Previous 1 15 16 17 18 19 Next 519 Replies Latest reply: Apr 22, 2016 1:03 PM by friguyb Go to original post Branched to a new discussion.
  • ProJay Level 1 Level 1

    If you can reproduce the flicker by running memtest application then you can pinpoint your issue. In my case, I have had no proplem since switched to 16G CL9.

  • OWC Larry Level 1 Level 1

    We've chased on this issue a couple times. Mac mini 2012 flicker/black screen issues have been an issue out of the gate with certain display setups even with stock, factory ram.That said - updates - including a couple earlier this year appeared to eliminate these for pretty much all. Not a cop out, but these systems have not been perfect in terms of video stability for a lot of users right out of the gate.


    The factory design specs for the memory in this model are 1600MHZ DDR3 CL11 1.35V (Low Voltage). 1.35 vs. 1.5V memory uses a little less power and generates a little less heat. Relatively small difference, but it all adds up.


    We have a couple dozen of the Mac mini 2012s in our testing labs and have not had success in replicating the issue. With the information in this thread, going to look at it in a new way + we'll try to get access to a system and accessories that combined create the problem as well.


    Since the current issue is with two displays... and with a report that replacing a mini-Displayport cable was a solution in one of these two display configs - I am having our team look at noise today from the video side. The actual mini-Display port cable we use for the one display witht he Thunderbolt unit being the other display may be related to our non-detection of an issue.


    And... noise would give reason why 1.5V memory (which is what the majority of memory ships operating at vs. the 1.35V low-voltage Apple has moved to), with the higher power draw could potentially reduce that aspect. 1.5V memory does operate just fine in all Apple's systems with the LV spec, just not what was factory intended. 


    CL9 is the CAS latency for 1333MHz. CL11 is the cas latency for 1600MHz. CL9 vs. CL11 I do not believe has anything to do with this. 1.5V vs. 1.35V is what we're going to focus on. Further, as a side note - 1600MHz programmed with CL9 latency is CAS overclocked memory. That would be you don't see a lot of it as there is little to gain with overclocking - unnecessary and tends to increase long term fail probability.


    From testing and a lot of experience, this two display issue is limited to certain Mac minis and potentially further limited depending on what two displays/cables, etc in use in the config. And in this situation - 1.5V may be the solution to overcome it. From the reports here, that appears to be the case and we're going to be on this very quickly.

  • LoriSues Level 1 Level 1

    Any definitve results to share?

  • OWC Larry Level 1 Level 1

    Want to note that this thread has issues being noted with a range of systems beyond just the Apple Mac mini 2012. Issues reported in this thread have included prior Mac mini modesl - factory Ram configs, and including systems (such as Retina MacBook Pro) all memory is factory soldered at that. Issues reported are also not consistent even with the same apparent hardware, OS and EFI(at time of posts) in terms of the extremity of the issue and note too those that have no issues to report at all. Where an issue is present, there is good reason to believe issues being experienced are limited to specific machines and/or the cables and displays in combination use there with. Further - Apple has been well aware of these problems and has been eliminating them over the course with firmware (EFI) and likely within OS level updates as well.



    For the past two weeks we have been doing heavy, ongoing testing with multiple 2012 Mac minis from our 'fleet' of test systems with the 16GB of OWC 1600MHz Low Power (the 1.35V Apple memory spec vs. the 1.5V typical) in working to replicate any issue.


    Testing has been done in compliance with Apple's supported configuration use and with the current Apple OS 10.8.4 and latest EFI updates installed.


    ZERO ISSUES encountered. In terms of load - connected displays tested at max available resolutions. Short/Long sleeps, short/long activity durations between sleeps, same for restarts same for shut downs and cold starts. Heavy video loads on both displays and light loads and in between + real world use by product dev team for daily tasks. hundreds of dispaly sleep/shutdown/restart cycles. And again - ZERO Issues.


    This testing has been using 1 x Apple Thunderbolt Display connected via the Thunderbolt Port


    27" Dell Display connected direct to Mac mini HDMI port,

    24" LG Display connected direct to Mac mini HDMI port,


    same 24" LG Display connected via Apple HDMI to DVI adapter via Mac mini HDMI Port.

    all tests done at max display resolutions.


    We are also flagged to collect any data on a reported issue(none since I replied in this thread) so we can test with exact OS version (although will recommend EFI update if EFI is not to current rev in report), exact displays connected and how connected, etc.


    While we could replicate some video glitches with the 2012 Mac minis with the then at the time current OS and EFI we tested prior a few months ago - with all the latest updates available through today, we had zero thus far in a much heavier, and longer test cycle - longer because nothing could be replicated. Also should note - even the issues we had once seen were not to the severity of some have reported here.


