Fixing a Tak CAA

[LewisM]

I grabbed the 2.7" Takahashi CAA (Camera Angle Adjuster) off the trader the other day for a really good price. When it arrived today, the first thing I noticed was it was rotationally stiff - too stiff to be used in fact (with the clamping nut loosened of course). Having disassembled a couple CAA's before for the same reason - and the reason is always grease that has solidifed to glue (considering this CAA is over 20 years old, it was not a surprise), I got into this one. The tolerances between the moving parts is so close that even slightly hardened/dried grease will gum it up (has to be so tight to stop any flex in the unit).

Step one is to remove (or loosen completely) the small grub screw - and I mean SMALL - that locks the silver ring. Old ones have a slot, newer ones have cap screws (tiny little boogers!). Thankfully, mine was a slot head, so out came the trusty jeweller's screw driver.

Next is to unscrew the silver ring. I tried using rubber boa (rubber strap wrench), but no go - kept slipping. So, I grabbed some aluminium bar stock, measured and drilled holes for M3 screws. I threaded the holes as well as using nuts. The bolt head fit the ring dimples perfectly (maybe could round it a little to stop any possibility of scratching if it slips, but that didn't happen anyway). Ring came off easily.

Now the inner rotating black section was glued solid, so a few deft blows with a delrin mallet, and the ring came out easily. I then cleaned the solidifed grease out of the ring and cast body, regreased with INOX electronics grease, reassembled and tried it.

SMOOTH AS (as the kiwi's would say).

Simple. So long as you are even slightly adept with using tools (and making one) and slightly mechanically minded, this is such an incredibly simple and quick fix. Takahashi's are NOT scary - just have a go! Expensive to replace if you booger it though

Photos:
1. Silver ring showing the dimples for removal of the ring
2. Silver ring small grub screw that must be removed PRIOR to removing silver ring
3. Inner rotating section
4. All the bits
5. Inner surface of CAA body
6. Custom made tool

[Kunama]

Well done there Lewis!

[LewisM]

Ta.

One thing I never understood was when a visual astronomer gets a Tak with a CAA, the first thing many do is sell the CAA.... I find the CAA INVALUABLE for visual, as you can move the visual back to any angle you need and NOT have to loosen the EP clamp, or worse, the diagonal holding screws.

Yeah, CAA means Camera Angle Adjuster, but it serves BEAUTIFULLY as an EPAA

[issdaol (Phil)]

Nice :-) Agree on the use of the CAA makes it a lot easier visually :-)

[casstony]

Thanks for the demo Lewis - I regreased a CAA today with Superlube synthetic grease and it now works nicely. This CAA is only 3 years old but it wouldn't turn at all.

I used Superlube as I just happened to have it in the shed having previously used it to fix a seized mount. I used two 2" nails through a piece of wood to get the silver ring off.