 16:25
To: [email protected]
Subject: Re: [Gemini_users_io] Help troubleshooting after replacing Gemini 1 internal bettery? Hi Paul, thank you so much for your response. Fortunately I happen to have a spare Gemini 1, I tried using that one with the mount and the motors seem to be working OK, so the problem must be within the original Gemini 1 on which I did the battery replacement. Would love to know how to proceed though in order to get that gemini back running... Also I'm pretty terrified of replacing the battery on the spare Gemini (battery is definitely drained in that one)... ? As soon as I powered up the mount the RA motor started slewing at a very high speed, I had to almost immediately shut down the gemini to prevent the telescope from crashing into my pier. When I turned it back on the same thing happened, so I disconnected the motor cables from the Gemini and ran the setup using the hand controller (date and time, location, mount type, etc). I then switched it off, reconnected the motors and switched it back on for a warm restart, it seemed to be ok at first but as soon as I pressed one of the RA buttons on the hand controller the RA motor ran wild again at max speed, trying to slew west (I'm on the southern hemisphere, so that would be slewing east in the northern hemisphere, or lets just call it clockwise if you're behind the mount facing the celestial pole). When I tried to counter this slew with the hand controller it would show a MOTOR STALLED message on the hand controller. I tried replacing the battery again for the old one but the problem is still there.?
Hi Franco, and welcome to the group! Unfortunately, the uncontrolled slew or Stalled message indicates that Gemini has a problem reading servo encoders. This could be a problem with the motor cables, but more likely, a problem with the motor itself.
|
Re: Testing G1 encoder port
There¡¯s also the caveat that the support for shaft encoders may not be present in the Gemini-2 code.??? It was in the Gemini-1, but given how few of the Losmandy DSCH (their own shaft encoders) were sold, it¡¯s possible that the code for that isn¡¯t there in the Gemini-2. ? ¸é±ð²Ô¨¦, if you see this, could you clarify the situation? ? Thanks David ?
toggle quoted message
Show quoted text
From: [email protected] <[email protected]> On Behalf Of David C. Partridge via groups.io
Sent: 12 March 2025 16:40
To: [email protected]
Subject: Re: [Gemini_users_io] Testing G1 encoder port? I don¡¯t believe there are any high precision encoders that are compatible with the Gemini system, but I could be wrong.??? ? I was looking at the Renishaw high precision absolute encoders but Scott wasn¡¯t prepared to contemplate a solution that would cost around USD1400 per axis for him to purchase (so probably adding at least USD2000 per axis on the sale price).????? They¡¯d also need an extra board/box to decode the signal format they use to something that the Gemini could use.?? ??I believe that these are what the super expensive mounts like 10-Micron or AP offer as a (costly) option. ? Astro Devices sell some medium resolution relative encoders that provide about 4 arc-second resolution (311296 steps per revolution), but I don¡¯t know if they are compatible with the Gemini system ¨C I think they intend them to be used with their own Nexus DSC Pro (digital setting circle) product.?? If you do want axis encoders it may be worth asking them. ? David ? ? I'm curious to know more about the encoder port use. Is the intended use to add an external encoder to improve RA or DEC guiding? If this is correct, are there any products available to support high precision encoding?
|
Re: Testing G1 encoder port
I don¡¯t believe there are any high precision encoders that are compatible with the Gemini system, but I could be wrong.??? ? I was looking at the Renishaw high precision absolute encoders but Scott wasn¡¯t prepared to contemplate a solution that would cost around USD1400 per axis for him to purchase (so probably adding at least USD2000 per axis on the sale price).????? They¡¯d also need an extra board/box to decode the signal format they use to something that the Gemini could use.?? ??I believe that these are what the super expensive mounts like 10-Micron or AP offer as a (costly) option. ? Astro Devices sell some medium resolution relative encoders that provide about 4 arc-second resolution (311296 steps per revolution), but I don¡¯t know if they are compatible with the Gemini system ¨C I think they intend them to be used with their own Nexus DSC Pro (digital setting circle) product.?? If you do want axis encoders it may be worth asking them. ? David ?
toggle quoted message
Show quoted text
From: [email protected] <[email protected]> On Behalf Of jim.bachesta via groups.io
Sent: 12 March 2025 13:48
To: [email protected]
Subject: Re: [Gemini_users_io] Testing G1 encoder port? I'm curious to know more about the encoder port use. Is the intended use to add an external encoder to improve RA or DEC guiding? If this is correct, are there any products available to support high precision encoding?
