Can't leave my EQ3-2 DEC motor drive alone...

[JamesF]

Having spent a fair while trying to improve the DEC motor drive backlash on my EQ3-2, I attached a pointer to the gearbox output shaft and noticed that it skipped every so often. I took this as a bad sign and beating the moths from my wallet sought out the cash to buy a replacement motor set.

I've promised the old RA motor and gearbox to two other SGL members who wanted them as soon as I've got the new drives set up and confirmed they work (was hoping to do that this evening, but despite the forecast of clear sky I can't even see the moon for cloud at the moment , but I wasn't happy with the idea of offering the DEC unit to anyone. In the spirit of experimentation I therefore decided to really go to town taking the gearbox apart.

I split the motor and gearbox (again and then using two pairs of pliers levering against each other where the gearbox sideplates are joined by brass pillars, gently eased them apart. They split fairly easily, giving me full access to all the gears in their gloopy greasy glory. Out came the isopropanol and all the parts spent twenty four hours soaking and were then scrubbed with a small brush to get them clean.

I'd taken photos, but it was actually relatively straightforward to work out how to reassemble the gears in the correct order and orientation, lubricating them lightly as they went in. Offering up the two sideplates again, I was able to just snap them back together in my fingers and the gearbox holds together perfectly.

I'd expected some improvement as a result of this work, but was very surprised to find that whereas it was almost impossible to turn the gears by hand using the output shaft before I started, they now spin very easily.

For comparison, I split the new DEC drive too. There's no sign of the dreaded black grease in that one and it has less backlash so I think I'll leave it in place. It's tempting to give the new one a try though...

James