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Skywatcher 250p SynScan GoTo (Help required with SynScan setup)


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Hello dear SGL members, I bought a used skywatcher 250p DOB with SynScan Az GoTo few months ago, but I can't make it work unfortunately. During setup procedure I'm entering correct time format and all the necessary settings and coordinates according to SynScanInit app. But for some reason my scope is not slewing in the right direction. Let's say if I select Mars as a target, scope slewing opposite direction and points down instead of pointing up. :) Also when I use the arrows to move the scope, it looks like that arrow controls are inverted. Left arrow moves the scope to the right and same with up and down. I think I've tried everything and now looking for someone who can help me to solve this problem. :) Many thanks in advance.

Mihail

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Guys,  just to provide some background. The OP purchased this secondhand with a damaged motor board.  I received and repaired the board back in December, and have been in communication with the OP to

I'm stumped.   The  HEX file used was the same as all the previous dobsonian boards I repaired.  Hopefully the previous owner supplied the PC direct cable so that using a suitable USB to serial adapte

???????? I'm totally at a loss.  The cheapest way to identify if its the handset or the motorboard at fault is to get an EQDIRECT cable form FLO  for £33 and then download ASCOM and EQMOD.  If the mou

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Longshot....could there be a separate setting on the controller for use in the Southern Hemisphere? Just a thought..

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20 hours ago, Kinoshnik said:

Hello dear SGL members, I bought a used skywatcher 250p DOB with SynScan Az GoTo few months ago, but I can't make it work unfortunately. During setup procedure I'm entering correct time format and all the necessary settings and coordinates according to SynScanInit app. But for some reason my scope is not slewing in the right direction. Let's say if I select Mars as a target, scope slewing opposite direction and points down instead of pointing up. :) Also when I use the arrows to move the scope, it looks like that arrow controls are inverted. Left arrow moves the scope to the right and same with up and down. I think I've tried everything and now looking for someone who can help me to solve this problem. :) Many thanks in advance.

Mihail

You don't mention which method of star alignment. (Brightest star / 2 star)

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Hello Peter, thank you for your reply. I've tried both, brightest star and 2 stars alignment. Also tried without alignment. Scope flat and pointing North, when I select any target visible in the sky at the moment, lets say Mars, my scope from that starting position, start pointing down to the ground. 

 

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Guys,  just to provide some background. The OP purchased this secondhand with a damaged motor board.  I received and repaired the board back in December, and have been in communication with the OP to try and help him.  The concern was that the repair might be the cause, but I can confirm that would not be the case.  The same firmware is burnt to each of the two PIC micros.  One pin on the pic is taken to 5v via a resistor to identify which axis that PIC needs to respond to.  When I tested the repair I had no way to check the stepper motors, but the handset reported no errors when communicating with the board so it would suggest that it correctly identified both axis.   As far as I was aware it was fine as when it was received back the OP reported the scope moved in all directions when buttons were pressed.  

My thoughts are that the handset has been incorrectly set up so sent messages to the OP on the correct date format and long and lat coordinate entry, especially as there are lots of similar posts which were the result of the mount not pointing at the correct target.   I did however test the motor board through the handset in PC-DIRECT mode to see if the firmware updater application can communicate with the motorboard which it could, so one option the OP has if he has the PC-DIRECT cable or EQDIRECT cable would be to refresh the firmware... but personally I don't feel this would achieve anything as the direction instructions come from the handset.

I'm confident that the firmware update was fine and isn't related to the issue.  IMO, as the scope was secondhand and an attempt to repair it had been made by the previous owner, either some other component on the board is faulty, which as the other chips are just drivers and both motors move would rule that out, or the motors / gear train has somehow been fitted in reverse, again, probably something that is impossible to do.   As its a DOB there are two boards, one the main board, the other a daughter board.  Each axis connects to ist own board, with a flexible cable between the two boards, and the stepper motor connectors are keyed so can't be reversed so that can be ruled out.    One possible area that may causing the mount confusion is if encoders are used.  If these are being misread and sending incorrect data then the handset / mount may think it's reached its target when it hasn't... I've not got a mount with digital encoders to fully understand their function.

