Re: Old Gemini Controller Motherboard
Yes they are dual Schottky diodes used to steer 5V around the PCB. ?Divides up pwr to CPU, HC, other ICs and motor encoder systems. Seen this type (actual) of fail before. ?But usually one fails not both.?
Im not at home atm but they can be replaced. ? Also need to check the buck converter and other system ICs post repair. ?It¡¯s possible it¡¯s a surge as a fail like this concerns many ICs....they cannot all be bad. It¡¯ll need a little work to clean up burns and some PCB holes around there are thru hole but. ¡°yes¡± it can be repaired.?
Edit:
just saw what looks like burn marks on the buck converter IC. ?HMMMM look if that¡¯s blown yes it can be replaced and I have spare ICs but there is a possibility of it causing a surge damaging many 5V ICs. ?
I have a spare PCB of that type that¡¯s good working condition and tested ok. ?However either of the repairers can probably do it. ? They also need to check your motors (encoder) and HC....
--
Brendan
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Re: Old Gemini Controller Motherboard
Currently it boots if no battery for CMOS is present
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Re: Old Gemini Controller Motherboard
Hi Ansuman
there are 3 repairers:
Michael Herman in USA;
David Partridge n UK; and me?
Brendan in Australia
There maybe others but it¡¯s known these have parts resources knowledge etc for all PCB repairs. Contact by posts or messages?
The RJ connector PCBs are still good units. ?Some required a mod to extend battery life. ?I assume battery is ok is just it won¡¯t boot! ?Another common issue is the fuse F2 on units which the RJ PCB doesn¡¯t have...it tends to burn out small diodes instead.?
Thus if it¡¯s not booting does the system display any beeps codes dots on handset or does the handset led (below the buttons) come on?
Can you post a picture of the resistor!
--
Brendan
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Old Gemini Controller Motherboard
Looking for some pointers on how to go about fixing my G11 Gemini 1 Controller with RJ cables and not round connectors.
?
I have been using this mount for almost forever though considered myself as second owner for over 12 years. The controller hasn¡¯t been perfect for past one year or so with CMOS battery. Every time I put a new battery it will stop booting so for some time now I have been using my laptop to load location and other settings via serial port and recently that also stopped working.
Upon inspection discovered a dead spider inside and a burnt resistor. Question is if the old motherboard is salvageable and who can fix or shall I start look for an upgrade?
Any suggestions will be appreciated. Thank you, Ansuman.
?
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Re: Screws on the CG-11... Saddle plate bolts.
If you cannot get these (1/4-20 thread, US sized threads, stainless steel), send me your mailing?address, and I think I have some that can get you out a package of a few different lengths.??
If you are overseas from the US, International shipping costs are always the most horrific part of this hobby... though somehow China post found a way to make these a bargain.??
If interested, send me your mailing address and I'll get a package out to you. It will be much cheaper and easier if you can buy them where you live.??
The ones I have are 18-8 type stainless steel, and with a hack saw and file, (and a vice!) you can cut and file down the ends to the length you need.??
I have these thread lengths: 1+1/8 (1.125 inch), 1+3/8 (1.375 inch), and 1+3/4 (1.75 inch) at home.??
The saddle into which you bolt these is quite shallow (on the GM8 anyways) so the length has to pretty close to get them in.? Again, I sometimes must cut and file the ends to fit correctly.
Best, Michael
Hi Michael,
Thanks for the photos. Indeed, I need longer bolts. I want to replace the original saddle and the replacement saddle is thicker. The threaded part of my original bolts seems to be approx. 12mm long. So, judging from your pictures, your bolts are longer. I guess 15-18mm or so should be fine. I tried to convert the diameter to inches, but is it 39/128 or 19/64 or..
I am from Munich, Germany btw.
Thanks
Stephan
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Re: GM811G--pier extension or RA extension?
Jmyers1951,
These two parts were designed to do different things. The RA extension was designed to let the saddle clamp clear the servo motors when used with the newer tucked motor configuration and to extend the time before needing to do a meridian flip. If you have a tucked motor mount the RA extension allows 360 degrees of rotation on RA and DEC.?
A pier extension is designed to raise the mount for better placement for standing or tall visual observers and to increase the time available before needing to flip and reduce the chances of a tripod leg strike by a telescope with long overhangs.?
