Repair Sony Aibo Head Tilt Joint

This document is intended to help you repair the head tilt joint of a Sony Aibo yourself. The following procedure was first used in summer of 2001 in Gantikow after we (the GermanTeam) had "lost" several of these tilt joints in only a few months (see Headcrash1). A similar description can be found at Aibohack. Because we were not satisfied with these descriptions, this document was written after a big repair session in October 2002. And here it comes:

0. preparations

these were supposed to be the wrong tools

these were supposed to be the right tools

1. remove screws

2. open the case

3.a remove the head to longer the neck (the sophisticated a.k.a. Uwe's method), can be left out if you like it harder


	remove the head cover and screws remove one ear remove the screw that holds head and neck together

3.b may be a little more space by detaching the neck cable holder

4. start to free the tilt joint


before that, you will have to remove the metal part

5. free the tilt joint (without point 3 it's bending the cover, the brutal Aibohack method)

6. unsolder the ribbon cable

7. free the tilt joint

8. prepare opening the gear box



remove white plastic part (you do not have to remember the direction, it's obvious), black protection cap, potentiometer slider and potentiometer

9. open the gear box

10. fix loose parts


Well, now you can see the problem: the metal bar can move inside the metal ring. We have no idea if that happens by purpose (to protect the gear) or not, but after fixing that we can move the head as we would expect it again. Fixing might be done with a couple of nails spreading the hole in the metal bar.

11. check success and improve fixedness with special glue

12. reassemble the head

well, mainly point 9. to 1. should be reversible, a few notes might help you:
(11) you will have to drill a small hole in the glue (after it is dry!), e.g. with a very small screw driver, also remove overhanging glue parts with a knife
(9) reassembling the gear is a twiddle work, check its correctness by impressing a voltage on the motor (3 to 8 volts, so even a mobile phone battery will work fine), the motor should run smooth, the axis should be the rotation center :-)
(8) attach the potentiometer (no glue is needed), attach the potentiometer slider (direction does not matter!, you may have to use a file before because using a heavy hammer might have broaden the metal bar), remember the position of the slider before attaching the black cap, attach the white plastic part so that the central position of the head matches the central position of the slider (only 4 possibilities, shouldn't be too difficult)
connect all cables, don't forget any screw, check the complete head, done.

Appendix A. some words about the costs

if somethings goes wrong, you have more experience and a really damaged head instead of a damaged head
if you are somehow experienced, calculate three man hours per robot
so a good three person team won't need more than 90 minutes per robot (without time for the glue to dry)
3 hours of work instead of 300 Euro for a new head is quite a good deal, isn't it?

Appendix B. some words about repairing the pan joint

the start is pretty much the same
you will have to open the head (point 3)
you will have to loosen some platines in the head as well unconnecting some cables
probably the hardest part is reconnecting the limpid ribbon cable from the mouth
tilt motor and pan motor look the same, we even have exchanged them to make one working head out of two broken ones (one broken pan and one broken tilt) without opening a motor / gear box
there is nothing impossible about repairing the pan joint, but accessing it is definitely harder than accessing the tilt motor