I have discovered a problem with my G2 system today that when I power on the system the switch light comes on from a few seconds and the goes out. At that point I turn off the power switch and check the power plug and find the fuse blown. I have tried this twice with the same results. I have removed the control box cover and inspected the circuit board front and back to see if I could see any problems visually but see nothing. I have two Identical systems so I have tried moving hand controllers and motor wiring to see if that made any difference, but nothing changed.?

Does anyone or has anyone had this type of issue and might offer some suggestion on what to look for or where to test for power??

Thank you for any assistance.?

Niel

Neil

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Do you have the 2nd 12V power out connector plugged in! ? If so remove this and power on. ?It could be an accessory on this line drawing too much current. ? Yes it has 2 fuses one for each line.?

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If not the power supply has 2 buck converters yo supply 5V and 3v. ?These have ?thermal/current overload. ?The SW LED is powered from 3V ?buck converter. ? One could be dead. ?It will get hot or be damaged.?

Or it’s a part (IC) on the Gemini pulling too much current the LED going out is the buck converter shutting down or a dead Buck converter but read on.?

As to what that part is….could be:

a)The buck converters;

b)A part downstream of the converters (an IC); or

c) or a bad H bridge or motor….something on the12v in line direct. B

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At boot the ARM commands the motors (via H bridge) to lock the motor rotors …..these are driven directly from 12v (or what ever power you use) in. ??

So remove the motors and pwr on! ? Does it still blow fuses?

If none of the above works or helps ….let it blow a fuse…..earth yourself on case (with lid off) touch top of ICs….feel for heat. ?

5A is a huge amount (at 12v it’s 60watts heat for that second or so)…… it will leave a heat trail or hot IC. ? Even for that small amount of time. ?Suffice to say….it can only be assessed or fixed by a or Losmandy.

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I do suspect a bad motor and or dead H bridge as this is direct power in, just past the reverse polarity protection diode. ?I have yet to see a buck converter go bad and blowing 5A fuse indicates a big short cct. ?If it’s a buck or IC it’ll have a burn mark or hole i it. ?Maybe take a few pictures and post them up

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Get back on this for more help

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cheers

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Brendan

Thak you for the information.?

There is not a second input attached.

I have bench tested the unit without the motors, so that is out.

I too suspect and IC or the H bridge. I have not checked the ICs for heat at this point. Is there any way to test the H bridge?

On sending back to Losmandy, I am not sure that they may have parts to repair this older unit so that is a concern too. I'll have to wait to give them a call next week and pose that question.?

One other thing is that this unit is in my observatory hard wired attached to Ethernet router and service computer. A few weeks ago there was a lighting strike near by that took out a bunch of my electronic equipment, Ethernet router to the Observatory and to the Gemin 2 unit, house router, IP supplier equipment and several power supplies. I am thinking that this may have damaged the Gemini system too.?

Any other though that might help would be appreciated.

Thank you for your input,

Niel?

Yes parts are available. ?But H bridge is a little tricky to R&R. ? The repairers have all parts. ?

But a pwr surge you can guarantee more than one IC part is damaged. ? But that’s the job of repairers to manage. ?I’ve repaired pwr surge that lost ARM, DsPIC33 and H bridge. ?I’ve seen ICs with large holes or a crater in them. ? ?All doable returned to service. ?

But of course the risk is a hidden burned track between PCB layers …unlikely but cannot be ruled out. ? All you can do is send for an assessment.?

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cheers

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Brendan

Brendan,

Great information. I don't see anything of that nature visible. So, I guess it will be heading off to Losmandy next week for repairs. Just fount a problem with my 50" TV set in the spare bedroom now that will not power up eighter. I can turn it on, and the indicator light comes on and slowly goes out, but the TV does not come on. Took it apart and did some voltage checks and the flow stops at a capacitor near and IC. So, I found a new board last night on Ebay, should be here next week.? I lost two main house routers in one week from these storms and the inline router in the observatory once too. In 30 years living here, I never had this much damage before. I will be starting to disconnect things that are not in use and when these bad storms come through.

Thank you for you help and direction,

Niel

A little off and on topic …it’s blown the switching PSU of the TV. ?A common issue.?

The Gemini also employs switching power supplies but of lower power. ?Sounds like a ground surge that’s the scourge of electronics.?

FWIW

Cheers

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Brendan

Brendan,

Yes, I am sure that what caused the problems. I just happened to be looking out the back door as the lighting struck the ground next to my fence. The bolt was about 2 feet in diameter and there was a ball of fire on the ground about 3 - 4 feet in diameter just rolling around. All was over in 10 - 15 seconds and is still burned in my mind. It all went down about 200 ft from the observatory too.??

Niel

Brendan,

I talked with Losmandy today and they seem to want to have the Gemini 2 just sent to you for repairs. How do I get your contact information to get it off to yopu?

Thanks,

Niel

I am in the US, Louisiana, so it might be most economical to send it to Michael. How do I get his contact information??

Thanks?

Niel