acrylic cinema hd display keeps turning off

Discussion in 'PowerPC Macs' started by gargantu, May 2, 2016.

  1. gargantu, May 2, 2016
    Last edited: May 19, 2016

    gargantu macrumors newbie

    May 2, 2016

    The problem I posted about below seems to have developed into the Mac simply refusing to turn on if the monitor is plugged in now. If I unplug the monitor, then plug it back in the Mac turns on, emits a loud long beep, during which the power light rapidly flashes. The big fan inside then goes into overdrive for a few seconds before calming down and then the Mac boots into Open Firmware. I can then type mac-boot and the Mac boots into OS X and has no further issues provided I don't shut it down. I can put it to sleep and wake it from sleep but if I shut it down, it won't turn back on again unless either I unplug the monitor and press the power button, or I plug the monitor back in.

    I've tested the PSU and it seems OK but I've not completely ruled it out. I've also used a completely different (but identical) acrylic 23" Cinema HD display, and also swapped the graphics card for a different working one (a Geforce Ti as opposed the 9000 Pro that was in it originally) and neither has fixed the issue. I've reset the PMU several times as well, and tested the backup battery (it shows 3.7v so might be OK), all to no avail.

    **original post below**

    Hi, anyone can help? I have an old acrylic cinema hd display, 23" (M8536). I use it with a june 2003 mirror drive door powermac g4.

    It seems to have developed an annoying habit of turning itself off randomly. Though I don't know if it's the monitor that's the problem or the mac (I can't test it on another mac to find out). When it first did it, it just went off and the power light on it started to flash, so I unplugged it and plugged it back in a few times then after that managed to restart the mac a few times too and it seemed to work fine again for several days of use. Then today it's done it again, worked for all of 30 seconds after turning the mac on and then just went off only this time th epower light didn't flash, monitor seemed completely dead and couldn't get anything out of it.

    Again, unplugged it and plugged it back in, power light came on, then went off again, screen still stayed black. So, I pulled the power on the mac and I've left it now. I haven't tried it since but I figured I'd ask if anyone's got any ideas on this. Googling seems to bring up a lot of similar problems but they all seem to be about more modern versions of the monitor rather than these old acrylic ones.
  2. eyoungren macrumors Core


    Aug 31, 2011
    ten-zero-eleven-zero-zero by zero-two
    Could be your Energy Settings putting the display to sleep?

    First thing I'd check.

    However, here's something for you. I suffer something akin to your problem periodically with a 20" ACD. I will wake my Mac and the screen is dim because of the bottom backlight not shining as strong as it should. The power light starts to flash at that point.

    I have found that the colder the room is the more likely I am to have this happen to me. If I keep the display lit for some time I can usually disconnect the display while the Mac is on and reconnect it. Sometimes it only takes once, sometimes a couple of times and in rare instances I've had to do it several times.

    I have noticed however that my best luck in this is once my ADC/DVI converter box gets nice and warm.

    Is the room you keep your Mac in generally cold? See what happens if you let the display get nice and warm.
  3. Hrududu macrumors 68020


    Jul 25, 2008
    Central US
    With just about any other Mac I'd say it's almost for sure the inverter, but the MDDs and their terrible PSU could just as well be the issue here if the monitor isn't getting the correct power from the Mac. Any other computers you can attach it to? Either way, I hope you can get it going again
  4. eyoungren macrumors Core


    Aug 31, 2011
    ten-zero-eleven-zero-zero by zero-two
    That's a good point about the PSU on the MDDs. I had not considered that.
  5. gargantu thread starter macrumors newbie

    May 2, 2016
    If it's the psu, I'm assuming probing the power out pins on the adc port on the graphics card with my multimetre tool would help show that? It's the only way I can think of testing for a power issue, since as I say I have no other way of testing the monitor (this is the only mac I have with a adc port).

    I'm not sure about the psu. Must admit the way it's been acting certainly comes across as if it's got a power issue there somewhere. The mdd has an actel psu in it, not sure what wattage it is though. Got a feeling it's the lower wattage version that they used instead of the "400w wind tunnel" originally but, I might be wrong, I'll have to go look at some point.

    As for other suggestions, pretty sure it's not room temperature or the energy saving system. That room is always warm, and the energy saving is set to turn the monitor off after an hour of inactivity.