For best results you will find you need both upgrades to maximize the time shooting through the meridian and to reduce the chances of a let strike. When used in combination with the safety limts set specifically for your longer tube you can maximize you time on target before meridian flip and totally eliminate leg strikes.?
Of course you also may want to consider the need to tuck the motors for the absolute maximum freedom of movement of the G11 head. The improvement is significant but maybe you don't need or want it.
--
Chip Louie - Chief Daydreamer Imagination Hardware
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Regarding the screws on top of the C11, I had a similar problem with my C11 EdgeHD as I wanted to mount a bar. The screws on the rear towards the mirror were long enough (there are 6 of them with the same thread, but of different length, so try removing all of them and choose the longest, the others are fine for the finder mount). The ones on the front towards the corrector plate were too short and had a different thread compared to the ones on the rear; I bought some M5 screws, and they fit not perfectly but good enough (I had to force them a little bit). The original screws go perfectly inside an M5 threaded hole, so I guess they are really M5, but the screws I bought were slightly larger by a couple of hundred microns. Others confirmed me that Celestron is using metric screws. By the way, the screws I bought were really too long, so I had to cut them to the needed length. Be careful if you have to cut them because the thread may be slightly damaged where you cut; before cutting, screw a nut inside, and after cutting unscrew and screw it again several time to restore a good thread.
Ciao, Claudio.
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Re: On the subject of ... R4ZZ bearings for improved PE...
Any bearing can give issues. ? We used to clean and re-grease miniature bearings for F111 instruments. ? I¡¯ve forgotten most ?I used to know about them we had a huge bearing bible book.?
I wouldn¡¯t worry about load a balanced mount inertia isn¡¯t that high. I wonder if a tapered needle bearing would suit....but I doubt you can get one to fit and it would have a very small sweet spot of correct loading, axial play, and worm mesh.
?These are the issues with the current worm & bearings. ?I think an excellent job with the bearings and Belleville washers. ? Great idea
--
Brendan
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Hi Michael,
Thanks for the photos. Indeed, I need longer bolts. I want to replace the original saddle and the replacement saddle is thicker. The threaded part of my original bolts seems to be approx. 12mm long. So, judging from your pictures, your bolts are longer. I guess 15-18mm or so should be fine. I tried to convert the diameter to inches, but is it 39/128 or 19/64 or..
I am from Munich, Germany btw.
Thanks
Stephan
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Re: On the subject of ... R4ZZ bearings for improved PE...
Jim:
As far as I've heard, none of the recent modifications that Losmandy has done (new OPW, tucked gearbox, spring-loaded worm) actually improve performance (they address other concerns).? My experience is that the new OPW worm has increased PE, but again with guided imaging I think PE is not the appropriate quality metric.? So if any of the modifications you mentioned improve RA performance (and this is not a given, though some have had some success) then they should apply to your mount as well.
Keith
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Re: On the subject of ... R4ZZ bearings for improved PE...
Do these?new bearings, Belleville washers and clutch disks improve the RA performance?of mounts that are about 14 month old?? I got my GM811G mount just before they migrated to the Spring Loaded Worms.? I sent the mount back in to have the DEC axis modified later.
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Re: On the subject of ... R4ZZ bearings for improved PE...
Lastly ...
This note accompanied my sales order receipt just now.? At least they should listen to customer complaints!
--------
Regards,Teddyteddy@...The Boca Bearing Company GuarantyWe stand behind our product 100% and we always strive to provide a satisfaction guaranteed service. If you do, however, have any questions or problems please feel free to contact us directly at the information below, or by replying to this email. Thanks again for using Boca Bearing Company; we look forward to working with you again in the future.
On Tue, Sep 17, 2019, 10:20 PM Michael Herman via Groups.Io <mherman346= [email protected]> wrote: Glad you discovered the trouble in your system (was a bad bearing) and fixed it.? I agree with your comments that in general we have to rotate the center of these R4ZZ bearings by hand and exclude ones that feel rough under rotation.??
However I have not found any of the ABEC7 ones I previously got from Boca to be defective.? I found them to be quite tight with respect to center axis compared to ones of lesser quality. That is, the new ones had almost no ability to accommodate an axial tilt up the center. My prior experience does not mean you can't ever get a bad one from them.??
