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I have a mid-2007 iMac (EMC 2133, 20"). I upgraded the CPU and WiFi card in order to run Collin Mistr's High Sierra Patcher tool. That worked fine.

Now I need to connect a second display. I hooked one up via a mini DVI to HDMI adapter, and it gets recognized in system preferences, but the display says no signal. I have tried on multiple monitors, reseated the cables, reset the SMC, rebooted both the computer and the monitor multiple times, yet still nothing.

I'm starting to wonder if it has anything to do with the hardware/software upgrades.

Does anyone know how I might make this work?

This has been said to be a possible duplicate of HDMI to DisplayPort Not Working. However, it's a different problem. I have tested that this works on a different Mac (going from mini DVI to HDMI monitor). There seems to be no problem going from mini DVI to HDMI.

Basically, here's where it's at:

The setup:

Mac -> mini DVI to HDMI adapter -> HDMI cable -> External display

The external display definitely works. The HDMI cable definitely works. The mini DVI to HDMI definitely works. The Mac seems to be the problem.

marked as duplicate by Allan, IconDaemon, fsb, dwightk, Glorfindel Feb 27 at 7:29

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