Cheap learning opportunity?

[DrEntropy]

...or succumbing to GAS?
Found a 24~120mm 3.5~5.6G Nikkor "kit" lens yesterday, cheap 'cause the AF is INOP. All else is quite good. Got the service manual downloaded, had time to do a partial "exploratory" in the evening. Had some interesting half-results from just cleaning contacts on the main PCB. Sometimes the AF will now work after turning the manual focus ring to shortest distance. Intermittent AF? So now a more thorough tear-down and diagnosis. Meanwhile, this AM, a bit of play with it:



Some "barreling" evident at 24mm:

 

[Basil]

Was this a local purchase or mail order?

 

[DrEntropy]

On line from a seller I have a history with. They wanted rid of it rather than pay to have it repaired. The commercial repair would exceed the value of the optic for them. If I need to replace the motor, it still makes it a good deal (no counting my 'labor' as it's a classroom of sorts for me).

 

[equiprx]

So now a more thorough tear-down and diagnosis.

Since I was a kid back in the 1950s I had to take things apart to see how they worked.
The table in my bedroom was always piled high with 'projects'.
Even today, my shop is cluttered with machines that were junked.
Sometimes I actually refurbish the things.
Not so much lately, since it's hard to stand over a shop bench for long.