The NT7B75GD, NT7B75GE and first version NT7B75GF are known to have issues but not all of them....for me directly is was NT7B75GE that caused the CICS to reboot every so often.

If it fixes it you could put the old card in the other slot for safe keeping if needed in an emergency and or if it has non restricted software then they can add more lines.
Pry out the tabs a little with a small driver then pull them out further with your fingers and slide it out evenly.

Funny thing today....as for the cover I curse it now, today I did a site survey for relocate and last tenant left a CICS and Callpilot, all I had were my keys and could not get the bloody cover off for nothing to see the software version so it will have to wait when I relocate and have tools.

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www.curlycord.com
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Toronto, Canada