malc-c

I think that there would be little chance the main board has the same fault as mine as the mount is fully functional when used with the handset. I personally prefer a direct cable connection. Bluetooth has always seem flakey in my experience

Wow, that's a strange one. The fact the mount works fine with the handset would suggest the main board is fine, and its an issue with the EQDIR / BT adaptor. But you say that they both work with a second mount ?? - very confusing. Do you have an other PC that hasn't been used with the adaptors and try and install EQMOD and Ascom on that, then connect up the EQDIR cable and see if it communicates with the mount. If it does then the issue is with the original installation on the main PC. This may be port handling within Windows, or simply a corrupt driver that needs re-installing.

I just received an e-mail from OVL, they contacted a "skywatcher engineer" who gave the following response

Geoff, thanks for the explanation. I was guessing it was more PSU related as the charge pump caps would seem to be the four smaller caps near the PWM driver chips

Hi, No problem. It was the two 470uf 25v caps (top right of your picture). There was nothing physically obvious with them (no bulging or leaking) - I have no idea what part they play in the circuit, but swapping them out resolved the issue for me. Good luck

Well, thanks to a recommendation from a fellow SGL forum member, I contacted a guy on the East Midlands Stargazers forum. It was suggested that I replace two capacitors on the board as these seem to be very sensitive to voltage drops / spikes and fail. I didn't have the right can size as the ones I had in my electronics box were 35v rated rather than the 25v rated fitted by synta, but they were persuaded to fit, and as it isn't as if anyone is going to see it ! Well I'm pleased to say the mount is now fully operational

Does anyone know what the part number of the four 24 pin driver chips are on the mainboard are

Thanks Chris for the confirmation that I'm on the right lines... so what do you think cold be the issue, or how to go about diagnosing the main board

Thanks for the comments. Regretfully as the mount is permanently set up in an observatory I no longer have the handset, so have no other means of testing. As the mount requires an external USB to serial adaptor, this does indeed suggest that the communications is handled by the PIC micro, which would in turn suggest that the issue is driver chip related rather than processor. But the fact that 90% of the board is surfaced mount components diagnosing what needs to be replaced will be hard. It really peeves me that there is no easily replaced protection components on these boards, and power spikes, glitches etc can cause such a main component to fail - and at £100 a pop (no punn intended )

Due to an accident last summer I've not used the telescope in the observatory over the winter period. A few weeks back I gave the observatory a spring clean, and checked the scope was still operational by driving it through RA and DEC using EQMOD on the PC, it was fine so parked the scope and that was that. Today I thought I would see how the sun looks, so powered up the mount from the Fusion 13.8v bench PSU, booted the PC, placed the solar filter on the scope and slewed to the sun. I needed to do a small adjustment using the gampad and that's when I first noticed something nor quite right, the mount began to track at the adjustment speed on the same axis, so I re-targeted in DCD and it locked on. A few moments later I could smell electrical burning coming from the area of the PC / PSU - I bent down to check the PC and as I did glanced at the PSU to see that it was still showed nothing untoward such as a massive current draw, which it wasn't, showing little over an amp being drawn. However the PSU then went POP and the display went out. I disconnected the wires to the mount and removed the unit. Opening it up the smell of cooked electronics was striking - but there was no sign of anything obvious, no smoke, no scorched components or anything burst open. The only thing I could find was a wet patch on the board which looked like it had sweated or a viscous fluid had leaked - but none of the capacitors had vented, unless it was from underneath. OK so I need a new PSU. But I need to power up the mount and park it so I don't loose all the sync points in EQMOD. I got a 12v -2amp wall block PSU from an old network switch and connected that to the mount. Where EQMOD was upset and displayed Time Out Comms issue, it now displayed Long / Lat/ RA / DEC info etc, so the mount was communicating with the PC, but I couldn't hear that audible high pitch whine from the mount, and using the gampad or PC the mount fails to move. I do however hear that initial clunk you get when you first power on the mount, so power is getting to something, although manually turning the motors there is no difference in resistance when power is turned on or off. I've tested with a DVM and I'm getting 5v (or close enough) on the main board connectors at various pins. So I'm at a turning point. Do I shell out the £100+ for a new main board, plus another £30 for PSU, or is there a possible simple fix. I've been involved in electronics for over 30 years and you would seldom find that a complete board has failed, and that it's often a small descrete component that has failed (diodes, or regulator) - seldom a PIC or driver chip. The thing is I'm not sure if the communications come from the main board which would suggest the PIC micro is running, or if it comes from the power board where the handset and power connectors are. Any suggestions ? Malcolm

I must admit the felt I've used has held up, just my ignorance in thinking the way I folded and overlapped the felt at the edge of the boards would be enough. If I had used this flashing material with a belt and braces approach then the OSB may have been fine. If I ever need to re-felt the roof again, I may look at using the MDPM rubber. Maybe for those who are at the design stage should take on board the true amount of pitch required to ensure proper water run off. The fall on my roof was at the calculated minimum, but having it dropped by 2" wouldn't have caused me much of a problem in reality as I'm not a tall person.

