Machine has issues, so pulled the micro-sd card - cannot be read on windows machine, so try to put it back - has fallen into the bottom of the machine.
Is there some trick to installing the new one that doesn’t require disassembling the machine?
Langmuir - this is bad design - things like that should be easily accessible - likewise for things like backup batteries.
I used an air nozzle and a mechanics pickup claw.
You know the thing that you squeeze the end, and 3 little claws come out of the end of the thing?
Gently blow some air around until you can see it. Some guys use a stick with blue tape on the end. Good luck.
Blue tape on claw is the way to go. Being the Linux guy, I’ve built some mad skills retrieving that dropped card. Got pretty good on the fifth retrieval.
unless you have one that leaks then the tape is a flop!!! 
I have only lost it once during the 20 times I have removed it twenty times. I had a hell of a time getting the new etch to work, but I finally got it to work. The air pressure in the cabinet that @holla2040 told me about worked the first time. The fact that my machine has no leaks at this point is a plus. I placed a rag inside under the Orange PI first.
Good to hear, I resorted to the same. I have giant hands and couldn’t get them both in there at the same time. Hence honed my ability to retrieve a dropped card.
I see they make a SD card extenders
Wonder if that would work
Work great, use them in many of my consoles.
Hopefully, you won’t have to touch it again. I have looked at the through-panel type and kept it on the front of the machine. It comes with an 18-inch lead and a dummy SD card to plug into the PI.
Had a hellavuh time getting a dropped SD card out. It was gone. Blasting air in there for over an hour. Used a camera to look around. Nothing. Resorted to drilling holes into the back of the machine where I thought it was. Located it far left corner pinched under a cable by the oil tank. Was able to fish it out.
Got the new SD card with the proper software on it. Looks like I broke the SD card slot trying to get it in. :-/
I used this contraption and drilled a hole in the side. You can plug the card in from the outside. Amazon.com
It have to go out the side. The ribbon cable is only 12”.
Ah yeah I’m using an extension but it’s a tail inside the machine. Nice find on that one.
Its waterproof as well.
No doubt, it is a bad location. I changed mine out from the front of the machine. First, by placing a towel under the slot to catch the chip when it gets dropped so that it cannot fall into the bowels of the machine, then by using a mirror behind the slot so I can see what is happening from the front. A small ladder is needed. My new chip from Sam did not click when installed, but it did fix the slow startup and back gauge problems. Thanks Sam. Now if they would only come out with a revised chip to fix the shut down problem when limits are reached. Obviously, the chip should be on a extension. If I had to replace the chip often, I would use a 2 inch hole saw and cut an access in the box directly behind the chip.
