HEQ 5 Pro stop working OR "My stupid mistake"

[FenTaylor]

Hi all! Sorry for my English, I hope on this forum there is a place for my question. Because in the forums of my country I could not get an answer, and Google sent me here. I apologize to all who are unpleasant to read text with mistakes.

Yesterday the weather was good in my northern latitudes and I decided to test almost new HEQ 5 Pro. I installed the mount on a tripod, set up a polar star. Established a telescope, set up a balance. Above me were great stars, while I set everything up. 

The first thing I thought - do not reverse the polarity of the wires (+ and -) to homemade power cable for car battery (12 V). I thought about it so much that of course I confused everything... This is the most stupid mistake that could happen.

As soon as I saw the problem, I swapped the wires in places. The red power light was on, and I thought that everything would be fine. However, the control panel after the initialization attempt reported an error: "Both axes no response. You sailed, man". There was no last sentence, but my brain thought of it. By the way, the mount previously worked properly. This is not the first work with it.

There was hope that the problem with the power cable. I tried the standard cable for the car cigarette lighter socket and it did not work too. Above me were still great stars, while I dismantled my set.

I failed to check the connection via PC, because I do not have a suitable cable - there are no Serial Port on the PC. It will be difficult to find the owner of the same mount in my city, to understand what has broken - the motherboard or the control tube. Is it possible to see a malfunction when visually inspecting the motherboard? Can I test cheaper troubleshooting before I order a new motherboard in another country?

So, my action plan:

1. Convince my wife that all this is very cheap and it's okay that something is broken.
1. Check the connection of the mount to the computer (find the cable).
2. Disassemble the mount body, inspect the motherboard. Try to see something.
3. Find the owner of the same mount, find out what's broken - the motherboard or handset.

Or

1. Just order a new motherboard

Are there any other possibilities? I need tips. Thanks you!

P.S: If I respond to your messages, it means that my wife does not know yet and I am still alive.

Edited January 17, 2019 by FenTaylor

[Astro Imp]

Good morning and welcome to the forum.
I'm sorry to hear of your problems and am afraid I can't help but there are very knowledgeable members on the forum, I am sure one will help you.
Good luck.
By the way your post is easily understandable, no problems with your language skills.

[Cosmic Geoff]

It looks like the handset is still responding, so the problem is more likely to be in the mount.  The mount may incorporate 'reverse polarity protection' to guard against mistakes like yours.

I suggest you dismantle the mount and handset and look for components that have burnt, or a blown fuse.  Then, depending on your level of electronics skills, you can repair the sub-assembly or order a replacement board.

Typically, the handset checks with software for a response from each drive axis, and flags an error if it does not get one. This of course does not tell you what the problem is, and in the general case it could be anything - loose wire, corrupted software, blown components.   Or in your case, reverse polarity damage.

Update - you should search for "HEQ5 Reverse Polarity Protection."  Not good news, I think, but repairable.

[FenTaylor]

Hi guys! Thanks for replying to my post and tips. Of course, I will take care of reverse polarity protection after solving my problem.

I found the opportunity to check the connection HEQ5 to the computer. There was no connection and this means that the problem in the mount (not in handset) and need to deal with the board.

I tried to disassemble the mount and get the board and didn't see any damage. There was a smell of a new chip and nothing strange, but i found a similar problem that one astronomer diagnosed as a failed power inductor. Broken detail circled in blue on the photo. I don't know yet whether this will help me (although the symptoms are exactly the same), but maybe it will help someone else who faces a similar problem and finds this topic.

So... I don't have the skills of an electronics engineer, and it would seem that I need to order a motherboard and calm down. But three things push me to further research:

1. 130 euros for a new board.
2. 30 euro for its delivery
3. A few weeks of delivery waiting.

If it is appropriate, I will continue to write here about the results of the repair HEQ 5 after reversal polarity.

