malc-c

It allows the mount to be connected to a computer and controlled via software. It is basically in inbuilt EQDIR cable and uses a prolific 2302 chipset. Connection via usb has been well documented on the forum

Ian, I've just posted a reply on your main thread, but this is excellent news. I really do like to hear that people have fixed a damaged board and managed to get their mounts back up and running for little outlay

Great job Ian, and just goes to show that for a little patience and small outlay you have your mount up and running. Not only saves shelling out £160 or more for a new board when a component costing a few pence was all that was required, it saves items like thins ending up in land fill. Well done... see soldering isn't that difficult

You asked about using a USB cable to connect the handset - what's the wifi got to do with this ??

OK just to clarify this V3/V4 handsets don't have a USB port, they have an RJ11 port. When supplied as part of a goto mount they came with a long grey cable terminated with an RJ11 plug at one end and a DB9 serial plug at the other. If you had an old PC that still had serial ports then you simply connected the cable directly between the handset and the PC. This would allow handset firmware to be updated, or when in PC-DIRECT mode act as a pass through to control the mount via EQMOD or similar. If you had a V3/V4 handset but had a modern computer with out a serial port than a USB to true RS232 adapter would be needed. A driver for the chipset would also need installing on the PC, and this was often supplied with the device. This adapter should never be used to connect the RJ11 directly to the mount's handset socket - it will blow the motor board. The speed of the serial port when used to connect a PC to the handset will be either 9600 or 115200 bits per second. On newer V5 handsets and standard USB A to B cable can be used. From memory it uses a Prolific or CH340 chipset. If its a Prolific 2303 try the attached 64bit driver. The PC should see the handset as just another com port, and as such its worth checking the bits per second rate and try both 9600 and 115200 If you are trying to connect the mount to a PC via the handset, then from my experience the handset needs to be in PC-DIRECT mode to allow pass through of the commands to the mount. If your mount has a USB port then there is no need to use the handset at all. Connect a USB A-B cable between the PC and the mount. Under device manager the PC will see the mount as a new COM port. It will use 115200 bits per second in this arrangement. PL2303_64bit_Installer.zip

Just replied to your PM

Richard, you have basically summed up why this post is now 15 pages long, and why it all started. The OP found out three / four year ago that his motorboard(s) were basically obsolete as Skywatcher had change the design of their goto Dob mount and there was no upgrade path that didn't involve buttering the existing housings, hence the need to try and repair the original boards. This upgrade has continued with other motorboards, migrating away from PIC based processors to STM32 based ARM processors. I have no idea why as there is no real need for more processing power, so can only assume it was down to something else such as product availability, or just a means to make repairing them harder (the reverse engineering of the PIC based EQ6 board was done quite some time back so it's not a new thing). The process of repairing the newer board would be much the same, however soldering the 64pin package is not so easy, and then you have to program the chip via ICSP. I personally haven't seen a new ARM based board in person, so can comment on whether the newer board has more protection against reverse polarity, and shoving 12v up the RX line by using the wrong cable. With regards to the stepper / servo question, the output stages of these boards are basically two H bridges, so could be used to drive either through the PWM (or more correctly PPM). As to the file size, I'm not sure where in the process the file size expands. It may be that the cause is where empty spaces are padded out with zeros, I don't know. If you ignore the warning and proceed the code uploads and verifies OK and doesn't seem to affect the performance or functionality of the mount. For me personally I've looked at what's available to program the newer ARM based boards, but would need to invest in a better solder station and possibly a microscope given how fine the pitch of the pins are. But I'm guessing there are plenty of PIC based boards still in use that will keep me busy...

If its any consolation, I just fixed a SW wifi dongle for a member after the wrong lead was used. The main 3.3v regulator had disintegrated, and he was lucky the motorboard in the mount wasn't fried as well. On the 8 pin RJ45 connector, the two outer wires are supply (pins 7 and 8 are 12v, pins 1 and 4 being GND). Pins 2 and 3 are not used, with pin 5 - TX and pin 6 - RX of the TTL serial connections. If you plug in a 6 way RJ11 which is wired the same way pins 5 and 6 of the RJ11 are +12v, but because it is centred by the clip, pin 5 corresponds with the mounts RX connection, which means you are sending 12v straight into the micro-controllers EUART (TTL serial port), and that means a new board, or (if the board is PIC16F886 based) having the microcontrollers replaced and reprogrammed.