    If an issue is still being encoutered with a 2012 Mac mini that has the current OS and EFI updates installed along with 16GB of our OWC certified and to Apple spec memory, I really want to hear from you. Like to review the exact hardware involved, OS, etc - but ask that you do confirm no outstanding Apple EFI updates.


    Have seen some possibility that in a case using a mini-Display port connected display via the thunderbolt port where a cheap cable can be a core issue. But - this thread isn't about using a mini-Displayport connected display. Also - please note that Apple does not support the use of a mini-dislay port or mini-display port adapted display via a Thunderbolt Display.

    **Apple's anchors aren't working right on this page for me.... it's Q&A #20 in the list though**


    We are happy to do testing with a specific OS version prior to 10.8.4 and see if issue present with such where 10.8.4 operates correct. Also happy to test use of different display and/or a more specific test parameter as well. And... go as far as to take a system in to replicate in our lab and further confirm it's a system isolated issue testing the same hardware on our other Mac minis to confirm issue doesn't occur with that hardware on them.


    If this is like some previous OS/EFI corrected glitches - I'd suspect that with each update to root cause is better and better addressed and issue resolved. Our memory is of the best quality with only top tier, major brand memory devices, and configured to Apple's power and other operating specifications. If anything is 'crutch' that affects this issue in a system that has a glitch still not corrected by Apple's ongoing updates, it is likely the higher power-draw (1.5V vs. the Apple 1.35V) of alternative modules. Until we have a Mac mini in our hands that we can replicate the issue and then test further with, this is speculation, but pretty firm ground on such and it's easier/maginally lower cost for us to build 1.5V - but this doesn't line up with what Apple is using - marginally increases Power use and heat generation - and shouldn't be a necessary bandaid in the first place.


    We're still testing and hope to attain a system with the issue still occurring to really get to the core.


    As an aside - I have been personally using a Retina with 16BB and it was a major PIA before this year's updates. Multiple connecting and reconnecting and restarts to get hot connected displays to come up. At the present - it's now flawless. never an issue anymore. Plug in and go - and I have three different dispaly setups three different locations I use it between. Again, this issue is definitely one Apple has been in general addressing and appears having done so largely with success achieved.

  • JKL037 Level 1 Level 1

    Updated my Mac Mini late 2012, 2,7gig intel core i7, 16 gig OWC ram yesterday. Now running OS 10.8.4. Have the latest EFI updates.

    A few minutes ago my second screen went black again!


    First screen connected via HDMI to DVI, second screen running via thunderbolt to AJA IO XT breakout box, from breakout box thunderbolt to DVI. Plugging cable in/out brings back the screen.

    So the problem still exist.

  • OWC Larry Level 1 Level 1

    This isn't a case with an Apple Thunderbolt display which has been the report in this thread - but none the less want to figure out, etc.


    #1 - What is the display connected via the AJIOXT breakout box


    #2 - Have you tried connecting the display directly to the Mac mini via mini-display port cable to see if the issue occurs?


    #3 Under what circumstances does the screen go black?


    This is a bit of a different setup and scenario to say the least. The breakout box itself is a huge additional wild card in the sequence. That product has multiple Video inputs and display outputs. I am not clear on the exact parameters. you note your screen went black again - when did this start?


    "First screen connected via HDMI to DVI, second screen running via thunderbolt to AJA IO XT breakout box, from breakout box thunderbolt to DVI. Plugging cable in/out brings back the screen."


    Screen #1 connected to Mac mini via built in HDMI port. OK.


    AJA Breakout box first device connected to Mac mini?


    Screen#2 connected via Thunderbolt port on AJA with mini-Displayport connector to DVI display



    Other operations/use, excluding the 2nd display noted, are 100% normal?


    Feel free to contact me as well. Thanks!

  • JKL037 Level 1 Level 1

    Well, I have no Thunderbolt Display.


    #1 I am using a Eizo CG241W as a second display via the Aja io xt breakout box.


    #2 Not lately tested without the breakout box. Before the Aja breakout box I had the noise issues on the second screen, they went away after some software updates.


    #3 The black screen comes so randomly, maybe once a day, or not. I am doing nothing special. I got it one time when editing, when watching a movie on the 1st screen. Maybe watching it full screen. Sometimes it just went black for 1 second. Sometimes it stays black. I can see light or I see that the monitor is having a signal.


    The Aja breakout box have multiple video in- and ouputs, but for my second computer screen, I just use the second thunderbolt connection on the device. It is just a push-through of the thunderbolt signal.


