ben_mtl

I meant my two Az boards. For Alt I only have the replacement board but for Az I have both the original and the replacement one ,which are identical and make the Az motor rotate in opposite directions. Would that mean that at some point there was a modification in the firmware that changed the direction of rotation ? That would be strange... I don't know how old is my telescope. When I ask the hand controller what is the firmware version, I guess it gives me the version of the Atl (master) board, so I cannot know what's the version of my original Az board

Wow that was a quick reply, thanks ! Yes I'm aware that reversing the polarity of the motor is risky, first I'll wait and see if Dobson owners can confirm what is the expected sense of rotation. How would you explain the fact that I have two Az board supposedly identical (MC004 Rev F) that move the motor in opposite direction ? I thought about a different firmware version but not sure that would make any sense...

Hello everyone ! Firstly, I went through this entire thread and I must say it was a pleasure to read you guys helping each other out with so much dedication and determination 🙏 I bought a second hand Dobson Flextube 300P about 3 months ago and I'm having a very strange issue with this famous MC004 board. I know that the previous owner had to replace the hand controller and the Alt motor board but I have no information about what happened exactly. The motors seem to work fine with the leatest firmware and there is absolutely no connection issue with the hand controller but I've never been able to perform a star alignment. After several experiments my conclusion was that the Alt motor was rotating in the wrong direction, and I was comforted in this conclusion when I saw a review video on youtube showing the rotation of the OTA. Indeed, my tube goes up when I press the down arrow of the controller, which is different from this video. The Az motor was ok though (going left when I press the left arrow). Now comes the interesting part : actually the previous owner got a replacement board for both Atl and Az so, out of curiosity, I replaced the Az board and now the Az motor is rotating in the opposite direction ! (going left when I press right). So I was convinced that there was a problem with these replacement boards and I was starting to think about switching the two black and red wires that go to the Alt motor, but then I saw this video posted by pablocarlac at page 10 of this thread, which matches my current situation. I just try to perform a 2-star alignment, chose Deneb as the first star (pointed at manually) then selected Altair as the second star, and the tube went in the wrong direction in both Atl and Az, so I'm pretty confused now... I would have three questions : 1) I would be very pleased if Dobson owners here could share which way their tube is moving with relation to the arrows on the controller. 2) Is there a setting I'm missing, which could correct the sense of rotation of the motors ? I found nothing in the hand controller manual. 3) Let's say I put the original Az board back, how stupid is my idea to switch the 2 wires that go to the Alt motor ? (see picture below) Some additional precisions : - My long/lat coordinates are set up correctly. I also have the wi-fi adapter so I can use the SynSan app instead of the hand controller, and it behaves the same way. - I contacted the SkyWatcher support and their only solution is to buy a new base at 900 $US +tx +shipping... Thank you very much in advance.