Edited January 19, 2019 by FenTaylor

[dunc]

I did this to my NEQ6, painful. That chip is a power regulator, I tried replacing it but didn't have a hot air soldering gun at the time, so gave in a bought a new board. You would think there would be a couple of diodes to help prevent this. External to the mount I use a power module from China to get 12v from a 19V laptop power brick and that has overcurrent and reverse polarity protection, it also has voltage and current metering, all for £8.99... Skywatcher should incorporate one in the mount!

[Stub Mandrel]

Hi Fen

Don't apologise for your English, it's far better than my attempts at other languages!

You aren't alone, I blew up a thermostat module recently by accidentally shorting the thermistor to +12V...

It is possible for voltage regulator chips to burn out without allowing the reverse voltage to reach the circuit so you may be lucky. It's worth seeing if you can find someone able to lift the chip with rework gun  (like a tiny hot air blower) and fit a replacement. They should be able to do this for 10-20 euros I would guess.

[Thalestris24]

I'm not certain, but I've seen pictures of the back of the pcb which suggest there is a voltage regulator on that side too.

Louise

[FenTaylor]

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.

Edited February 5, 2019 by FenTaylor

[FenTaylor]

In the hand tube, having traced where the 2 wires with the data from the mount go, I came across an obviously burnt-out, but unknown to me, microcircuit. Size 2x1.5mm, marking AF2 - I was searching, but I could not find what it is.

I traced the rest of the paths to where they lead, found out that the chip does not have power, and most likely it is a set of zener diodes to protect the 4 transmitted signals from overvoltage. I dismounted the chip with a Soldering Station and replaced it with 4 bridges - it turned out, the tube was able to send commands to the mount and receive the answer. 

In general, the tube and the mount board came to life.

Edited February 5, 2019 by FenTaylor

[FenTaylor]

It's a bit cool outside, so I wasn't sad while my mount was being repaired. Anyway, I could not use the telescope. ?

Edited February 5, 2019 by FenTaylor

[lux eterna]

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

 

Edited September 7, 2019 by lux eterna

[Stub Mandrel]

22 minutes ago, 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

 

Those power connectors are so badly designed, music effects pedals use them, I have a 'daisy chain' lead with multiple conectors, some are unused, which I have wrapped in insulation tape to prevent them shorting by accident.

[lux eterna]

I have two of these little evil dc plugs in my system, and I just created a home for each of them whenever I need to unplug them :

/Ragnar

[JamesF]

Hmmm.  I might have to have a think about this myself.

The fan in my 314L+ always runs when the power is connected, so I tend to unplug it and leave the connector dangling if I want the power on but I'm not using that camera at the time.  Perhaps that's not such a good idea.  Maybe I'll make up a new cable with an inline switch instead.

James

[JamesF]

I just noticed this in your signature, Ragnar: "HEQ5 Pro-AI (Arduino Inside)"

That sounds as though it might be interesting.  Have you posted about it at all?

James

[lux eterna]

Hi James,

A switch will be fine as long as you connect it to the plus cable.

The Arduino thing - you are the first to ask... It started over two years ago as a way to cure the HEQ5 Pro´s built-in non-linear movement of the RA motor during tracking (the motor rotation speed varies a little, with a 0.6 second cycle) . Then I added 2 x dslr intervalometer support. And then came the marriage between the Arduino and my NexGuide autoguider by emulating the NexGuider cable connected handpad so the NexGuide could be controlled by the same IR remote (from old dvd player) as the intervalometers etc. Then came dithering. Then I upgraded from IR control to radio ("HC-12 module") control and had two-way communication with provided for a cloud alarm (triggered by zero st-4 pulse activity from the NexGuider).  And somwhere along the road I moved most of the parts to a box outside the mount, so I need to change my signature to Arduino Outside - but how cool is that ?

I will try to describe this better in a separate post.

Ragnar

 

[kirkster501]

On 08/09/2019 at 12:48, JamesF said:

Hmmm.  I might have to have a think about this myself.

