Ok so elsewhere I have covered the other "Syndromes" of the ill-fated Aibo family (well most the ERS-210 up to now) and yet another common problem persists within the Aibo gene pool.
This is the well know (and far reaching) leg and or head tremors. The compact nature of the Aibo family required many many engineering challenges to be overcome without creating a unit that cost $20,000 and just wouldn't sell, so best efforts were used in the name of an affordable product (well sort of)
and a compact unit. One of these best efforts was to use resistive motor location instead of optical location so a small variable resister is used which changes it's output value based upon where the motor (and it's attached limb) is positioned. This was an elegant design and was well used within the radio controlled model servo industry so it was tried and tested. The significant difference between these two methods of use was that in most cases a radio controlled model would be luck to last 20 weeks let alone 20 years and as such inherent wear was bound to come into play. This wear exhibits itself as tremors in the Aibo's limbs and can be quite distressing to watch sometimes and is caused by dirt entering the variable resistor component and altering the accuracy of the output it generates and sometimes it is just worn out. This then leaves Aibos servo motors controlling it's limbs unable to detect their exact position and causes the tremors as the motors continually try to correct their position over and over without success.
The resolution for this is first to determine of it's just dirt ingress or if the part is actually worn out and once this has been determined the corrective method is applied with either the unit being cleaned or replaced.
Most AIbo's exhibiting tremors only do so after many years of use and this syndrome is not normally associated with units that have been shelf queens or are new old stock.
Once repaired the units function normally and as yet none of my own pack that have received this repair have ever re exhibited any tremors (except when faced with my Dalmatian).