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HEQ 5 Pro stop working OR "My stupid mistake"


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3 hours ago, kirkster501 said:

...This is actually one of the main reasons I like big batteries.  There is no way the battery can output a spike above 12.8v, whereas a PSU, if on its way out and cream-crackered, can...

With inductive loads (like the stepper motors in a mount), voltage spikes are generated from the current transients that happens when you break the current feed, no matter if it is a battery or a PSU. 50 volts in a 12 volt system is quite possible. If you switch off the mount power switch, there will be one (very fast) voltage spike at the battery side of the switch (which should do no harm). But if you fiddle with a power connection with the mount turned on, there will be multiple spikes that can reach the mount electronics (and other equipment as well).

But I agree that a battery is still safer than a PSU. The battery itself will never be to blame.

Ragnar

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  • 5 months later...
On 05/02/2019 at 17:43, FenTaylor said:

Thanks to everyone who answered this topic.

It seems my problem is solved without buying a new motherboard. Unfortunately, I have little knowledge of electronics and could not solve the problem myself. But any master who has electronic skills is able to check which item has failed and repair (or replace) it. I found such a master, it was not difficult for him to repair the board.

I'll write that need to be repaired (in my case) to help those who have the same problem. Then I write on behalf of a friend.

Suspicions were confirmed. Broke inductor on the board. If more precisely - оne winding broke and both windings from the side of the board caused short circuits to each other. The photograph from the microscope shows in more detail how one wire melted and broke, and melted the enamel of the neighboring winding and made a short circuit with it.

The inductor has been replaced with a resettable fuse (2A) and the motherboard is resurrected, but the board still did not work with my hand control tube (the test showed that it works with others). It became clear that the hand tube is also broken.

heq5.JPG

heq5-2.jpg

Thankyou! You just saved me having to buy a new board! I've replaced the inductor with two bits of wire for now and my mount is back in to life :D  I wasn't sure it was going to work but glad to report it does! Will add a resettable fuse later when the world is more back to normal!

It's a bit late now to set up and get some images though I was tempted to pull the gear out and do so! 

 

Once again- Thanks! 

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  • 7 months later...
On 22/04/2020 at 03:39, jiberjaber said:

Thankyou! You just saved me having to buy a new board! I've replaced the inductor with two bits of wire for now and my mount is back in to life :D  I wasn't sure it was going to work but glad to report it does! Will add a resettable fuse later when the world is more back to normal!

It's a bit late now to set up and get some images though I was tempted to pull the gear out and do so! 

 

Once again- Thanks! 

So good to see you managed to get it repaired, someone told me this hobby has some big learning curves,looks like you have got the first one over G old luck and clear skies. Lum.

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  • 1 month later...

On the power supply side, the inductor and or the two smoothing capacitors below J1 connector often pop.  Replacing the inductor with a resettable 2A fuse can resolve that issue, as does replacing the two capacitors. 

When it comes to a mount that has power but the handset is displaying "no response both axis" this indicates that the two PIC microcontrollers have been blown.  It is possible to replace them, but you also need to convert the downloadable firmware file to a HEX format and then reprogram two new blank 16F886's.  It's doable (I've repaired 5 goto dobsonian's with MC004 / 3 boards this way) but you need access to a PIC programmer in order to do so

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  • 4 months later...
On 07/09/2019 at 16:14, lux eterna said:

FenTaylor, I wish I could buy you a beer !

Tonight I had the same nightmare - "Both Axes no response". I followed your excellent guide and found the same faulty (dual) inductor. I had nothing to replace it with so I just snapped it off and made two solder bridges where it was sitting, and now the board has come back to life ! The handset was not affected, just the motherboard. Thanks a lot mate, you saved me both money and time under the stars !

In my case, the reason for the breakdown was a 12V connection (intended for my NexGuide autoguider) that was unused for the moment and just hanging from the mount. The center part is +12V and it is not very well protected, so of course it would touch some grounded metal and that was it.

/Ragnar

 

On 21/04/2020 at 21:39, jiberjaber said:

Thankyou! You just saved me having to buy a new board! I've replaced the inductor with two bits of wire for now and my mount is back in to life :D  I wasn't sure it was going to work but glad to report it does! Will add a resettable fuse later when the world is more back to normal!

It's a bit late now to set up and get some images though I was tempted to pull the gear out and do so! 

 

Once again- Thanks! 

Thanks for the feedback guys. I'm glad the topic was helpful 🙂 

After that incident, there was no problem with this mount and I spent many great nights under the stars.

1581537601126313799.jpg

Edited by FenTaylor
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