Refurbishment of a SkyWatcher Startravel 150/750 Refractor

[savcom]

I've recently acquired a 'pre-owned' Skywatcher Startravel 150/750 refractor on an EQ5 mount upgraded with Synscan.  I hope to document my refurbishment of this scope one step at a time as a record of what I have done - and, hopefully, provide you with a) amusement and b) a guide if you should wish to do the same.

First steps were to put it all together and see if it works:

 

[savcom]

After proving it all worked, and noting the condition of the optical train, I've gone ahead and built a lead to connect the handset to my computer, then used this to upgrade the handset to the latest version of firmware:

Cable first:

I ordered a 1m RJ12 '6P6C' cable from Amazon.  This allows me to make two cables.

The 'correct' colour coding for an RJ12 6P6C cable is as follows:

For the Synscan RS232 cable you need to wire three cores to a DB9 female.  These cores are:

RJ12 Pin 2 to DB9F Pin 2

RJ12 Pin 3 to DB9F Pin 5

RJ12 Pin 5 to DB9F Pin 3

If the colours in your RJ12 cable are correct, then this woud be:

Black to DB9F Pin 2, Red to DB9F Pin 5, Yellow to DB9 Pin 3. 

But you shouldn't rely on the colours being correct, so, Step 1 is to note the colours in the cable you have and see which pin they go to.  Mine was wired the wrong way round to the standard as you can see below.

So I need to connect:

Yellow (Pin2) to DB9F pin 2

Green (Pin3) to DB9F pin 5

Black (Pin 5) to DB9F pin 3

Step 2 - take the insulation off the cut end of the cable

Step 3 - Set the DB9F up for soldering (see the DB9F pins are numbered)

Step 6 shows the DB9F with the three cables soldered

You can cut off the three unused colours (Red, Blue and White)

And finally here is the finished cable ready for testing.

Edited January 16, 2021 by savcom

[DaveL59]

As a word of caution, you might want to check others opinion here as updating the firmware may not be that beneficial and can be a road to bigger problems. @malc-c and others here will know more than I on this. I've never upgraded mine as it works just fine.

[savcom]

10 minutes ago, DaveL59 said:

As a word of caution, you might want to check others opinion here as updating the firmware may not be that beneficial and can be a road to bigger problems. @malc-c and others here will know more than I on this. I've never upgraded mine as it works just fine.

Thank you @DaveL59.  It's true that there are arguments for and against upgrading firmware in devices that are working, but looking at the Skywatcher site I see that my old version of firmware (3.27) may have issues with the GPS module, so updating to the latest version (3.39.15 at the time of writing) corrects this and ensures other fixes are included.  Providing the sequence described in the Skywatcher notes are adhered to, there are no difficulties in updating the firmware. 

If anyone has experienced issues with newer releases of firmware, I would be happy to hear them.

[savcom]

I went ahead and updated the firmware using the procedure outlined in the Skywatcher documentation (making sure, as I had a V3 handset, that I downloaded the correct software for both my PC and the handset.  The software page for the V3 handset is

http://www.skywatcher.com/download/software/synscan-v3-hand-controller-firmware/

Powering on my handset with the original firmware showed this screen:

I then connected the handset to my computer using the lead I made above:

and powered the handset on with keys 8 and 0 pressed to put it into 'Update Mode' as you can see on the display.  Skywatcher refer to this as the bootloader, if you're looking on their site. V1.7 is the latest at the time of writing.

I then went through the steps outlined in the update notes and the new firmware is now installed:

I've connected this back to the mount and the setup I had originally stored (lang/lat and height) was still present.  The mount controls worked as expected.

 

 

Edited January 17, 2021 by savcom

[mikeDnight]

I love these scopes! They make great comet seekers, and show some of the best views of open star clusters and nebulae. If it were mine I'd give it a respray and mount it on a sturdy Altazimuth so I could glide aimlessly through the constellations, soaking up the glorious diamond dust vistas. The finest view of the double cluster in Perseus I've ever had was through a Helios 6" F5. Something I'll never forget!