Not that the provenance would be worth much at auction

I'm not a huge Youtube fan as nearly all channels follow the same pattern of using it just to promote their Patron page, social media links and the same unrelated promotors for meal packages. I watched his recent video where a few hundred people paid for him and a couple of mates to have a holiday in the Cannery islands, and whilst he proved a small DIY scope can't compete against a £1m scope (wouldn't take a rocket scientist to work that out) it did provide him with a decent image to flog for £300 to raise more money for a return trip with a bigger telescope...

Glad to hear this thread helped get your Dob back up and running.

On Skywatcher mounts the bar on your mount that the rings are bolted to is replaced by a dovetail which is then mated to a clamp that is cast into the mount. Here's an example of the clamps holding a dovetail You would just need bolt the rings from your mount to the ends of the green dovertail. As mentioned above, if the holes in the rings don't line up with, or are different diameter hole, then modification to the dovertail is required.

You can't be 100% when mixing equipment from more than one manufacture. But chances are your scope might come from the same factory, just under a different brand name. Generally there are two "types" of dovetail bars. Skywatcher uses "Vixen" type, so you would be able to take any optical tube assembly (OTA) that is mounted on this format of dovetail and put it on any Skywatcher, Vixen or any mount that supports this format of bar. Your existing mount doesn't use dovetail bar as a means of attaching the OTA, the tube rings bolt directly to the mount. Now assuming the bolts used are the same size as those that are drilled into the vixen dovetail then it would be a simple case of unbolting the rings on your OTA and then bolting them to the dovetail. If the bolts are smaller or larger than the holes in dovetail then you will need to drill new holes in the dovetail bar so that the rings can be bolted to it. Once you have the Vixen type dovetail (as shown in the links above) you will be able to place it on any of the Skywatcher mounts up to an EQ6. 750 euro should get you a decent EQ5 class of mount. The Skywatcher pro goto EQ5 retails for around eighty euro more, so maybe save a little more before making the upgrade

Venla, looking at the instructions for your telescope it doesn't look as if the upgrade will be a straight forward as you hope. The existing rings bolt onto the fixed bar on the mount rather than using a dovetail. You would need to buy a Vixen dovetail to attach your existing tube rings to so that the OTA can be used on a Skywatcher mount I agree with the poster above, if you can upgrade its worth jumping a step up, but if an HEQ5 is out of your reach then look at getting an EQ5 as a compromise.

I had better reserve one of the refurbished EQ6 boards then, just in case There are guys out there who are far more capable of fixing electronics than I am. Seeing a guy re-ball the main processor on a 4060 GPU graphics card certainly makes my fixies look crude ! - But then the goal is to get these things working again, and if the fix looks a tad Heath Robinson it doesn't matter - no one other than me and the owner will know its there !! Thanks for the praise... I've had a few boards that were not fixable, but it wasn't for the sake of trying...

It's not just mount motor boards that I've been asked to see if can repair. I'm sure the member won't mind me posting this, but somehow his Skywatcher wi-fi dongle produced some of that magic smoke and stopped working. When the hood was popped it was clear that some component had taking a disliking to whatever the user had done. A bit of research and it seems that it is a voltage regulator that takes 12v in from the mount and drops it to 3.3v that the wi-fi chip uses. Anyway, the item was posted to me and I ordered up some 3.3v regulators. Once the board was received I did a quick test to make sure I could find area's on the board that gave access to 12v, 3.3v and ground so I could solder three short wires to. I was in luck and so the 3.3v (1 amp) regulator was CA'd to the board with a small heat sink to the tab To test the board I connected a short length if an old cat5 cable to the dongle, and the once I had identified the 12v, GND, TX and RX lines hooked it up to my breadboard which has a couple of programmed 16F886's on it and powered it on. Phone found the access point and the Synscan app was downloaded to my phone and everything all connected. I was able to run alignment routines etc. the regulator was warm seeing how much voltage it had to deal with, but not excessively, so the case was put back together and a few days later the forum member got their dongle back, which I am told has been working fine ever since Around the same time a new member to the forum contacted me as they had used a cable from Amazon to connect the handset to their fairly new EQ6 that they had purchased second hand and now the mount is dead. Fortunately the handset still worked when he connected it to his EQ5 synsacn unit, but on inspection the EQ6 control board has suffered some damage around the connector for the D9 socket Anyway, with Christmas fast approaching he purchased one of the refurbish boards rather then send his one to me to see if I can repair it, and then send it back if successful. Two days later the replacement was fitted and the member is now back up und running. Once all the festivities are over he will be sending me the damaged board for me to have a look at. If I can't repair it then I have a board that can donate parts if required for future repairs. I asked what cable he got and he forwarded a link to a product on Amazon. It turned out to be a serial to RJ11 cable used to configure router and network switches via their console port. It's a simple enough mistake to make at to the untrained eye it looks like a straight version of the curly handset cable. Either way I told him to bin the cable and provided links to the correct EQDIR cable. So that's another mount that has a new lease of life. It's strange though that the last three repairs have all be EQ6's Anyway, that's two members back up and running.