    Could the monitor cable be a culprit? The cable on mine is OK but the connector sure isn't - it's seen better days. Mostly just the plastic is a bit broken around the edges etc. Also two of the pins on the connector look like they stick out more than the others though, not sure if that is normal.
  6. havokalien macrumors 6502a


    Apr 27, 2006
    Kelso, Wa
    best fix is get the adc to dvi converter box and use that as the power supply. ADC to DVI or VGA to DVI converters to that and the load will be taken off the mdd altogether. The power switch and sleep should work just fine even with all that as i use it that way on mine. I am alway scared the PSU in my cubes are gonna get weak so i use either VGA or converters to not tax the power supply.
  7. gargantu thread starter macrumors newbie

    May 2, 2016
    Those things are a bit too expensive, they seem to go for more than what I originally paid for the monitor. If it is the psu which I need to test really, I think I'd be better off just replacing the psu since currently it doesn't really drive much so if it can't handle the monitor intermittently it's probably on the way out anyway.
  8. MagicBoy macrumors 68040


    May 28, 2006
    Manchester, UK
    Flashing power light indicates it's likely backlight or inverter related.

    The top backlight started only working intermittently on my 20" Acrylic. So it's gone to be recycled, and the useful parts passed on to @LightBulbFun ...
  9. gargantu thread starter macrumors newbie

    May 2, 2016
    OK here's some new info, so perhaps someone could chime in if they recognise any symptoms. Sorry but this will be a bit long winded as I explain exactly what happened so bear with me.

    I bought a new monitor. Well, not new obviously but new for me - it was very cheap, boxed in excellent condition and with original software cd and manuals so already three up on my old monitor so I took a gamble. Wasn't expecting everything to work right off the bat, and it didn't.

    lSo here's the weird thing. I plugged this "new" monitor into my Mac and I got nothing from the Mac this time. I press the power button and the Mac wouldn't turn on. I unpluged the new monitor, the Mac switches on as normal. I plug the new monitor back in after I've turned it on the fans slow down a bit then the Mac shut off within a few seconds. "Oh dear" I thought.

    I tried pulling the power cord out and plugging that back in a few times, still got nothing. So I unplugged the monitor and the power cord again. Sat there for a few about ten minutes pondering on what to do next. So, I unplug keyboard and mouse because the cable was kind of getting in the way as I was moving the Mac around. I plug the power cord back in. Then plug the new Monitor back in (keyboard still unplugged, mouse is connected to keyboard incidentally).

    As soon as I plug the monitor in the Mac turned itself on which was kind of surprising. Nothing happens for a few seconds then the Mac emits a loud long beep that lasts for about two or three seconds. While it's doing this, the monitors power light is rapidly flashing, almost like it went into disco mode. The beep stops, the flashing light on the monitor stops and goes solid, and then the fans in the Mac go on FULL BLAST. Not even joking.

    Now I've had this Mac running hot in it's past and I've had the fans blowing quite loudly but I've never heard them blowing like that before. It sounded like it was about to take off! This lasted for a few seconds before it quietened down to normal. The monitor came to life and showed my the mac rom boot screen thing, didn't have any errors apparently, just said to type mac-boot to to boot the OS or mac-shutdown (or something like that) to shut down the Mac.

    Of course, keyboard was still unplugged so I plugged it back in to try and boot to OS and, the damn thing wouldn't work. Tried plugging it into the two different usb ports on the back (think it only has two built in) and it I got nothing from either the keyboard or the mouse (not that I was trying the mouse, that was still plugged into the keyboard ports).

    Also by this point the Mac's power button seemed to have zero affect to me pressing it or holding it so I just pulled the power cord out again since it seemed like the only way I was going to turn the Mac off (it was only after this I remembered the monitor has usb ports on i somewhere too, I think, I haven't looked but it was too late by that point even if it did).

    So, guys, what do you make of that? Still PSU? Or... maybe the NVRAM got corrupt or something? I think the battery in this thing is buggered. When I was fiddling around with before all these problems transpired I had to reset the nvram using the keyboard key press pattern because it randomly decided it couldn't detect my wireless pci card anymore and I think I have lost the date and time at one point completely randomly too (but it didn't do it again because I left the mac switched on at the wall).
  10. MacCubed macrumors 68000


    Apr 26, 2014
    Considering the fact that it is a G4 MDD, I bet on it being the PSU. They are prone to failing, and as this happens with two displays, and the Mac even refuses to turn on correctly, makes me believe that its the PSU. If you have a multimeter, you can test the PSU.