Edited January 16, 2021 by mikeDnight

[savcom]

I had noticed that some of the buttons on the handset were not making contact without a firm press, so I opted to carry out a basic service of the internals of the handset.

Turning the handset over shows four screws in the base:

Once these are released the cover can be removed - but a word or caution.  While the main PCB remains attached to the base due to age, the LCD display is screwed to the top, so, if you are not careful splitting the base from the top you will put strain on the LCD cable and risk damaging it.

When opening the unit therefore you should carefully ensure that the main PCB comes up with the top of the handset and stays with the display.

Once fully separate you can gently fold the main PCB back over the display so that it is ready for a clean

You can see that the switches are the black contacts in the silicone rubber membrane that make contact when pressed, to the gold contacts on the main PCB.

I then gently cleaned each of the PCB switch contacts with a fibreglass pencil to wipe away any tarnish or deposits and then wiped every contact with a cotton bud soaked on electrical contact cleaner.

and as you can see, there was a fair amount of crud picked up on the bud.

I did the same to the keyboard membrane:

The final stage was to reassemble the handset taking care to reseat the membrane properly and fold back the main PCB.  I made sure the LCD flexible cable was properly seated in the connector on the main PCB

After re-assembling the case I then took another bud and cleaned the contacts on both the RJ12 and RH45 sockets.  If you do this, make sure you only slide up and down the connector fingers.  Don't go from side to sdide or you risk damaging the socket and possibly the handset.

So that's the handset done now and ready for service.  In testing the handset does seem to respond more readily to key pushes, so this looks to have been successful.

 

 

 

Edited February 9, 2021 by savcom
Caught a spelling mistake

[savcom]

26 minutes ago, mikeDnight said:

I love these scopes! They make great comet seekers, and show some of the best views of open star clusters and nebulae. If it were mine I'd give it a respray and mount it on a sturdy Altazimuth so I could glide aimlessly through the constellations, soaking up the glorious diamond dust vistas. The finest view of the double cluster in Perseus I've ever had was through a Helios 6" F5. Something I'll never forget!

Thanks for this - I couldn't find many favourable comments about the scope when I was researching it.  Everyone says it was too fast, so would have chronic CA, but for me, who is also interested in DSOs, a scope capable of decent wide-field views is just what I want.  I know I can't expect great results if I image, but I have just bought a 72mm ED refractior which will do that, so I can shoot through one scope and observe through this one.

I fully intend a respray in time togetrher with a refurb of the mechanical parts of the scope.  Optical steps first though, as you will see.

For now, that's as far as I want to go with the mount. I do want to service it, but I hope the service will form additional posts in this thread at a later date.  For now, I want to start some of the initial refurbishment of the scope optics, beginning with the diagonal.

Edited January 16, 2021 by savcom

[cloudsweeper]

@savcom - I've had similar problems (handset button failure), so might try this.  I've also updated the firmware (Celestron) - far from an easy procedure, and it didn't seem to make any difference anyway!

Doug.

Edited January 16, 2021 by cloudsweeper

[savcom]

I then started on the optical parts of the scope.  These steps are basic housekeeping that should have been done by the previous owner, Anyways - on with the refurb, starting with the diagonal:

Here is a view into the diagonal.  I've tried to focus on the surface of the mirror to show you wnat the state of the optics were.  Pretty dreadful.

The diagonal is held together by four bolts on the base. 

Undoing these and gently separating the base shows the mirror is on top of a thick piece of glass supported by two softer pieces, one to provide blackness and one to support the mirror in the diagonal

Here is a picture of the mirror...

First stage was to blow as much of the crud away as possible before any cleaning could be done

That made a large difference, but it was only after cotton buds and lens cleaning liquid was used that any real improvement was made

The result - much better.  And before you say the surface is still dirty, I was using a piece of foam above the mirror to force the camera to focus on the mirror surface.  Now, the surface is so clean, you are seeing the surface of the foam in the picture.