I still think the handset has somehow got its  location / date / timezone incorrectly set, OR the handset has been set to EQ mode rather than AZ mode when running through the set up.  Either the OP has done this accidently, or he is putting in the correct information but its not being saved.  I've been searching for info on any way to factory reset the hand controller to no avail, but if it can be reset this may be what's needed to resolve the issue.

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Thank you very much for providing all this information Malcolm, appreciate it very much. :) unfortunately I wasn't able so post so many details as my English and technical knowledge are not very good. I can say that all the coordinates I've entered has been saved in handset and every time I turn the mount on it shows the last coordinates, and all the time, date settings from the previous session. I also performed a factory reset, and it didn't make any difference. Also I've tried to play with W/E N/S coordinates, but no matter what I do scope still pointing down :(

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Just out of curiosity, and not saying it is the case, but are you sure you have the OTA in the mount the correct way round..    Does it look like this?

 10225new.jpg

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I will try to reverse the polarity of the stepper motors tomorrow, maybe it will make any difference, because I've noticed that Dec/alt coordinates on the screen changing opposite telescope movements. 

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So are you saying that the  handset is correctly displaying the right coordinates for the object, but the scope is moving in the opposite direction.  And is that for both axis ?

I don't think you can change the wires - the connector is keyed to prevent it  from being inserted the wrong way round, unless the previous owner trimmed the keyway off and the connector has been inserted the wrong way round.  Bear in mind that the wires are in pairs as you have two sets of coils.  If you connect the wrong wires to the wrong pins you could create a short 

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57 minutes ago, malc-c said:

So are you saying that the  handset is correctly displaying the right coordinates for the object, but the scope is moving in the opposite direction.  And is that for both axis ?

Yes, this is exactly what's happening on both axis. :)

I will try to find a data sheet for those stepper motors or will use a tester to find the loops, thank you for the warning Malcolm. 

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50 minutes ago, Kinoshnik said:

Yes, this is exactly what's happening on both axis. :)

I will try to find a data sheet for those stepper motors or will use a tester to find the loops, thank you for the warning Malcolm. 

Just to rule out simple issues show us a picture of your setup before fiddling with any motor wires, and the details you enter in the handset too.

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I'm stumped.   The  HEX file used was the same as all the previous dobsonian boards I repaired.  Hopefully the previous owner supplied the PC direct cable so that using a suitable USB to serial adapter it would be possible to download the 2.0.9 dob firmware from Skywatcher and try reflashing the motor board, but I can't see how that would make much difference, but its an option.

An alternative, and one that would be a waste of money in reality would be to purchase an EQDIRECT cable, download the ASCOM platform and EQMOD and then use a laptop to test the motor board.  EQMOD would not be useful for controlling the mount as it's designed for use with equatorial mounts, but it would confirm if you pressed the NSEW buttons that the scope moves in the NSEW direction and not SNWE as you currently suggest is the case (and it can be used to update the firmware rather than using the PC-Direct cable).  The problem is that once it proves one way or another that the issue is with the handset, the cable would just lay around gathering dust as there would be no use for it.  You could sell it on the forum, or retain it should you ever get a Skywatcher EQ goto mount and want to use a computer to control it.

Thinking about it, even if the PICs were programmed with the wrong firmware, they would still rotate in the same direction from the home position as an  ALT/AZ mount.  Naturally it wouldn't reach the target as the base isn't tilted.   I can't edit the code, the binary file is simply converted to HEX and then uploaded to the PICs without the protection fuses set.  On the motor board, I believe it's  RB0 (pin 21) is used to identify which PIC is used to control which axis.  The fact the motors move the scope back and forward on both axis would suggest the L239D drivers are working fine.   I know you said you've looked and checked that the ALT motor is connected to the repaired board via the white ALT connector, and the AZ motor is connected to the (possibly unpopulated bare PCB with connectors) AZ daughter board.  If you press the NS buttons on the handset, does the tube move, or does the base rotate ?

