When reparing wind-up or battery operated toys, you will usually find that over time, the clockwork gets rusty or wires get old and brittle.  Remember that 40 years ago, the materials used in these toys were quite crude.  Even cheap toys made in China today are relatively high quality in terms of materials, although nothing beats the old German and Japanese made vintage toys for their interesting tin and box graphics.  I would love to meet some of the artists that came up with the designs (if they are still with us).

Always check for loose connections, which is usually due to brittle solder and brittle wires.  Always clean gears with a vacuum cleaner (small one made for computers is great) or a compressed air.  Oil up moving parts with machine oil and this will get everything moving again and also clear away rust. 

Be careful not to over-bend metal "nubs" that hold the toy together.  I have done this excessively in the past and they break-off easily sometimes.  Maybe 2-3 tweeks is all they can take.  Once broken-off, they are hard to fix and the integrity of the toy becomes weak.  Resist the desire to flatten them out.  Just bend them enough to get the job done. 

Lastly, check that all is working to your satisfaction before putting the outside cover and clothing back on.  I am often perplexed how it will work fine as a "skeleton" but somehow gets tweeked again with the cover on it.  Sometimes the cover causes parts to bind or bend when putting it back together.  Don't glue anything back together until it has been tested.  Also remember that toys with lights are prone to burn-out.  So keep this in mind that you may have to get back inside to replace a burned-out light.  I recently repaired a mechanical Marx dog with lighting eyes and after I completely sealed it up, a few days later one of the eyes stopped lighting up!!  Burned-out or loose wire?  Not sure.  But pain in the ass to open up again. 

Oh and don't forget.  Sometimes the clockworks are very complicated.  Open it, look at it and you may find that you should just leave it alone.  I have ruined a few pieces in the past thinking I could fix it.  Worst toy to fix.....Puppy with a Brain.  The mechanism is extremely complicated and the springs are hard to keep under control. 

PALSBOSS