|
Re: Help troubleshooting after replacing Gemini 1 internal bettery
On Wed, Mar 12, 2025 at 12:25 PM, Franco Meconi wrote:
Hi Paul, thank you so much for your response. Fortunately I happen to have a spare Gemini 1, I tried using that one with the mount and the motors seem to be working OK, so the problem must be within the original Gemini 1 on which I did the battery replacement. Would love to know how to proceed though in order to get that gemini back running... Also I'm pretty terrified of replacing the battery on the spare Gemini (battery is definitely drained in that one)...
?
That would mean that there's an issue with Gemini itself, possibly a connection issue from the DIN connector to the PCB, or with one of the servo controller chips. There are some repairers that work on Gemini-1 that might can further diagnose this and to repair, if necessary:
?
Contact one that's closest to you.
?
|
Re: Help troubleshooting after replacing Gemini 1 internal bettery
Hi Paul, thank you so much for your response. Fortunately I happen to have a spare Gemini 1, I tried using that one with the mount and the motors seem to be working OK, so the problem must be within the original Gemini 1 on which I did the battery replacement. Would love to know how to proceed though in order to get that gemini back running... Also I'm pretty terrified of replacing the battery on the spare Gemini (battery is definitely drained in that one)...
As soon as I powered up the mount the RA motor started slewing at a very high speed, I had to almost immediately shut down the gemini to prevent the telescope from crashing into my pier. When I turned it back on the same thing happened, so I disconnected the motor cables from the Gemini and ran the setup using the hand controller (date and time, location, mount type, etc). I then switched it off, reconnected the motors and switched it back on for a warm restart, it seemed to be ok at first but as soon as I pressed one of the RA buttons on the hand controller the RA motor ran wild again at max speed, trying to slew west (I'm on the southern hemisphere, so that would be slewing east in the northern hemisphere, or lets just call it clockwise if you're behind the mount facing the celestial pole). When I tried to counter this slew with the hand controller it would show a MOTOR STALLED message on the hand controller. I tried replacing the battery again for the old one but the problem is still there.?
?
Hi Franco, and welcome to the group! Unfortunately, the uncontrolled slew or Stalled message indicates that Gemini has a problem reading servo encoders. This could be a problem with the motor cables, but more likely, a problem with the motor itself.
?
?
Regards,
?
? ? -Paul
?
|
Re: Help troubleshooting after replacing Gemini 1 internal bettery
On Wed, Mar 12, 2025 at 11:24 AM, <francomeconi@...> wrote:
As soon as I powered up the mount the RA motor started slewing at a very high speed, I had to almost immediately shut down the gemini to prevent the telescope from crashing into my pier. When I turned it back on the same thing happened, so I disconnected the motor cables from the Gemini and ran the setup using the hand controller (date and time, location, mount type, etc). I then switched it off, reconnected the motors and switched it back on for a warm restart, it seemed to be ok at first but as soon as I pressed one of the RA buttons on the hand controller the RA motor ran wild again at max speed, trying to slew west (I'm on the southern hemisphere, so that would be slewing east in the northern hemisphere, or lets just call it clockwise if you're behind the mount facing the celestial pole). When I tried to counter this slew with the hand controller it would show a MOTOR STALLED message on the hand controller. I tried replacing the battery again for the old one but the problem is still there.?
?
Hi Franco, and welcome to the group! Unfortunately, the uncontrolled slew or Stalled message indicates that Gemini has a problem reading servo encoders. This could be a problem with the motor cables, but more likely, a problem with the motor itself.
?
?
Regards,
?
? ? -Paul
?
|
Help troubleshooting after replacing Gemini 1 internal bettery
Hi all! I'm new to the group. I recently bought a Losmandy G11 running on Gemini 1 v1.04 from a friend. I've been setting it up and trying to configure it with NINA. I'd been having issues with the automated meridian flip with NINA issuing multiple flip commands when I came across a forum post where someone with the same issue had resolved it by changing the internal CR 2354 battery on the Gemini 1, which I did because I had no idea how long it had been since it had been replaced, and here's where my problems started.
?