The fan in my 314L+ always runs when the power is connected, so I tend to unplug it and leave the connector dangling if I want the power on but I'm not using that camera at the time.  Perhaps that's not such a good idea.  Maybe I'll make up a new cable with an inline switch instead.

James

I don't follow?  If the power cable (coming from battery or a PSU to the camera or mount) is hanging, how can that effect your camera or - pertinent to this thread - the mount?  Sure youd short the PSU but not the mount?

What inline switch did you use please?  That is a good idea and I may do that too.

[JamesF]

9 hours ago, kirkster501 said:

What inline switch did you use please?  That is a good idea and I may do that too.

This is the one I bought.  I would have preferred a slightly smaller switch body, but couldn't find anything.  This one seems to do the job, anyhow, and means I can power down the camera without having to remove the plug.

https://www.ebay.co.uk/itm/223056209843

James

[kirkster501]

On 22/10/2019 at 18:43, JamesF said:

This is the one I bought.  I would have preferred a slightly smaller switch body, but couldn't find anything.  This one seems to do the job, anyhow, and means I can power down the camera without having to remove the plug.

https://www.ebay.co.uk/itm/223056209843

James

Thanks.  Ordered a couple.

[lux eterna]

On 22/10/2019 at 09:45, kirkster501 said:

I don't follow?  If the power cable (coming from battery or a PSU to the camera or mount) is hanging, how can that effect your camera or - pertinent to this thread - the mount?  Sure youd short the PSU but not the mount?

What inline switch did you use please?  That is a good idea and I may do that too.

A quick short cirquit, or just a bad connection (like disconnect-connect-disconnect etc ), can produce transient voltages greater than the power supply itself. This is likely to happen with inductive loads (like the stepper motors in a mount) and it becomes worse with longer power supply cables. These transients will reach all devices connected to the same supply.

Ragnar

 

[Stub Mandrel]

11 hours ago, lux eterna said:

A quick short cirquit, or just a bad connection (like disconnect-connect-disconnect etc ), can produce transient voltages greater than the power supply itself. This is likely to happen with inductive loads (like the stepper motors in a mount) and it becomes worse with longer power supply cables. These transients will reach all devices connected to the same supply.

Ragnar

 

Changing to a switch is  unlikely to elminate such transients. The mount should be designed to cope with such things.

[JamesF]

Though I'm much happier having a switch rather than pulling a live plug and leaving it dangling where I have no idea what it might come into contact with.

James

[stash_old]

No expert but wouldn't adding a large capacitor give the extra spike voltage some where to go ?   After all a switch itself causes a voltage spike doesn't it ,as does plugging in other devices?  As I say i am no way an expert!

[lux eterna]

I agree, a switch is a good thing. I was talking about a bad connection or a short cirquit, which can kill the electronics (if not designed for it - and the HEQ5 Pro motherboard is not).

A capacitor (or even better, a few of them with different capacity) as close as possible to the vulnerable electronics will help a bit, but it is still not 100% safe.  After my last nightmare, I have a 1 ohm resistor in my power distribution box with a switch in parallell with it. That switch is always open when I power up or down the main switch on the mount, and closed during operation.

Ragnar

[kirkster501]

6 hours ago, Stub Mandrel said:

Changing to a switch is  unlikely to elminate such transients. The mount should be designed to cope with such things.

Yes I agree.  I have a mount top fuse panel/distribution panel to feed the 12v from my PSU to the various pieces of gear fused at different amperage.  However, the fuses will blow due to over-current, not a transient spike in voltage.  So this is no protection.

As James also says, the switch at least eliminates a 12v 2.1mm plug hanging in mid-air, waiting to short in some crazy, unanticipated way or on a slew.  Remember the old adage; if it can go wrong, it will....

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.  So even though I am using a proper Farnell PSU, I am still thinking of  using a crowbar circuit across the 12v outputs, unless these PSU's already have such a thing in their design?

Edited October 31, 2019 by kirkster501