I always hand test bearings to prevent a bad one from affecting the RA behavior.? I only select the smoothest ones from my stock for the RA worm.??
It was Michael Sinescalchi's report that he found bearings to be a source of trouble a long while back, that pointed to the need for testing them.? If you look at , or other websites, you discover a range of manufacturers and quality levels and prices.? We hope the highest rated ones really are better, but ... who knows.??
Best of luck, Michael
?
On Tue, Sep 17, 2019, 8:07 PM Les Niles < les@...> wrote:
Interesting... the ABEC scale, I'm learning, is really about the
dimensional tolerances of the bearing.? From the :
"The ABEC
rating does not specify many critical factors, such as load
handling capabilities, ball precision, materials, material
Rockwell hardness, degree of ball and raceway polishing,
noise, vibration, and lubricant."? So
there's plenty of room for an ABEC7 to be rougher turning than an
ABEC5.
-Les
On 9/17/19 11:02, Keith N wrote:
[Edited Message Follows]
Funny you should bring up the subject of bearings.? I've been
wrestling with my older G11 for some time now and was (or maybe
still am) on the edge of moving on from this mount as the hobby
has become the mount.? I'm no longer trying to tame the large PE
(10" peak to peak with OPW that nothing I try seems to reduce)
since this is not what affects guided imaging, but instead have
been trying to get rid of very noisy tracking - rapid RA changes
on the order of 1.5-2" over a few seconds that guiding can't keep
up with.? I tried Belleville, different high-precision worm,
McLennan gearboxes, etc, etc, etc.
Well finally last evening I tracked this down to the new (repeat
NEW) ABEC7 bearings from Boca I had installed some time back.?
When I removed the worm and rotated it while holding on to the
bearings, I could feel they were not as smooth as both the ABEC5 I
had on hand (can't recall vendor) or the stock Losmandy bearings
that came with the OPW.? Sure enough last night I finally tested
on the scope and the tracking is much more well behaved after
putting in the ABEC5.
So takeaway is that ABEC7 in and of itself does not mean better.?
I could have just a bad sample (replaced both though probably only
one was bad).? So best to probably order many and cherry pick the
good ones.
Keith
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Re: On the subject of ... R4ZZ bearings for improved PE...
Glad you discovered the trouble in your system (was a bad bearing) and fixed it.? I agree with your comments that in general we have to rotate the center of these R4ZZ bearings by hand and exclude ones that feel rough under rotation.??
However I have not found any of the ABEC7 ones I previously got from Boca to be defective.? I found them to be quite tight with respect to center axis compared to ones of lesser quality. That is, the new ones had almost no ability to accommodate an axial tilt up the center. My prior experience does not mean you can't ever get a bad one from them.??
I always hand test bearings to prevent a bad one from affecting the RA behavior.? I only select the smoothest ones from my stock for the RA worm.??
It was Michael Sinescalchi's report that he found bearings to be a source of trouble a long while back, that pointed to the need for testing them.? If you look at , or other websites, you discover a range of manufacturers and quality levels and prices.? We hope the highest rated ones really are better, but ... who knows.??
Best of luck, Michael
?
On Tue, Sep 17, 2019, 8:07 PM Les Niles < les@...> wrote:
Interesting... the ABEC scale, I'm learning, is really about the
dimensional tolerances of the bearing.? From the :
"The ABEC
rating does not specify many critical factors, such as load
handling capabilities, ball precision, materials, material
Rockwell hardness, degree of ball and raceway polishing,
noise, vibration, and lubricant."? So
there's plenty of room for an ABEC7 to be rougher turning than an
ABEC5.
-Les
On 9/17/19 11:02, Keith N wrote:
[Edited Message Follows]
Funny you should bring up the subject of bearings.? I've been
wrestling with my older G11 for some time now and was (or maybe
still am) on the edge of moving on from this mount as the hobby
has become the mount.? I'm no longer trying to tame the large PE
(10" peak to peak with OPW that nothing I try seems to reduce)
since this is not what affects guided imaging, but instead have
been trying to get rid of very noisy tracking - rapid RA changes
on the order of 1.5-2" over a few seconds that guiding can't keep
up with.? I tried Belleville, different high-precision worm,
McLennan gearboxes, etc, etc, etc.
