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Oct 30, 2007 3:27 PM
by: bobiemac66
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Posts:
9
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May 13, 2006
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20 inch ACD Inverter board question
Posted:
Aug 10, 2007 10:53 AM
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My display (20 inch ACD acrylic)recently showed classic symptoms for inverter board failure - dim top half of screen, 2 short, one long power light flash. I ordered a new board from We Love Macs and installed it - problem solved. Display powered up and worked perfectly - for about a day. When waking from sleep a day later, the old symptoms were back.
Obviously, We Love Macs doesn't want to believe their part is defective, and I admit it seems strange that a brand new part would fail so quickly. On the other hand, their price for the part is roughly half of some competitors, so I'm suspicious. And, I'm wondering what else could cause the problem, and would potentially zap a brand new board, if in fact that's what happened. Any ideas? Thanks.
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Posts:
3
From:
Vancouver, BC
Registered:
Aug 10, 2007
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Re: 20 inch ACD Inverter board question
Posted:
Aug 11, 2007 11:41 PM
in response to: kgsoto
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My 20" ACD started showing the dreaded symptoms 2 days ago: 2 short blinks followed by one long blink and a dimmed lower half of the display. If I turn off the Mac and disconnect and then re-connect the ADC connector, it will work again for a few days before dimming again.
I opened up the display and looked around inside. I noticed that the logic board inside the display has a Motorola microcontroller on board. My guess is that it monitors some attributes on the inverter board and then blinks the power-button LED if it senses something wrong. Disconnecting the ADC connector might reset the micro-controller, which may explain why the monitor works for a few days afterwards.
I'd like to know what exactly the 3-blink code means. In my case, it cannot be caused by completely failed components on the inverter board. Could the logic board's logic be wrong?
My second display is a 20" Viewsonic VG2030wm. It is as good as the Cinema Display and it can be bought for $250. It has a swivel base and it's height can be adjusted. In my opinion, the Cinema Display just isn't worth servicing and I certainly won't spend $599 on a new Cinema Display after my experience with my current one.
PowerMac G5 Dual 1.8
Mac OS X (10.4.10)
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Posts:
4,385
Registered:
Dec 23, 2005
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Re: 20 inch ACD Inverter board question
Posted:
Aug 12, 2007 8:38 AM
in response to: kgsoto
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What you describe could also by symptomatic of a failing CCFL (cold cathode flourescent lamp) in the backlight. And since replacing the inverter board didn't make the symptom go away, replacing the lamp would be the next thing to try.
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Posts:
9
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May 13, 2006
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Re: 20 inch ACD Inverter board question
Posted:
Aug 14, 2007 3:18 PM
in response to: BSteely
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BSteely - how hard is this to do? It looks like it requires installing 3 tubes, each with ends that need to be soldered. Have you done this before, or can you direct me to an on-line how to? Thanks.
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Posts:
4,385
Registered:
Dec 23, 2005
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Re: 20 inch ACD Inverter board question
Posted:
Aug 14, 2007 9:37 PM
in response to: kgsoto
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I did once replace the lamp in an original iBook. It was not easy. Especially since the bulb I got was not an exact fit (both diameter and length were wrong). The hardest part can be finding the right bulb(s) since they are not commonly sold. I can't really say for sure how hard the job is on a 20" Cinema since I have never tried.
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Posts:
9
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May 13, 2006
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Re: 20 inch ACD Inverter board question
Posted:
Aug 17, 2007 11:12 PM
in response to: BSteely
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Well, I've ordered the bulbs and have the how-to pdf from LCDParts/Moniserv. I'm more certain the inverter board is not the culprit. As a test, I shut down and disconnected the ADC connector from the card for a few moments then reconnected and powered up. The monitor is back to normal - for the time being. I read somewhere that the bulbs leak voltage as they age and the board can no longer strike the correct voltage.
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Posts:
3
From:
Vancouver, BC
Registered:
Aug 10, 2007
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Re: 20 inch ACD Inverter board question
Posted:
Aug 19, 2007 10:03 AM
in response to: kgsoto
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Your conclusion about the failing tubes make perfect sense. Could it be that there is nothing wrong with your original inverter board? My display has the exact same symptoms as yours.
Are these the tubes that you ordered: http://www.lcdpart.com/Products/ms264503.html ?
I removed the tubes in my monitor a while ago. It isn't hard, but you need to remove a lot of panels and screws as you already know. Also, they are very long and it may take some force to slide them in or out
I'm interested to know if the new backlights solved your problem. Would you let us know once you are done?
Thanks
Message was edited by: Acegryphon
PowerMac G5 Dual 1.8
Mac OS X (10.4.10)
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Posts:
13
From:
USA
Registered:
Oct 12, 2007
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Re: 20 inch ACD Inverter board question
Posted:
Oct 12, 2007 6:07 PM
in response to: kgsoto
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My 20" display is giving me the flashing power button of death  do you have any tips on the backlight replacement/how many there are, etc.?
Any information will be appreciated.
G4 Cube/Dual 867 MDD
Mac OS X (10.4.10)
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Posts:
10
From:
MD
Registered:
Sep 30, 2007
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Re: 20 inch ACD Inverter board question
Posted:
Oct 13, 2007 9:15 PM
in response to: bobiemac66
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The 20" Cinema requires 6 bulbs, 3 for the top and 3 for the bottom.
Dual 867
Mac OS X (10.3.9)
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Posts:
13
From:
USA
Registered:
Oct 12, 2007
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Re: 20 inch ACD Inverter board question
Posted:
Oct 14, 2007 7:04 AM
in response to: whocaresishare
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Thanks very much  is the flashing power button issue more often an Inverter Board, or bulbs?
G4 Cube/Dual 867 MDD
Mac OS X (10.4.10)
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Posts:
10
From:
MD
Registered:
Sep 30, 2007
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Re: 20 inch ACD Inverter board question
Posted:
Oct 22, 2007 3:59 PM
in response to: bobiemac66
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I have read some post where replacing the Inverter board has work and I have read where the bulbs and board need to be changed.
Dual 867
Mac OS X (10.3.9)
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Posts:
13
From:
USA
Registered:
Oct 12, 2007
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Posts:
3
From:
Vancouver, BC
Registered:
Aug 10, 2007
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Re: 20 inch ACD Inverter board question
Posted:
Oct 29, 2007 10:23 PM
in response to: bobiemac66
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I replaced the 6 tubes in my 20" ACD 4 days ago, and so far, it works perfectly. No more blinking power light: just a nice bright display. The parts are here: http://www.lcdparts.net/ccfldetail.aspx?ProductCCFL=MS264503
Installation involves carefully removing the old tubes and soldering the new ones in place. This can be tricky since the parts are delicate. I suggest using heat-shrink tubing over the solder joints to avoid any current leakage. Take your time and everything should be fine.
PowerMac G5 Dual 1.8
Mac OS X (10.5)
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Posts:
13
From:
USA
Registered:
Oct 12, 2007
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Re: 20 inch ACD Inverter board question
Posted:
Oct 30, 2007 3:27 PM
in response to: Acegryphon
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that's great....thanks for posting the details.
500MHz G4 Cube/Dual 867 MDD
Mac OS X (10.4.10)
Upgraded video all around/GigaDesigns CubeFan on the Cube, otherwise stock/ADC
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