Hello Jim: The extender costs are high, and some plugins need several connectors.
I have fixed many TM500 modules by taking a 1-2-3-4 wide mainframe and removing all the covers.
A 1 wide plugin in a single mainframe and 2 wide in a 2 plugin mainframe is ideal, as you have access to every side.
You can still get the PC card edge connectors and DIY.
Kind Regards,
Jon
Jean-Paul