After blasting any dirt out of the diagonal housing, I carefully re-assembled the diagonal and repeated the first view showing a much better mirror surface.

Next step: Finder scope.

Edited January 16, 2021 by savcom
spelling

[mikeDnight]

1 hour ago, savcom said:

Thanks for this - I couldn't find many favourable comments about the scope when I was researching it.  Everyone says it was too fast, so would have chronic CA, but for me, who is also interested in DSOs, a scope capable of decent wide-field views is just what I want.  I know I can't expect great results if I image, but I have just bought a 72mm ED refractior which will do that, so I can shoot through one scope and observe through this one.

I fully intend a respray in time togetrher with a refurb of the mechanical parts of the scope.  Optical steps first though, as you will see.

For now, that's as far as I want to go with the mount. I do want to service it, but I hope the service will form additional posts in this thread at a later date.  For now, I want to start some of the initial refurbishment of the scope optics, beginning with the diagonal.

I think its a shame when people choose to view certain scopes in a negative light. I think of the 150mm F5 achromat as a specialist instrument. It's speciality of course being rich star fields, comets and brighter deep sky objects. It would make a great variable star scope too. And even with its chromatic abberation, it will show those piercingly sharp, diamond dust star fields better than any reflector ever could. I bought the 150mm F8 version in 1999, while three of my friends bought the 150mm F5. The F5 never failed to impress me as a deep sky scope, but surprisingly, it could still give pleasing views of the Moon and planets upto 200X. It had CA, but that's just the nature of the beast. It's not actually a fault!  Just enjoy it for what it is and not for what it isn't. I'm sure it will make you very happy! 😊

[savcom]

The next step in this refurbishment was to inspect and clean the finderscope.  On the 150/750 the finderscope is a 9x50 unit with a cross-hair reticule supported in the standard Skywatcher finderscope mount.  

As with the diagonal this hasn't been protected much against the elements and both objective and eyepiece lenses were quite grubby.  I will need to source new covers for this scope, so if anyone knows the diameters of the covers or the Skywatcher part numbers, please let me know. Thanks.

Looking at the objective you can see that it is pretty grubby again:

It's harder to see, but the eyepiece is just as grubby

I checked the internal surface of the objective and found it was clear (and so it should be - it's not exposed to the elements) but I did notice the non-reflective coating of the finderscope will need to be re-done when I repaint the scope.

After blowing the dust off the objective, I then cleaned with lens cleaning fluid and cotton buds.  Pretty dirty again as you can see.

Here's the eyepiece after cleaning

And finally the objective after cleaning

 

[savcom]

Last post this evening - the two eyepieces are also cleaned.

The scope came with 10mm and 25mm Plossls which are adequate to start with.  New eyepieces are on order but not delivered yet ...

Without their covers on the eyepieces again need a clean, so using the blower I removed the dust and then, with lens cleaner and cotton buds I got rid of much of the grease and dirt.

This looks a little smeary so I will see in the morning to see if this can be improved.

 

[jock1958]

10 hours ago, savcom said:

As with the diagonal this hasn't been protected much against the elements and both objective and eyepiece lenses were quite grubby.  I will need to source new covers for this scope, so if anyone knows the diameters of the covers or the Skywatcher part numbers, please let me know. Thanks.

Great thread this and thanks for the tips especially cleaning the electrical contacts which I hadn't thought of in relation to a non astro problem I have with my dodgy central heating timer .

As far as lens covers go you can be as creative as you like, I use a variety of protectors ie:  plastic bottle tops, electrical blanking caps and rubber caps off eBay, basically anything you can think of that keeps your lenses clear of dust. Couple of pics below, the black soft rubber caps I bought off eBay & yellow plastic cap from my spares box which I've seen in electrical suppliers & eBay.

 

 

Edited January 17, 2021 by jock1958