    It also could be the graphics card, as the display uses ADC. The best way to test this is by ordering a cheap Mac ATI Rage 128, and testing the ADC port. Do this before replacing the PSU, as this could be the issue.
  11. gargantu thread starter macrumors newbie

    May 2, 2016
    I will test the psu as and when, and also the graphics card. But I think though given the annoyance of obtaining the parts and potential cost involved with the psu I'll leave it to last though and explore other potential avenues that may be causing the issue first. The fact it booted into open firmware by itself and appeared to be working sans keyboard and mouse has got me thinking about something a bit closer to the logicboard being the problem.

    Oh wonders will never cease. if I didn't need this mac for OS 9 I'd have thrown the ****er in a dumpster by now.
  12. d-oost macrumors 6502a

    Jan 10, 2016
    Sounds like a bad PSU to me, too. I was going to suggest converting an ATX PSU for your MDD, but I then realized normal ATX supplies won't supply the 25V required for the ADC displays, so that'd be useless in this case.
  13. gargantu thread starter macrumors newbie

    May 2, 2016
    Well, if it was the PSu and I did an ATX conversion I'd aim to modify the new supply and add in the ADC voltages. I doubt it'd be impossible (difficult maybe, depending on the supply used I suppose). However that would be if it was the supply.

    But it doesn't appear to be. I did all my "simplest solution" tests yesterday and then moved onto the PSU and tested it as best I could with whatever specs I could pull of the net and it appears to be functioning well.

    This leaves me with either the graphics card, the logic board or a related hardware component tucked away somewhere.

    Again, after I'd done all this I put it all back together, tried turning it on and got nothing. Unplugged the monitor (this is still the "new" one I obtained a few days ago). Plugged the monitor back in and once again, it fired up on it's own, power light flashed rapidly, long tone beep then the fans went on full blast, calmed down after a few seconds and then it booted into open firmware.

    Only this time i hadn't unplugged the keyboard/mouse so I was able to type mac-boot and get it to boot OS X 10.5.8, which it did. And I've had it running ever since (currently about two hours) with not even a hint of an issue.

    Any ideas?
  14. LightBulbFun macrumors 68020


    Nov 17, 2013
    London UK
    the Power Light flashing rapidly then a long beep would happen if someone held down the Power Button down long to start a firmware update... now I am not sure if you can hold down the power button on a ADC cinema display and start a firmware update but I would make sure the button is not stuck on or something (same for the main power button on the MDD). also when you say the MDDs fans slowed down then it turned off when you plugged in the ACD sounds almost like theres an electrical short somewhere and the MDDs PSU is tripping out id check cables etc make sure none are damaged
  15. gargantu thread starter macrumors newbie

    May 2, 2016
    Perhaps I just won't turn it off anymore. Sweep the problem under the rug, so to speak. It goes to sleep OK and wakes up for instance so if I just leave it asleep rather than turning off so I won't ever have to turn it on and suffer with the issue... assuming the old original issue doesn't come back the monitor randomly turns itself off after a period...
  16. gargantu thread starter macrumors newbie

    May 2, 2016
    Only me again. Tried a different graphics card (GeForce Titanium) and that didn't fix the issue. So I've tested the PSU again. Last time I used some info I found on other threads around the net of people saying how to test the PSU but this time I found the service source manual for this Mac and it has a testing procedure in it. DC voltage test, stick the black probe in pin 12 and follow the guide;

    Turn on the power supply but don't turn on the computer.
    Red probe on pin 14 shows +25v. Passed.
    Red probe on pin 1 shows +5v trickle . Passed.
    Try and start computer. Doesn't start.
    Check to see if power fan is spinning. It isn't (no ****).
    If fans aren't spinning... Replace power supply (say whaat?)
    So, I unplug monitor and plug it back in to get the Mac to turn itself on and with Mac running;
    Red probe on pin 24 shows +12v. Passed.
    Red probe on pin 6 shows +3.3v. passed.
    Red probe on pin 3 shows +5v. Passed.
    Red probe on pin 10 shows +12v. Passed.

    It passed all the other checks so I'm a bit sceptical of Apple's somewhat blazé attitude towards the psu needing replacing when the fans don't spin when the power button is pressed. What if it's the power button? I seem to recall the power button units on these Macs have been known to cause sleep and power on/off issues. Or am I thinking of a different model?

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15 May 2, 2016