Why is hdmi so unreliable?

srichards

srichards

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I've got a mac mini-dvi to hdmi adaptor to try and run the laptop on the projector. It hardly ever works and it seems for no reason at all that it stops! I plugged it in just now and the mac switched to a new resolution and it actually worked! I changed it over to pal and it was still fine. Then I accidentally clicked the 'detect displays' button and the stupid thing doesn't work and won't display anything other than a blank screen. I've tried unplugging and replugging the mac end, the switch box end shutting the mac and re-opening the lid. It's not the hdmi switch end that's the issue. That clicks over to the correct input but the mac isn't outputting anything other than a blank screen. It's so frustrating as to why it works once then won't work a second time.

Anyone else know any tricks for 2008 macbooks and how to make them work with hdmi consistently? If I unplug the mac then the switchbox goes back to the pvr as it should.
 
Sounds like your adapter is being funky then. If your sure its not your HDMI switch or Cable, it the adapter.

I've got an Adapter and never had one issue with it, and used it on several macs...
 
It's not the switch. That switches over to other inputs ok and displays them ok. It displayed the mac one for the few minutes it was working. It's definitely the mac end that is the issue somehow I think.

It was only a cheap lead. Apple don't do them any more as it is the old mini dvi standard not the new mini display port standard. There are a few people that have had problems with hdmi and macs.

I'll have to try cancom and see if they have any.

I'm wondering if it's made some kind of configuration file that I could delete and make it redo it again?
 
srichards said:
It's not the switch. That switches over to other inputs ok and displays them ok. It displayed the mac one for the few minutes it was working. It's definitely the mac end that is the issue somehow I think.
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Not necessarily. The HDMI spec has a hot plug detect which can potentially be mangled by the switch. I'd do as Neil suggests - start off with the iMac connected direct to the projector and see if the behaviour is consistent. 2008 was just when HDMI was taking off, so it is possible some quirk is stopping it work properly...
 
Ugh. Quirks I do not need!

I shall be annoyed if it is the switch. It's not that old. It's a neet one.
 
If I plug the cable into the mac and the projector isn't on already then the mac screen switches automatically to a lower resolution and then it works ok. This is with the switch in place. I don't understand why the projector being on would mean the same sequence wouldn't work! Certainly not going to press the detect display button again :)

I'll try it without the switch box and see if it is any better. Projector is 2006/2007 so very early in the hdmi scheme of things.
 
srichards said:
If I plug the cable into the mac and the projector isn't on already then the mac screen switches automatically to a lower resolution and then it works ok. This is with the switch in place. I don't understand why the projector being on would mean the same sequence wouldn't work!
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Because the hot-plug detect isn't working properly. There is a lot going on to get HDMI working there.
 
Ah. Will reset the SMC on the mac again at some point and see if that helps. The projector model is appearing in the display settings so I think it has more of a handle on it this time.
 
Those adaptor cables do fail. I've just replaced a mini-displayport/hdmi cable only last week.

I think I've still got the older version - mini-DVI/HDMI. I'll check in the morn.
 
Cable should be ok as it is a few months old and yesterday was only the second time it's been plugged in!

It's behaved ok this evening. I just have to remember to plug it in before turning on the projector then not mess with it in any way at all.
 
Looks like it could be. Projector is quite old too so it may not deal with later devices so well. But it's always ok with the pvr. That's ok whichever order it's turned on. It's definitely the mac that is the most awkward with the whole thing.
 
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