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Cloudy nights make for DIY projects - EQ6 Polarscope Dimmer


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Hi all,

Hopefully this will be useful to a lot who find themselves in my position.

I arrived at Kielder fully prepared (or so I thought) and never even considered the polarscope LED dimming as the last time I used it I was using the handset. The V3 handset has a function deep in it's bowels that allows you to dim the polarscope.

But, of course, EQMOD doesn't and I was left with the LED at its brightest, which makes seeing through it impossible.

I was talking to Richard who said the handset doesn't have the function but I was sure it did. I didn't argue as he's the experienced one and I'm the newbie. But on returning home I found I remembered correctly. Doubt is a dangerous thing! lol

But he suggested a great temp solution which saved my evening. :( But shining a torch down the polarscope, with the mount switched off, was never going to be a long term solution.

I considered a resistor inline with the LED but quickly discounted it as I wanted control and not just one guess at the correct dimming.

So I decided I'd fit a potentiometer. This would allow me to dim from near-off right up to full-on. Perfect for different conditions.

After checking around I found very few people with solid info so I decided to go for one from RS. I picked a 470k one as it seemed close enough to what a few sites had mentioned and would give me a nice variation.

Funnily enough, when I received it I did a little further looking around and found our very own Astro Baby had used this exact potentiometer on her EQ5! What's good enough for Mel is good enough for me ;)

Fitting this was super easy. Couldn't have been easier, to be fair.

1: Simply drill a 10mm hole (I chose the area in the image because it was the least disruptive). Remember to remove the circuit board from the panel first ;)

2: Solder two wires to the potentiometer's terminals - one to the wiper (long one) which goes to the LED and one to any of the other two. Insert in hole.

3: Snip the live wire (Red) coming from the board to the LED so you have enough to connect both wires from the potentiometer. The wire from the wiper terminal goes to the LED and the other goes to the wire coming out of the original socket.

4: Solder these and heat shrink them. I used Black simply because I ran out of small Red :p

5: Reassemble and enjoy the fact you now have fully controllable polarscope illumination :D

I hope this is usefully to some of you who don't have the latest V3 handsets or don't use the handset at all.

Images below are just so you can see the clearance inside the circuit board, the wires coming out, and the final look. I think it looks like it was always meant to be. The ON OFF is obviously regarding the power ;)

Also, while you're there, checkout the terrible build quality of the HitecAstro EQDir box. I had to replace the socket and wire but the box looks like it's just chopped with a knife or something :) Works though, suppose. :)

Thanks for looking :)





Edited by astroimpulse
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Still not had a chance to test this in the real world. It's going to work perfectly but jeez...this weather is a joke.

If there was anything to ruin my enthusiasm for this past-time...the past 6 months of weather would be it :o

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Thanks for sharing this great mod Sy. I was at Kielder too and tried shining a red torch at an angle down the polarscope - also after getting this advice from Richard! It got me by, but it was a bit of a pain so I'd like to do this tweak to my EQ6.

Although I've got a soldering iron & I'm confident to drill & solder, this is new territory for me.

What gague of wire should I buy and how do you heat shrink the sleeves? Is there a cheap gadget to do this or an alternative way of insulating the joint.



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Seems like Richard saved a lot of us that weekend :( Salute to Richard :o

As for the gauge of wire...I'm not sure :D It's very very thin but still thicker than the original wire. I just used some I had lying around from an old servo switch. The 14 AWG I had to specially buy for my power station is far thicker (I had to get the right one for the job on that). Maybe it's around 20 to 22 AWG (I didn't bother to measure it).

Have a look inside and then see what you have lying around that is similar. It's safe as the amps running through to the LED will be negligible (20ma or so).

As for the heat shrink...I have a gas soldering iron (heaven sent) and it has a hot air blower attachment. But you can use a lighter and waft it over until it shrinks. I often do for quick heat shrinking. Easy part really. Just remember to slide the HS over the wires before soldering :D

The result is a fantastic solution and a surprise it's not stock. But I guess they (Synta) expect people to use the handset. Which is fair enough.

You will know the clumsiness of the torch shining and this has solved the issue. It dims to near off so you have a plethora of brightness levels to choose from :)

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d'oh for some reason I had my handset with me at Kielder....and mine does change the brightness....I'm sure it's part of the handset flash upgrade.

Anyway, maybe we could ask Chris if he can add this to EQMOD....if it's on the chip they must be able to do it.

Nice tidy job though.

Let's hope the clouds clear before you build a world conquering robot army! :o

Nice one.

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:o Robot army sounds good :( If only I had the skills :)

Anyway, maybe we could ask Chris if he can add this to EQMOD....if it's on the chip they must be able to do it.

Yeh, was thinking this too. Seems it's only recent V3 handsets. Wonder if there was any hardware changes?

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Cheers for that :o

Makes sense as I've read some V3 owners don't have the option.

Don't know what the thinking was behind the super bright LED. Even an Kielder there was no way of see a star though it on full.

Anyone can do this mod (any version mount) so hopefully it's useful to somebody else :(

Edited by astroimpulse
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  • 5 weeks later...

I had the afternoon spare so I thought I would give this nice little mod a try.

Completed in around half an hour and works perfect. No more powering down the mount and shining a red torch down the hole to check polar alignment mid session.

Thank you Sy. :)

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Apparently It depends on the Motor Controller Hardware revision as well... so need

Yes it does...but once dimmed it stays dimmed, I have a new NEQ6- pier mounted and had to use the handset to dim the LED but once done it stays set.

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I had to opt for the mod as my mount has the v2 handset so no option to dim the LED. I was holding out for the EQMOD team to add this function as a software solution if possible but as it was simple hardware mod I thought why not.


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  • 5 months later...

Anyone had this little "issue" when carrying out this mod? One of the hex-head screws has sheared inside the RS232 head, leaving me a pain-in-the-rear job of getting it out. Caused, it would seem, by Synta's wonderful idea of sealing them in with super-glue. The metal in these screws is typically rubbish without the added stress of rotation against the wishes of the glue. Thanks guys. :rolleyes:

Still, I'm sure the end-result will be worth it. ;)

Thanks for the tips Sy.



Edited by Takahashi
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  • 2 months later...
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