I have no idea what the three jumpers do, but you could try removing the jumper altogether and test, then replace it in J2 and J3 positions and see if that has any effect on direction....

Other than that I'm at a loss

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1 hour ago, StevieDvd said:

Just to rule out simple issues show us a picture of your setup before fiddling with any motor wires, and the details you enter in the handset too.

I will post pictures of my setup tomorrow, and will film some video of how the scope behave, but I can say now that all the wires are connected as they should. Here is a screenshot of the app  I'm using to get the coordinates. They are a bit different now, as I'm at work at the moment. But time zone West and North elevation and date I always entering right. :)

Screenshot_20210325-180316.png

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4 minutes ago, malc-c said:

If you press the NS buttons on the handset, does the tube move, or does the base rotate ?

If I press N button (arrow up) scope pointing down, S - up, W - base moving to the right, E - left. Looks like all the controls mirrored

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Ok... lets rule out one thing... instead of using the app and whatever adaptor (bluetooth or wifi) connect the skywatcher handset, enter the date, time and location in the correct format as per the manual and see if the fault still happens.  If the scope works as it should then the problem is with the app you are using 

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Unfortunately previous owner didn't supply PC cable, but I'm thinking of getting one, it's always good to have it. I will try to play with jumper tomorrow and see how the scope behave. Also will post the video of setup process and scope movements.

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2 minutes ago, malc-c said:

Ok... lets rule out one thing... instead of using the app and whatever adaptor (bluetooth or wifi) connect the skywatcher handset, enter the date, time and location in the correct format as per the manual and see if the fault still happens.  If the scope works as it should then the problem is with the app you are using 

I haven't got an WiFi adapter, using app just to get coordinates, before that I was getting coordinates from Internet, based on my location.

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Uhmmmm Time= 18:03:14   ---- 06:03:14 ???  

 

OK just seen your post whilst typing -  you are just using the app to get the GPS location and then you enter that into the handset - 

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1 minute ago, malc-c said:

OK just seen your post whilst typing -  you are just using the app to get the GPS location and then you enter that into the handset

Yep, I just posted the screenshot as example of coordinates I'm entering to the original handset.

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1 hour ago, Kinoshnik said:

Also another weird thing, I can't change slewing speed rate, mater what speed I choose 1-9 scope moves without any difference.

???????? I'm totally at a loss.  The cheapest way to identify if its the handset or the motorboard at fault is to get an EQDIRECT cable form FLO  for £33 and then download ASCOM and EQMOD.  If the mount responds correctly when instructed using the NSEW buttons, and the rates between 1-4 (EQMOD has 4 slew rates) then it would confirm the motor board is fine and the issue is with the firmware on the handset.  If that proves to be the case then purchase the USB - PC-Direct Cable for another £34 and reflash the handset firmware using the PC application and firmware for whatever version the handset is from Skywatcher

You could use the USB-PC-DIRECT cable through the handset with the handset placed in PC-DIRECT mode to talk to the motor board, but since we are trying to find out if the handset is at fault then its best to try the direct method to cut out the handset altogether.

If after this the issue is still present then I really am at a loss and can only think the problem with the fried board and the original botched repair by the previous owner has somehow screwed the board up bigtime.  You could try contacting OVL to see if they can advise, but they are more likely to suggest purchasing a new board / or handset (or both)...

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I just came back home, and first thing I did - removed that jumper from the board, and you know what,  now all the controls are back to normal, they not inverted anymore, I didn`t  try alignment and GoTo yet, but I think we did it this time :) Hopefully it will solve the problem, more than happy! :) 

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