In article . com,
says...
I'm not sure if this is the correct place to ask this question, so if
I'm too far off topic, please let me know where I should post.
I have a GE microwave, model number JVM1870BF07, which I am trying to
convert to recirculation mode for the vent fan.


GE's web site has installation instructions.

http://products.geappliances.com/Pro...nt/Dispatcher?
REQUEST=SKUOBJECTS&DOCUMENT=Installation%20Instruc tions&SKU=JVM1870BF

The filter goes behind the grill that over the oven's door. A #1 or #2
Phillips screw driver is need to install it.