Skywatcher HEQ5 Pro New Mainboard?

[TinyGravitas]

So, first up, a TL;DR: I bought a new mainboard for my HEQ5 Pro after it blew. And the board that arrived doesn't look ANYTHING like any other board I've seen for the HEQ5 Pro.

Now the long version. 

In the early part of the week I was running some tests with some new equipment and everything was going great. Right up until the point where I was slewing to M31 and suddenly everything connected to my laptop disconnected for a few moments. My camera came back up, but the mount did not. After some investigation with swapping from my EQDIRECT lead to the handset and back a few times it seemed to be terminal. I disassembled my head and pulled out my mainboard, I then ran through with some advice about changing the two 470uF caps on there which I did and still nothing. So it's proper fried. I discovered the culprit in the end. I had a series of flying leads on the new power supply I bought and it turns out the positive centre of the 12V connectors sit slightly proud so I'm theorising that it touched with the legs of the telescope or with the negative of one of the flying leads and caused a short that blew the board.

So I decided to order a new mainboard:

https://www.microglobe.co.uk/sky-watcher-motherboard-for-heq5-pro-p-15281.html

Whilst that was coming I built myself a little power distrubution box to avoid this happening in future, something would have to go REALLY wrong for something to make a bad connection now.

And so today the board arrived. Except it's not like any other HEQ Pro board I've ever seen. And it's nothing like the picture on their website. I also can't find the board anywhere online.

So here below you can see the old Synscan Rev2 board I blew up and took out, ignore the two poorly soldered Caps in the bottom right.

And here you can see the new board that was shipped to me today.

 

The weird thing is that everything that should be there, is there. They have swapped out the controllers and moved a lot of the components from the back to the front, but there appears to be everything here, plus some extra? They have swapped the PIC micros out for that ARM up at the top, and it's all a little bizare. 

No matter how much I search for this board I can't find any details on it and I'm wondering if it's some kind of knockoff?

Anyway, I don't have much to lose by trying it out. I doubt it could do much damage to my steppers or my hookup board so really it only risks blowing itself. 

So I'll plug it in later and see what I get? 

I'll be sure to make sure that the hand controller portion of it is only putting out 12v and only down the correct pins, but who knows? 

At least the board is more compact.

[TinyGravitas]

So for anyone waiting on the answer for this with bated breath! 

The answer is YES!

The board does appear to work, and does appear to mimic things pretty precisely. The replacement was straight forward and pretty easy to handle, the connectors actually feel stronger and more secure than the original board I pulled out.

The steppers definitely seem to have a slightly different tone to them but other than that it works fine. 

I haven't done any observations with this yet, but I'll report my findings back into this thread the next clear night I get.

There's another advantage with this board, which is the price, as it comes in at a little over £100 instead of the nearly £150 you sometimes end up paying for the older skywatcher board.

If anyone comes across this thread who has a new skywatcher I would be intrigued to find out if this board is a knockoff, or just a newer style board that Skywatcher are now using for their EQ5 Mounts.

[MarkAR]

Looks like a completely revised board. The new one has REV C at the bottom left, they must finally have had enough of the blown boards to do something new. Looks like it came out in 2019 so it could be being fitted to newer models already, potential blown boards make things hard to sell.

[TinyGravitas]

8 hours ago, MarkAR said:

Looks like a completely revised board. The new one has REV C at the bottom left, they must finally have had enough of the blown boards to do something new. Looks like it came out in 2019 so it could be being fitted to newer models already, potential blown boards make things hard to sell.

That was my thought too. I think it also represents a reduction in costs for them. The chips on the new board are much more modern, faster and extremely cheap. They are using the stm32 arm chip which is the same one OnStep uses. They are cheap as chips and relatively reliable. 
 

Plus the board is single sided which will also help to reduce costs. I’m very curious to see if we will start seeing this board in newly bought scopes in the coming months. The only weird thing for me is the lack of Skywatcher or Synscan branding on it.

[MarkAR]

18 minutes ago, TinyGravitas said:

Skywatcher or Synscan branding on it.

Outsourced or design rights probably. I think I've seen SCHMIDT on other boards.

Edited September 16, 2020 by MarkAR

[platesolver_com]

On 15/09/2020 at 15:08, TinyGravitas said:

So, first up, a TL;DR: I bought a new mainboard for my HEQ5 Pro after it blew. And the board that arrived doesn't look ANYTHING like any other board I've seen for the HEQ5 Pro.

Now the long version. 

In the early part of the week I was running some tests with some new equipment and everything was going great. Right up until the point where I was slewing to M31 and suddenly everything connected to my laptop disconnected for a few moments. My camera came back up, but the mount did not. After some investigation with swapping from my EQDIRECT lead to the handset and back a few times it seemed to be terminal. I disassembled my head and pulled out my mainboard, I then ran through with some advice about changing the two 470uF caps on there which I did and still nothing. So it's proper fried. I discovered the culprit in the end. I had a series of flying leads on the new power supply I bought and it turns out the positive centre of the 12V connectors sit slightly proud so I'm theorising that it touched with the legs of the telescope or with the negative of one of the flying leads and caused a short that blew the board.