We'll almost 7 years since starting the build I've had to undertake my first repair to the warm room roof. The other week whilst getting something from the observatory I noticed that the inside rear corner wall had water marks running down it, and the internal plywood at the edge where it joined the wall was darkening and wet. I got the steps out and went up onto the roof to find standing water in a small shallow in that area. I couldn't do anything about it then given the snow and rain that we were having. Today the weather was decent enough to lift the felt and have a look at where the leak was coming from. I was shocked to see that the OSB under the felt was wet and falling apart. The area was about 8" wide by 18" long from the rear edge. The wood wasn't rotten or black, but you could break it easily with your hands. Considering the roof was fine (I stand on it whilst cutting a hedge) last Autumn, the damage occurred rapidly over the winter. It seems the water had got in between the folds in the felt at the end of the side panel, and then as the wetness was drawn up by the wood, it sagged causing the water to remain rather than run off (one of the pitfalls of having a shallow pitch). Having removed all the old damp wood I cut a strip of timber from an old draw front I had laying around and made it fit the hole as tightly as I could. This was then screwed into the frame and then covered with 150mm wide self adhesive flashing obtained from B&Q. This was quite pliable and could be moulded around the side panel and under the tracks for the roll off roof. I used several strips to cover the area and make a good seal. The felt was then re-laid and the track refitted. For good measure a further strip of the flashing material was applied over the fold of the felt to ensure no water could seep back up. It probably hasn't cured the standing water issue, but at least the water can't now (hopefully) get back in. So word of warning to anyone who is planning or constructing their own observatory. In hindsight I wished I had used 18mm exterior grade marine ply for the roof as it would have stood up to the water a lot better than the OSB and would have made the repair a lot easier. But then given this is the only issue I've had with the observatory in seven years I guess it's testimony to the construction methods used and I shouldn't complain. Some commercial sheds don't last this long

I started this post five years ago (almost to the day) and pleased to say that my annual maintenance this year, like the last, consisted of a coat of preserve and the addition of a couple of galvanised nails to provide a better attachment of one small section of shiplap on the roof where the constant movement over the years and the expansion / contraction due to heat and cold had made a small gap between it and the frame. That was it for another year ! It's pleasing to find that something I've built has withstood temperatures from -12c to 35c (in the shade), 18" of snow, gallons of rain and hail the size of baked beans, and winds up to 62mph yet still looks as good as the day it was completed

Martin, thanks for the comments. Looking forward to seeing your build.

Fantastic construction... really solid. Keep the updates coming...

These days with cat6 cabling it's less of a problem.

Well the FTDI 232r -5v cable supplied to a UK address is the same price as a Hi-tec Astro cable from Rothervalley Optics. When these first came out they were upwards of £50 so it was worth making your own, but now there's hardly much point in a DIY option if obtaining the genuine FTDI cable.

There is also a large blob of solder on the pins of the chip itself, which looks like it's shorting a couple of pins, so you may of been stuffed before you even unpacked the thing from the jiffy bag !

The PL2303HX chipset has 3.3v TTL level I/O, not 5v. Some pins are pulled high to the 5v USB lines via internal pull-ups, which might explain why you are getting different voltage levels on different pins, although if it is connecte dto the mount, you will get nearly 5v on RX line as the mount will be sending TTL signals at 5v levels. The EQMOD site recommends using FTDI chipset at 5v TTL levels, and whilst these may well be 10x the price of the e-bay listing direct from FTDI, they work well and are well supported by FTDI if you ever experience an issue. Spending £15 on a decent cable is nothing when you have a mount costing £700 or more, and I personally wouldn't risk damage to the motor board by using something from HK at less than a quid.

Can't agree more !! WOW... makes a change to see the traditional cubic meter foundation above ground than below !! One thing for sure, that mount ain't gonna have any stability issues !

Nice find.. I personally prefer not to rely on a mechanical connection, but for those who want a quick way of making an EQDirect cable, that's a great suggestion

Yes the EQDirect cable that suits the HEQ5 will work with the EQ5

I think it's in relation to what that part is. Buying a cheap eyepiece will still give you a view of a target same as an expensive one. OK the expensive one will give you a better view, but neither will pose the risk of damage to the scope. However the price difference has a factor into what item you get. A genuine FTDI cable can be had for £10, whilst the cheap far eastern cloans are just a few quid. For the sake of the few quid difference it's well worth getting a geniune part. It's nice to see that HitecAstro have reduced their prices on such cables. They used to be £40 - £60, now they are a more realistic £28, but then again they use the prolific chip and not an FTDI, which has been know in the past to have issues with driver compatibility. Astronomiser uses FTDI, and have products competivley priced http://www.astronomiser.co.uk/eqdir.htm and state If you really want to save money, but use a genine part that you know won't brick the mount - yes, using cheap cloans can result in the product it is used with becoming a non functional door stop ! - then purchase a cable direct from FTDI for £16 and an RJ45 plug (or network cable) and you'll have an EQDirect cable for less than £20.

Seriously, these mounts are upwards of £700, the EQ8 being a few grand. Purchese a genuine FTDI cable from the manufactures. I wouldn't (didn't) risk using what can only be cloan chips costing a couple of quid off e-bay. Drivers up to windows 10 are available http://www.ftdichip.com/FTDrivers.htm Alternatively, if in doubt, spend £40 - £60 and purchase one of the commercially made EQDirect cables that will have a warranty, and if things go pearshapped you can have some course of redress. It depends on your confidence. Personally using genuine FTDI chips I have no worries with the DIY cable I made and use with my HEQ5, which has been fine for the passed three years

Thanks for the reply. Having the scope permenatly mounted in the observatory makes it a tad awkward to het visual on land based targets, but I'll try it out once I've resolved the issue I'm getting with Python, but that will be after I fix the observatory PC which crashed on me this afternoon !