Well finally last evening I tracked this down to the new (repeat
NEW) ABEC7 bearings from Boca I had installed some time back.?
When I removed the worm and rotated it while holding on to the
bearings, I could feel they were not as smooth as both the ABEC5 I
had on hand (can't recall vendor) or the stock Losmandy bearings
that came with the OPW.? Sure enough last night I finally tested
on the scope and the tracking is much more well behaved after
putting in the ABEC5.
So takeaway is that ABEC7 in and of itself does not mean better.?
I could have just a bad sample (replaced both though probably only
one was bad).? So best to probably order many and cherry pick the
good ones.
Keith
|
Re: On the subject of ... R4ZZ bearings for improved PE...
Interesting... the ABEC scale, I'm learning, is really about the
dimensional tolerances of the bearing.? From the :
"The ABEC
rating does not specify many critical factors, such as load
handling capabilities, ball precision, materials, material
Rockwell hardness, degree of ball and raceway polishing,
noise, vibration, and lubricant."? So
there's plenty of room for an ABEC7 to be rougher turning than an
ABEC5.
-Les
On 9/17/19 11:02, Keith N wrote:
toggle quoted message
Show quoted text
[Edited Message Follows]
Funny you should bring up the subject of bearings.? I've been
wrestling with my older G11 for some time now and was (or maybe
still am) on the edge of moving on from this mount as the hobby
has become the mount.? I'm no longer trying to tame the large PE
(10" peak to peak with OPW that nothing I try seems to reduce)
since this is not what affects guided imaging, but instead have
been trying to get rid of very noisy tracking - rapid RA changes
on the order of 1.5-2" over a few seconds that guiding can't keep
up with.? I tried Belleville, different high-precision worm,
McLennan gearboxes, etc, etc, etc.
Well finally last evening I tracked this down to the new (repeat
NEW) ABEC7 bearings from Boca I had installed some time back.?
When I removed the worm and rotated it while holding on to the
bearings, I could feel they were not as smooth as both the ABEC5 I
had on hand (can't recall vendor) or the stock Losmandy bearings
that came with the OPW.? Sure enough last night I finally tested
on the scope and the tracking is much more well behaved after
putting in the ABEC5.
So takeaway is that ABEC7 in and of itself does not mean better.?
I could have just a bad sample (replaced both though probably only
one was bad).? So best to probably order many and cherry pick the
good ones.
Keith
|
Do you need longer bolts?? If so, how long a threaded part do you need?? Here are photos of the saddle bolts on a GM8.??
(I'll check on the bolt type on my GM8 when I get home.? I think they are the same for G11 as for GM8 saddle.... )
And...where in Earth are you located?
Best, Michael
Dear Group members,
I own a Celestron 11 with a Losmandy G11 mount. Now I want to replace the saddle plate and add an accessory bar on top of the C11. However, coming from the metric part of the world, I can't figure out what screws to buy. Can you help me with that please? I need to know what kind of screws hold the saddle plate and what kind of screws are on top of the C11 for mounting an accessory bar.
Thank you in advance
Stephan
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Dear Group members,
I own a Celestron 11 with a Losmandy G11 mount. Now I want to replace the saddle plate and add an accessory bar on top of the C11. However, coming from the metric part of the world, I can't figure out what screws to buy. Can you help me with that please? I need to know what kind of screws hold the saddle plate and what kind of screws are on top of the C11 for mounting an accessory bar.
Thank you in advance
Stephan
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Re: On the subject of ... R4ZZ bearings for improved PE...
Yikes, Keith. Not a fun story to read but recently, other owners have been having trouble.? If you are in my area, or want me to try a repair of your system,?let me know.? At least I can try to determine and remedy the cause.? Or..as you say... move up the mount food chain to a higher level mount.? It's just a matter of money...!
Very best, Michael
[Edited Message Follows]
Funny you should bring up the subject of bearings.? I've been wrestling with my older G11 for some time now and was (or maybe still am) on the edge of moving on from this mount as the hobby has become the mount.? I'm no longer trying to tame the large PE (10" peak to peak with OPW that nothing I try seems to reduce) since this is not what affects guided imaging, but instead have been trying to get rid of very noisy tracking - rapid RA changes on the order of 1.5-2" over a few seconds that guiding can't keep up with.? I tried Belleville, different high-precision worm, McLennan gearboxes, etc, etc, etc.