So I decided to order a new mainboard:

https://www.microglobe.co.uk/sky-watcher-motherboard-for-heq5-pro-p-15281.html

Whilst that was coming I built myself a little power distrubution box to avoid this happening in future, something would have to go REALLY wrong for something to make a bad connection now.

And so today the board arrived. Except it's not like any other HEQ Pro board I've ever seen. And it's nothing like the picture on their website. I also can't find the board anywhere online.

So here below you can see the old Synscan Rev2 board I blew up and took out, ignore the two poorly soldered Caps in the bottom right.

And here you can see the new board that was shipped to me today.

 

The weird thing is that everything that should be there, is there. They have swapped out the controllers and moved a lot of the components from the back to the front, but there appears to be everything here, plus some extra? They have swapped the PIC micros out for that ARM up at the top, and it's all a little bizare. 

No matter how much I search for this board I can't find any details on it and I'm wondering if it's some kind of knockoff?

Anyway, I don't have much to lose by trying it out. I doubt it could do much damage to my steppers or my hookup board so really it only risks blowing itself. 

So I'll plug it in later and see what I get? 

I'll be sure to make sure that the hand controller portion of it is only putting out 12v and only down the correct pins, but who knows? 

At least the board is more compact.



 

So you know J5 is a fully working USB Port, it just works with ASCOM @115200 baud


i've done it so 100% working

[malc-c]

Yes, Synta are moving away from PIC based boards to ARM based.

If you still have the old board I would be willing to take it off your hands.  I've had some success at repairing blown boards as documented in this thread

Often its a case of replacing the two PICs with new programmed ones which tend to resolve the "no response both axis" issue.

[platesolver_com]

On 29/10/2021 at 13:31, malc-c said:

Sorry, no, the board that came with the mount as I brought it last year, that said I have now seen the pair of PIC's on the other side of the old boards, that said I have Indi inside the HEQ5 now without any external cables other than power just need to get Alpaca working now.

 

[malc-c]

Can you elaborate - you seem to have miss quoted me !!

I was under the impression you replaced a faulty HEQ5 board with one of the new versions.  I don't follow that last sentence regarding INDI

[platesolver_com]

7 hours ago, malc-c said:

Can you elaborate - you seem to have miss quoted me !!

I was under the impression you replaced a faulty HEQ5 board with one of the new versions.  I don't follow that last sentence regarding INDI

not me, the person above who I quoted, all I shared was the USB port on the new boards, then both sides of the old boards, how did I misquote you? im sure if you read again it will become clear

 

[malc-c]

4 minutes ago, platesolver_com said:

not me, the person above who I quoted, all I shared was the USB port on the new boards, then both sides of the old boards, how did I misquote you? im sure if you read again it will become clear

 

 

Looking at this gives the impression I said what's in the quote box !!  " on 29/10/2021 at 13;31. malc-c said"  - ---  AFAIK I never said anything detailed in the quote 😟

 

 

[FabInSpace]

I did myself buy the HEQ5 pro SynScan with the rev C motherboard last year. Some weeks ago the stepper motors suddenly stopped working while communication was still running ok. I am waiting for a guaranty replacement. It’s taken 4 weeks by now. Last weekend I decided to open the mount and take the motherboard out of it for some testing. I did some measurements with a volt-meter and with my digital oscilloscope. I found two problems. It was necessary to replace the n-ch MOSFET 200N06L, and the soldering of the coil on the torus was simply too weak. I did end up adding some glue from a glue gun in the centre of the torus to fix it to the motherboard. The system is running well again.

The weight of the torus with the coil in combination with the weak soldering may very well be a main cause of non running stepper motors in the HEQ5 mount. I think Skywatcher ought to add a gluing between the MB and the torus with the coil (the inductor in the DC - DC converter).

I hope this information may be a help to those of you who experience problems with non running stepper motors in the HEQ5 pro mount.

[malc-c]

Uhmmm so the new revision boards have what may be some flaws.  Thanks for posting your findings and glad you have managed to repair the old board.

[Anthonyexmouth]

On 28/10/2021 at 19:19, platesolver_com said:

So you know J5 is a fully working USB Port, it just works with ASCOM @115200 baud


i've done it so 100% working

So it's possible to mod an heq5 to work with usb instead of eqmod? What would be needed to get this working? 

[malc-c]

Yes as detailed in the post above, the new boards have a USB header on them.  I would suggest dropping a PM to the poster above to see if he can advise further.  You would need to either fit a USB socket to the mount, ideally in the same housing as the rest of the connections and run wires between it and the J5 header, or get a long USB cable, cut one end off and feed it through the housing to the board and terminate that in a plug that fits J5.  It looks like the chip takes USB data +/- and converts it to TTL RS232  serial which gets sent to the controller.  