To be honest a warranty is irrelevant. A lot of retailers seem to think that after whatever warranty period has elapsed any issue that develops is down to the manufacture, or that its "tough luck". This is incorrect. The Consumer Credit act 2015 tumps any warranty. The only issue here with things such as mounts is that just by nature of use there are lots of avenues for the retailer to point the finger at other possible caused and thus wash their hands of any responsibility. There are retailers such as FLO and RVO who try their best to help, but equally there are those that try and wriggle out of it. For example, when you by a £1400 EQ6-R it doesn't come with any "official" power supply. It gives the basic requirements, but within that specification you can get things off e-bay for a couple of quid, to a dedicated regulated PSU costing upwards of £100. - Same with EQDIR cables. Most new mounts come with USB ports, but no USB cable is supplied. So when a board goes pop out of warranty these are things that can be used as a way out of paying up. As you say, often resolving these sort of issues is a lengthy process, and you can end up with a mount that can't be used until its resolved. The risk is then to purchase a replacement part and then try and recover the costs, which as that was never sanctioned by the retailer could still leave you out of pocket.

Your best bet is to contact the importers Optical Vision. Individual parts like that are not listed as spares through a dealer, but I'm sure OVL will be able to advise if they have spares, or could take one off a faulty mount to help you out

Bit of a daft question really... they both achieve the same result, and is only applicable to those with mounts that have the new generation of ARM based motor boards that also have the USB fitted. This basically says it all

Ian, Thanks for the update, and I wish you had pushed for your consumer rights to get a free replacement. Spending around £1400 on a mount you would expect the components to last a reasonable amount of time, especially if it had been used correctly. However, if the board was offered at cost price, then that's better than nothing and a compromise that you were happy with. The availability of the part in the UK doesn't surprise me. I've not looked yet, but I'm betting that a alternative part could be found with specifications similar or very close. It would be interesting to see how you get on with the repair. Please take some pictures as you go and document the process on the "slightly blown motor board" thread here (with cross ref to this original thread). That will help anyone else who might have the same issues.

A mount with a USB port has both options as mentioned. Use a USB A-B cable and the built in 232 TTL serial to USB chipset, which as mentioned is predominantly made by Prolific which needs a dedicated driver under windows. Or purchase an FTDI based EQDIR cable to replace the handset. The speed difference of 9600 compared to 115200 baud is not really anything to be concerned over as there is very little two way traffic. There is a risk that the movement of the mount could mean the USB cable gets disconnected, especially if the rig is set up and broken down each session as the socket would ware over time. Regardless of connection, the mount is seen as a virtual com port under windows. FTDI drivers are built in to windows so installation of an EQDIR cable is straight forward plug and play. The USB requires a 3rd party driver to be installed, but again, nothing complicated. Under windows control can be via EQMOD or Green Swamp Server (GSS).

Thanks for going to all that trouble to ID the Q3 component. I'll check for component availability (or similar) later when I have a little more time, and drop Ian a PM with a view to attempting a repair

Regretfully there are no official schematics for any of the Synta Synscan controller boards. Some like the MC004 found in Dobs have been reversed engineered by some cleaver folk, but the schematics are not guaranteed to be 100% correct . That board you have looks to be an old revision as the microcontroller of choice prior to the migration to ARM based processors was the 16F886's. No expert in electronic design, but I do know that from repairing dozens of control boards there is very little protection (if any) built into the boards. A simple arrangement of a couple of diodes would protect against reverse polarity, so why this wasn't part of the design I never know.

There is no difference. If you have a mount with a USB -B port then it saves the expense of using an EQDIR cable as its not needed. The TTL 232 serial to USB conversion chip that you find in an EQDIR cable is already mounted on the mounts main board and connected to the USB port.

Grab yourself a beer or coffee and spend an evening reading through all the similar posts like yours where people want a scope on a limited budget. You'll soon see that it's not a cheap hobby due to the initial outlay costs, and if you want something that will give the results you are expecting then budgets need to be increased. In your case forget a telescope and invest in a decent set of binoculars. A decent brand of 8 x 40 or 10 x 50 binoculars will give you nice views and still have change in your pocket. If you are insistent on an EQ refactor then expect to double, possibly treble your budget in order to get something of any practical use that is sturdy and have some level of precision.