Well finally last evening I tracked this down to the new (repeat NEW) ABEC7 bearings from Boca I had installed some time back.? When I removed the worm and rotated it while holding on to the bearings, I could feel they were not as smooth as both the ABEC5 I had on hand (can't recall vendor) or the stock Losmandy bearings that came with the OPW.? Sure enough last night I finally tested on the scope and the tracking is much more well behaved after putting in the ABEC5.
So takeaway is that ABEC7 in and of itself does not mean better.? I could have just a bad sample (replaced both though probably only one was bad).? So best to probably order many and cherry pick the good ones.
Keith
|
Re: On the subject of ... R4ZZ bearings for improved PE...
Funny you should bring up the subject of bearings.? I've been wrestling with my older G11 for some time now and was (or maybe still am) on the edge of moving on from this mount as the hobby has become the mount.? I'm no longer trying to tame the large PE (10" peak to peak with OPW that nothing I try seems to reduce) since this is not what affects guided imaging, but instead have been trying to get rid of very noisy tracking - rapid RA changes on the order of 1.5-2" over a few seconds that guiding can't keep up with.? I tried Belleville, different high-precision worm, McLennan gearboxes, etc, etc, etc.
Well finally last evening I tracked this down to the new (repeat NEW) ABEC7 bearings from Boca I had installed some time back.? When I removed the worm and rotated it while holding on to the bearings, I could feel they were not as smooth as both the ABEC5 I had on hand (can't recall vendor) or the stock Losmandy bearings that came with the OPW.? Sure enough last night I finally tested on the scope and the tracking is much more well behaved after putting in the ABEC5.
So takeaway is that ABEC7 in and of itself does not mean better.? I could have just a bad sample (replaced both though probably only one was bad).? So best to probably order many and cherry pick the good ones.
Keith
|
On the subject of ... R4ZZ bearings for improved PE...
Hi?gang,
I have a fellow Losmandy user in Australia, interested in having me send some R4ZZ ABEC-7 bearings to him with some Belleville washers, and clutch disks.? So I am putting together a kit for him.
I looked for my favorite vendor of the R4ZZ ABEC-7 bearings, namely .? I specified those when I wrote the PDF on installing these, a few years ago.? Since then, other people mentioned the good price on these quality bearings from McMaster-Carr online.??
I remember seeing the same item, some time ago, on McMaster-Carr website for about $5.50.
At BocaBearings, they show these bearings at a cost (singles) of ~$10.77 each.? At quantity 10, they go down slightly to $9.39.? The specific bearing is listed here: ??
I then chatted with the seller BocaBearings.com. I told him the McMaster-carr version were only about $5.50.? He replied that his bearings are more costly than McMaster because they are stainless steel, and that the McMaster-Carr bearings are not stainless.? (I guess he's in the bearing business and should know!)
So...? this might explain the 2X price difference between these 2 vendors.? And of course, we have our equipment outdoors, where heat and moisture can corrode things, so the stainless?steel bearings would be preferred for long term use.
----------- I just put in my order for 10 of these from Bocabearings.? ?I'll have a few spare, so let me know if you also want some, and I'll order more of them... but of course you can get them directly for hardly any more money!? They are harder to get abroad, so if you are out of the US, let me know if you want me to ship you some for upgrading your mount also.
All the best, Michael
--
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Sounds like I started off with bad advice before coming here. What I want to do is control the mount with my laptop which for now I have stellarium on it. I may try skysafari to see which I like better. It's all new to me. I just got this mount a few weeks ago and because of bad weather on North Carolina's coast ( I'm a 60 yr old lineman) I haven't had much time to set it up. My only other mount was a meade dc drive starfinder 8". Using a program on the laptop I'm hoping will help me navigate and learn the sky better for using the gemini hand control. Plus I have a young great nephew that is interested.? So your instructions sound much simpler.? Thanks. I'm not setting my scope up because I am on call at work. I've been out multiple times today. I'll try this next week. My understanding was that I had to configure the tp-link before connecting it to the mount. So that is what I have been doing along with fussing! Lol thanks.
Greg
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Michael Herman
Chip Louie
Greg