[wvrfish]

Sorry to resurrect an old thread but it seemed like the best place to post this. My HEQ5 decided to pack in a couple of nights ago (No response/both axes error). I've got a new motherboard on order but decided to dismantle the mount tonight and found what I suspect is the problem.

A component (transistor I presume) seems to have blown in the Q3 position. I seem to have the rev C version. By any chance, is anybody able to identify the part so that I might attempt a repair before doing the full motherboard replacement.

Many thanks

Adam

[wvrfish]

Not to worry, I think I've identified it 🤞

[malc-c]

AO3404 N - Channel MOSFET - You may find it hard to locate one in the UK as they are no longer manufactured but there will still be places like Aliexpress that have stock - but it should be easy enough to find an equivalent 30v 5A part with a 31mOhm  Rds

But I would try and find out what caused it to blow before fitting the replacement board

[wvrfish]

Sorry Malcolm, didn't see your reply - but yes it was indeed a pain to find one, now I know why. 

In the end I got a single part from ebay for £5 + postage. It was supposedly coming from the UK, but took a while to arrive. Once soldered on though, I was very pleased to discover my HEQ5 had come back to life!

No idea of what caused it to blow originally (not very knowledgeable with electronics), possibly the cheap 15V power supply I was using.

[malc-c]

Good to hear that you managed to source a part and you're board is come back form the dead....  Often it's easier diagnosing what's failed than it is to find out why....

At least we now have a reference post to refer to should others with the new revision boards experience the same issue...

[TrevaP]

What is it with Q3 on these boards. The mount (HEQ5 Pro) died in the middle of a meridian flip. I removed the MB and after reading this thread checked out Q3 - sure enough, it was fried.

I'm running this from a LiFePO4 battery at ~13.4V. Never had a problem with this mount or my Az-EQ5. I've been led to believe that this is a safe and even preferable voltage to use. True?

[malc-c]

6 hours ago, TrevaP said:

What is it with Q3 on these boards. The mount (HEQ5 Pro) died in the middle of a meridian flip. I removed the MB and after reading this thread checked out Q3 - sure enough, it was fried.

I'm running this from a LiFePO4 battery at ~13.4V. Never had a problem with this mount or my Az-EQ5. I've been led to believe that this is a safe and even preferable voltage to use. True?

It could be a bad batch of components from the manufacture at the time of production, poor choice of component at the design stage meaning that there is no head room in the event of an over current, or something occurred in the session causing too high a current draw or over voltage to blow the chip.   13.8v was often the preferred voltage to run the older versions of the HEQ5 that used the RevB pic micro based boards.  The MC020 boards seem to use a different power supply configuration, which may be more voltage intolerant and needs 12v +/- 0.5v. 

If your mount is still under warranty then I would contact the retailer from where it was purchased from and send them pictures and a link to this thread to prove that its not an isolated case.  If the board is out of warranty then simply obtain a replacement MOSFET and replaced the damaged one.  It's easy enough to do even with a basic soldering iron and a little bit of care.

[Carbon Brush]

I don't know what Q3 does on the board, but can make a (hopefully) useful comment.

A mosfet like may have a 5A rating, but it can easily get fried.
Can something in normal operation cause a higher current?
It is a characteristic of mosfets that their ON resistance increases with temperature.
Heat them a bit and resistance goes up, causing more heating.......
In other words, they can go into thermal runaway once you start heating.

These tiny surface mount packages have no mass. In other words they heat quickly.
The only way to dissipate the heat is via the copper tracks on the PCB.
You can see the board designer has used thick tracks and vias aruond this part. It is obviously intended for high current.

A quick view at a reputable distributor (Digikey) indicated the device is no longer manufacturerd.
Actually 31m-ohms mentioned earlier by @malc-c for a low voltage mosfet is not something to shout from the rooftops.

If I had one of these boards I would trace out the area associated with Q3 to check what is going on, and fit a different device.
I'm thinking of something with better ON resistance, or something through hole with a heatsink.

HTH, David.
 

[TrevaP]

I bought the mount second hand so warranty isn't an option but I found these which should (?) do the job. (I lashed out and bought 2!) If it blows I'll replace it, think about what may be a more robust replacement and perhaps drop the supply voltage a little.

Edited February 11, 2023 by TrevaP

[malc-c]

Provided the specs match or exceed the original then there is no reason why it shouldn't work, but unless you can find what may of caused the original fault you may find other things blow.  It's like having a faulty appliance that keeps blowing fuses, replacing the fuse with a higher amperage may stop the fuse blowing, but hasn't resolved the cause.

It would be worth keeping us posted on how the repair goes as it also provided future reference.