Modern oil derrick not pumping

Yes. The newer one with the circuit board failed on me too. I sold mine for half of what I paid. Plus the tube kept cracking. The fluid would spill all over the layout. What a mess.

Apparently it's a reminder for you to not buy the "crap".  You may be better off going to get Postwar beat up units with the bi-metallic strip.

On a more constructive possible solution: I had one once where the 555 timer chip IC was the culprit.  I replaced the 555 timer chip and it then worked.  You need to be OK with de-soldering (using a small iron, no 100 watt guns here please ) to do this since it's 8 pins soldered to the board.  I don't recall it humming when it didn't move, but it's been a long time since I dealt with this issue.

How "modern" is your unit?  20 years old?  MPC from early 80's ?(I don't have one that vintage, so I don't recall if they used strips or electronics) Most recent one they made?  (I don't know if more recent ones still have a discrete 8 pin 555 timer chip that is replaceable).  The one I did that for was the 12902 Marathon version.

-Dave

I can do basic soldering, but nothing too small or critical. I've got a herd of them so I'll just swap it out for now. I have some good old postwar ones too. But they're off in deep storage. I'll try newer derrick #2 today and report back on it's functioning.

Thanks

It's a small chip (a google search or Wikipedia have pics) that would probably just about fit on your thumbnail.  If you can desolder all 8 pins, (need to use braid, solder sucker, etc) that's the hardest part.  It's much easier to solder in the new one.  Also need to not apply too much heat to hurt the traces on the board itself, but that shouldn't be too much of an issue if you use a low wattage iron.

-Dave