    So indeed, thunderbolt from mac mini to Aja box, from Aja box thunderbolt to DVI adapter, DVI to Eizo display.


    Everything is working fine except for one thing... I don't know if this is related, but I have a sound distortion issue with the Aja io xt box. The box is primary used for putting a video signal from my Avid Media Composer editing software on a external TV via HDMI. The sound from the Aja is send to my active Genelec speakers. When the sound is playing at full scale, it sounds distorted. That's only with the analog audio outputs. Listening to the sound coming from the HDMI signal, it is all oke.

    This problem is being worked on. I have mailed Aja Support about this, and now it is officially a 'case'.

    It is not solved yet, about 3 weeks ago they mailed me that they replicated the problem, and I recieved a case number.


    So there is a change that it is related, and that the Aja box is causing problems, so I guess that I have to test without the box for a while..

  • LoriSues Level 1 Level 1

    Thanks for the tests and the results. Will get some Low Voltage RAM and let you know my results.

  • OWC Larry Level 1 Level 1

    All our 1600MHz DDR3 is low power to the Apple spec. All testing done there with of course.

  • OWC Larry Level 1 Level 1


    The audio distortion at higher volume level percentage could be related to the AJA unit/amplifier in there. That doesn't sound related to the video.


    I think the path with AJA is the best one here. From what you have written, this issue was present prior to and unrelated to the memory upgrade. The AJA box is a big variable - and I'd suspect no issue would occur with it not in the middle... but that's not necessarily meaning it's the absolutely issue.


    other thing - what brand mini-Displayport adatper? We do have confirmed reports where some less than great MDP adapter cables are the culprit and replacing with our NewerTech or Apple's has solved the problem.


    hope this helps and please advise, if you can, what AJA comes back with. Thanks!

  • JKL037 Level 1 Level 1

    The mini-display adapter is from Apple.


    The DVI cable is just some kind of stock brand.

  • OWC Larry Level 1 Level 1

    based there on...


    IMHO -


    The issue is either deeper in the specific Mac mini or within the AJA box. The issue was present with both the stock and the new memory you just upgraded with - so that isn't a responsible factor.


    TB is more sensitive to display signal quality in general, it may be worth trying a different DVi cable - if available, but I honestly see that being the issue as a long shot.


    Looking forward to more from AJA.

  • duncanfromsalisbury Level 1 Level 1

    Can anyone help me?


    I have an early 2011 Macbook Pro and I have just bought a new Thunderbolt 27inch screen. It is fabulous but also flashes black intermittently as has been frequently described. (I also have mountain lion and 8GB ram - the ram was upgraded after the thunderbolt last week and the black outs were happening both before and after the ram change so I don't think is a ram issue).


    There is no pattern to it. A Genius Bar appt suggested it was my macbook pro as the problem didn't seem to happen with a new macbook air in store. Unfortunately we didn't think to test my macbook with another screen. They suggested a new motherboard for the macbook but reading this and other related posts it doesn't look like that fixes it. I have the thunderbolt firmware update.


    It is quite frustrating as reading the posts there doesn't seem to be a solution but people quote varying solutions from ram changes, port cleaning, auto brightness switch off, multiple screen changes. Does this mean the problem seems to sort itself out or is it really a common symptom with multiple causes?


    Any help gratefully received.

  • jfklick Level 1 Level 1

    I just got a brand new MacBook Air and 27" Thunderbolt Display on Monday. They have worked flawlessly until today, so I'm inclined to believe this is fixable somehow. I had fiddled with some power saving configuration yesterday, so I'm going to see if that has anything to do with it. The flickering did not persist through a reboot of my laptop. Additionally, I had my wifi turned off and was working on the ethernet coming from the Thunderbolt connection. When my screen started flickering, my internet connection went to crap too, so it's not just a display problem, it's the Thunderbolt the connection in its entirety.


    Everything has been back to normal for about an hour now (since the reboot), so I'm wondering if this has something to do with maybe the display being told to go to sleep and then not completely waking up (or something).


    I'll continue to observe and report. Both the laptop and monitor are brand new and I had a multi-day baseline of goodness, so I'm hopeful that I can figure out what is different that could cause this.

  • jfklick Level 1 Level 1

    Figured it out! ... at least for me...


    For the first few days, I was running my laptop off of wifi. Then, I needed to do some large, local file transfers, so I decided to plug the ethernet into the back of the Thunderbolt display. *That* is when it starts. After I unplug the ethernet cable from the monitor, the problem persists until I reboot the laptop, at which point it goes away.


    Let me know if this is the same with anyone else.

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