As soon as I powered up the mount the RA motor started slewing at a very high speed, I had to almost immediately shut down the gemini to prevent the telescope from crashing into my pier. When I turned it back on the same thing happened, so I disconnected the motor cables from the Gemini and ran the setup using the hand controller (date and time, location, mount type, etc). I then switched it off, reconnected the motors and switched it back on for a warm restart, it seemed to be ok at first but as soon as I pressed one of the RA buttons on the hand controller the RA motor ran wild again at max speed, trying to slew west (I'm on the southern hemisphere, so that would be slewing east in the northern hemisphere, or lets just call it clockwise if you're behind the mount facing the celestial pole). When I tried to counter this slew with the hand controller it would show a MOTOR STALLED message on the hand controller. I tried replacing the battery again for the old one but the problem is still there.?
?
Any help will be very appreciated!
?
Thanks,
?
Franco.?
|
Re: Testing G1 encoder port
I'm curious to know more about the encoder port use. Is the intended use to add an external encoder to improve RA or DEC guiding? If this is correct, are there any products available to support high precision encoding?
|
Re: Gemini is turning 25!
Hi Paul,
?
As one of first Losmandy mount users in Japan, I really enjoyed this article.
I recall I imported a CG-11 for my C11 in 1993.? The mount, which had 492 Digital Drive system, was initilaly used with NGC-max, and upgrade to the first Gemini GoTo system (Gemini-1).? Now it has OPW and SLW with Gemini-2, and is used for GSO-250RC or SVA-130EDT.? It is great that 30-year mount still works together with its upgrade.
?
I appreciate those who have contributed the development, and thanks for this invaluable community.
?
masami
|
Re: Gemini is turning 25!
|
Re: Gemini is turning 25!
Rene,/Paul/David have done a huge amount of great work and I applaud them. ? ?David completely re-wrote the Motor control dsPICC33 firmware, Paul has been constantly improving Gemini ASCOM and GFU (and more) and Rene¡¯, apart from developing the G2, constantly fixing small bugs rewriting ARM firmware lvl6, for encoder Quadrature sensing, and plethora of other improvements. ? The new using GPS 1PPS (yet to be released) takes the guiding and precision to another level.
Meanwhile have you ever noticed that most Gemini and Losmandy equipment is generally always backward support older equipment! ? ?This alone is to be applauded as it¡¯s giving a path for users to keep renewing their equipment to take advantage of more modern technology. ?
I purchased A G11/Gemini 1, many many years back because I could obtain every nut, bolt or part for it if needed. ?It¡¯s still running 100%.
?
I look forward to the future and many thanks to all
?
cheers?
--
Brendan
|
Hi All,
?
Please enjoy a brief history of the past quarter-century narrated by our own ¸é±ð²Ô¨¦:
?
Happy Birthday, Gemini!
?
? ?-Paul
|
Re: Testing G1 encoder port
toggle quoted message
Show quoted text
From: [email protected] <[email protected]> On Behalf Of Paul Kanevsky
Sent: 09 March 2025 17:57
To: [email protected]
Subject: Re: [Gemini_users_io] Testing G1 encoder port? You can use the ASCOM driver terminal window to get the encoder port status bits using command <312: You'll want to drive each of the encoder lines high (5v TTL) and then get the <312 status. Each line should result in a bit being flipped. I believe you'll need to enable the encoder port through the HC menus, first.
|
Gemini-1 SkySafari Wireless Control - WiFi or Bluetooth?
I have a 2008 G11 with Gemini-1 that I have been controlling with the SkyFi III wireless hotspot. Last time I used it, when I removed the micro USB charging cord, the USB female jack on the circuit board came off. While the module still works, I'll need to figure a way to attach the charging cord via another method. First challenge was getting the cover off the chassis. It was held on by 4 screws with tiny security type slots on top. None of the many security bits I had fit. Long-story short, I eventually got into the circuit board, only to find suitable solder points were lacking. I assume it has some sort of charging circuitry to disconnect charging power when the lithium battery is fully charged. So that is a challenge still to be met.
?
In the meantime I saw on this forum two possible substitutes for the SkyFi III, which is no longer available:
Both of these are described as working with mobile devices running?SkySafari. The quite modest price is about the same, from a Ukrainian vendor.
?
Which of these two would be the recommended solution?
?
Thanks,
Russ
?
?
|
Paul Kanevsky
Ma Ol
David C. Partridge