HEQ5 pro strip and rebuild

[Leebert]

Lots of showers and not much going on today so I bit the bullet and decided to take the HEQ5 apart and rebuild it. I was spurred on by my last (very poor) attempt at PHD guiding.

I read Astrobaby's web page through 3 or 4 times and went for it.

Well, I was quite nervous about taking it to bits but I needn't have worried. It was surprisingly straightforward.

The end result is very good. It is much smoother. The dec originally felt a bit tight in places. If I tried to move it gently, it would stick and then suddenly move. Now, I can move it gently in any position.

The only tricky bit for me was securing the dovetail mount section back to the main shaft - the three grub screws had to be tightened very carefully in equal amounts or the mount would become slightly tight on one point of its rotation. A bit of time spent here paid dividends and it is lovely and smooth I don't know if this is normal or I am a bit keen tightening things up - I suspect the latter!

Anyone who has a mount which they suspect could be smoother, give this a go. It wasn't as bad as it seemed reading the tutorial. I look forward to clear skies, long subs and round stars

[samtheeagle]

Interesting comment on the dovetail section. I'll give mine a check, as although I've stripped it down and regreased it, I still get a bit of resistance when rotating the dec axis.

[Leebert]

Yes, it had me scratching my head at first. The two sets of three grub screws, if nipped up unequally or too tight, appeared to pull the 'cup' the contains the dec clutch out of round or left it no longer sitting square to the shaft and it dragged at certain points. I probably spent more time getting that right than the rest of the reassembly process.

Just need to wait patiently for the clouds and rain to go away before I can test it...

[badgers]

I did the HEQ5 Pro strip-down and rebuild tonight.

The black gunk isn't there any more, but the white grease that they use seems like awful stuff.

I have to say adjusting the worm gears is much harder than on the EQ3-2, having to unscrew the power module and trying to get an allen key through the gap is nasty.

Anyway, happy to report a lovely smooth HEQ5, and the awful grinding noises seem to be gone now, it runs much smoother.

/salute to astrobaby for another great guide

[Captain Tweaky]

My HEQ5 makes quite a significant 'grinding' noise just as it reaches the 'goto' location. Is this quite normal or can it be reduced by a rebuild?

Yours aye

[badgers]

The 'grinding noise' on mine is much less than it was since the rebuild.

[Etoille]

Sorry to hijack, but seeing this prompted me to think about stripping and servicing our HEQ5Pro. We've had it 4 years now although its seen little use. There's a part of me that wants to stick to the well known adage 'if it aint broke dont fix it' but another part of me reminds me that if I want it to last, it will need to be done sometime and lubricated properly.

Just one question though - does it have to be lithium grease, or can Teflon grease be used instead?

(Dupont Teflon Fluoropolymer Grease to be exact)

PS, ours doesn't seem to grind as some have mentioned here, but I'm fairly sure it is a little more noisy and not as smooth as it used to be.

[badgers]

I think lithium grease is more durable, Teflon is more waterproof and is better on bike chains etc.

Mine was 3 in 1 Lithium grease from Halfords.

[Astro_Baby]

The gears always make a sort of clanking or rattley noise as the mount accelerates or decelerates when doing a GoTo or just slewing at max speed. Its caused most often by a kind of resonance in the gearbox. You can tune it out but its a real pain and not worth the effort really.

To tune it out you need to mess with the motors gears and its incredibly fiddly and an awful lot of messing about. Slightly easier with the 5 and a complete pain with the 6.

As to lube mine were done with a lithium/teflon mix and the lube has stayed fine. Some people have experienced problems with a lithium grease and these days I would reccommend superlube which is a wholly synthetic grease just to be on the safe side.

With that said pure lithium grease, ie made from dinosaur guts is always gping to be a headache but most modern lithium grease types are in part or wholly synthetic. You can see the grease tin in one of the pcs on the rebuild guide and I think it was called TF3. Any decent bike shop should have it.

[Astro_Baby]

Ps congrats on the rebuold by the way. Nice to know all is well and the miunt is better behaved.

[badgers]

Thanks Astro Baby for that Strip-down guide by the way... Between that and your collimation and mirror cleaning guides you must have helped a lot of people out by now.

B

[earth titan]

Thanks Astro Baby for that Strip-down guide by the way... Between that and your collimation and mirror cleaning guides you must have helped a lot of people out by now.

B

Agreed.

[Etoille]

Indeed, I remember this guide being mentioned 4 years ago when we first bought our mount and its still getting favourable mentions today. Of course, it appears to have been revamped/updated and looks even better now!

[Ishan Mair]

Lee, I realize its an old thread. But I've run into a problem after rebuild. So I thought I'd ask. Does RA axis of your mount fall off on east side when telescope is not attached and CW bar is pointing ground (Home position) ?

[kookoo_gr]

Yup, it's because of the weight from the motors that makes the mount east heavy

[Ishan Mair]

Thanks kookoo_gr. Mine falls off real fast. So much that I have attached about 150 grams (0.33 pounds) on the west side of ra axis to counterbalance it. Do you guys have such a weight attached to your  heq5 ? Balance is a real issue for RA axis? Or is mine "defective" in some way? Maybe RA axis is too smooth?

[kookoo_gr]

It doesn't matter if you have a countrweight at the opposite side, i don't have such a counterweight. Once you place the gear at the mount and balance the RA axis this ''issue'' goes away. Your mount is not defective, i have the same ''issue'' it is perfectly natural for the RA to be smooth since you want the axes to move free and smooth without any stiction, what you don't want is play at the RA axis once you move it back and forth by hand if you read astrobab's instructions. The RA axis for astrophotography does need to be a bit east heavy so that the gears are meshed from the gravity

[Ishan Mair]

You cleared it up a lot for me. Thanks. One thing though. I dont quite get what you mean by

Once you place the gear at the mount and balance the RA axis this ''issue'' goes away.

[kookoo_gr]

what i mean is this.

not having any gear on the mount it will flip east side as you described

by mounting the gear and balancing the mount and then you place the mount at the home position you don't have this effect anymore

[Ishan Mair]

Would the east side force of motors is balanced by the gear (telescope, guider etc.)?. If I dont stick those weights on mount,  ra axis goes out of balance as soon as I turn the dec. axis from the home position to point at the east or west horizon. Thats after balancing dec. axis in both horizontal and vertical positions since its a newtonian and then balancing RA with telescope parallel to ground.