Since you have the cable set already, that really is the best way to go about it. It will take some time and patience. If you decide to open up the monitor, this will also give you a chance to look around for anything else that may have gone wrong. A short caused by an incorrectly seated plug could be the problem, but it's troubling that the monitor shut down again when moved to a different power supply.
That said, here's what I can tell you about splicing in another power supply, without opening the monitor chassis.
You have 6 connectors on the power cable plug. The plug is not polarized and can be pluged in either way.
(The outer part of the plug connects to the grounded sheathing on the cable)
Inside the cable itself, there are only 3 connectors (plus the grounded sheathing). Red - 24v, Black - Gnd, Gray 20ga wire is 5v.
Once you strip back the insulation, There is a braided jacket surrounding the 3 wires. You can unravel the braid using needle nose pliers, or you can just push it down like a sock. Inside the braid there is more polyester insulation. You can cut this with scissors, but be careful not to cut the gray 5v wire - it's tiny.
You can power your monitor by supplying 24v DC to the red and black wires. They are about 16 ga.
The monitor will run happily on an alternate power supply, and it's an easy splice.
You can use something like this-
These power supplies will run cooler and more efficiently than the originals. That said, you'll make some obvious aesthetic concessions. So do some hunting. Any *regulated* 24V supply with at least 6.5 amps will work. Since you've already had some problems with the unit, it would be wise to add a 10 amp circuit breaker or fuse inline with your splice, to make sure your monitor doesn't overdraw due to some other problem.
Hope that's helpful- good luck!
Thank you very much for the detailed and excellent explanation. I just have a few questions about the splicing method, I know these are simplistic but bear w/ me:
1. Would BOTH the 24v and 5v cables connect to the positive DC output connections OR, would one go to the V+ and one to the V-? (For example, with something like this http://www.epbuddy.com/images/MeanWell/MeanWell_S350W15V_2_620px.jpg)
2. Would the Black ground wire from the monitor AND the ground of incoming AC power cable (which one can buy separately) BOTH connect to the singular ground connector on the power supply?
3. If the power supply says it has "overload / short circuit / over voltage protection" do you think I still need a circuit breaker?
4. When you say "They are about 16 ga." do you mean both wires take together are 16 gauge? And if so, what is the significance to this. Do you mean wrap the wires together for some reason?
Thank you very much sverstegen and looking forward to your reply.
Neutrinofield, sounds like you might want to have a buddy over who is good with this stuff to help sanity check the connections. It is important to get the right connections made, and you're dealing with mains voltage... a mistake could be dangerous and/or expensive. I wouldn't recommend doing a splice like this unless you're really comfortable with those risks.
1.) The red (+24) goes to the V+. The 5v wire would go to a separate, regulated 5v source. If you can find a power supply that does both 24v and 5v you'd be in great shape. But for now, you can leave the 5v wire disconnected. It stands to reason that this is to provide additional power for the USB hub.
2.) NO. Careful - wiring in the way you described will make blue smoke come out of your monitor. The black wire from the monitor goes to the V- on your power supply. The other three connections go to your AC input line and are not shared with any connections to your monitor. Hot (H) Line (L) and earth ground (the three lines) connect to the power cord coming in from the wall. You can buy a cord, or cut the end off of a standard 3-wire computer power cord. Like this one
3.) Yes, I would. The built-in overload circuitry in the power supply will only protect the AC power supply itself. You want to put a DC circuit breaker (or fuse) between the power supply V- and the monitor (after the power supply) to keep the monitor from drawing too much power.
4.) No, each wire should go to the terminals mentioned above. Individually they are about 16ga.
Good luck and be careful.
Hey! Glad to hear that!
I thought the circuit breaker would be useful in neutrinofield's situation, because he might have some recurring overdraw and need a resettable breaker. Since you're up and running, you might just use a fuse.
The original power adapter was meant to draw about 6 amps at full power. So you want to size your circuit breaker (or fuse) close to that. 6 amps is really the higher end of things, and it's an odd size breaker/fuse to find. If you don't run your display at full brightness, you should be fine with a 5 amp fuse/breaker. That'd give you about 125watts before the breaker resets, or the fuse blows. You could also hook up a kill-a-watt and see what kind of wattage you're consuming at normal usage.
That said, you could probably get by with a 10 amp fuse. But I'd aim for the smallest you can find between 5 and 10. You really just want to prevent a fire and limit damage if a short develops in the monitor.
When you go to purchase your fuses or breaker, just make sure they've got a DC rating for at least 24 volts. These are very common at auto parts stores.
Good luck! Enjoy your screen. Congratulations on the fix!
Dear Sverstegen, many thanks for posting the ACD pinout and sound advice! I've had to determine that myself a frew months ago.
Since you seem so technically savvy on the subject I am quoting my question from another thread here, hoping you might know the answer. The thread is this: https://discussions.apple.com/message/18176869?ac_cid=142432#18176869
A lot of people including myself have been trying in vain to identify Q1 on the mainboard of the A1081(20") and A1082 (23") ACD models. It seems to be a transistor, carrying an infamous SMD code, and is probably related to the 'detection line' or in any case to the secondary power supply circuit which is located on the mainboard. Failure of this transistor is probably the 3rd common cause of these monitors dying on us (and possibly related to the short-long-short error code), after "wrong powerbrick detected" (cause #1, error code short-long-short), and a defective/malfunctioning 3.3V LDO (LM1117, cause #2, may be even originating the error code in question here).
So: can anyone of you define either of the following SMD markings for a transistor: HEZH4; H6FU9; HEVQ9 or HFXS5? These, I gather, have all been found in the same aforementioned "Q1" position.
Quick update... My display failed a couple weeks ago- backlight dimmed out and I got the short-short-long error code. I think it's the power supply, though.
My multimeter indicates that it's only putting out ~20v, whereas it was doing 24 previously. It is kind of finicky about starting up too- the potentiometer that controls the voltage might be bad..? It makes a strange clicking noise when it actually engages, and when you try to adjust it upward, it makes a rapid clicking noise. This is the same one you linked in your post. What would you recommend that I do at this point?
Thanks again for the info you gave me!
Bummer! Sorry to hear that. I agree- sounds like the PSU is on it's way out.
Losing 4v would be a big drop, and more than enough to cause a failure in the backlight.
Small thing worth checking - is the input voltage switch set to 110 or 220v? I think they come preset to 220v, and you'd need to change over to 110 if you're in the states. When the input voltage is wrong, you lose most of the trim from the adjustment pot. If this is set correctly and you're still getting weird behavior, time to dig a little deeper.
Check and re-check all the PSU wiring.
Inspect the PSU capacitors for physical abnormalities- (bulging or leaking fluids). Google image search "bulging capacitor" for reference. Most of the time these will fail at the top, but I've seen them leak from the bottom too, so keep an eye out for subtle damage. Yours is probably going to be slight if you're still getting somewhat normal operation.
Finding a faulty set of capacitors can help you put the nail in the coffin, and move on to a new PSU unit. That's really the easiest, safest thing to do at that point. They're cheap and plentiful, and normally pretty resilient (unlike the miniaturized Apple power bricks).
But, if you're patient and feel comfortable with a soldering iron you can replace them yourself and fix the unit you've got.
PSU's will have several large (read:dangerous) capacitors on the main board. You need to discharge them before you can safely work on the unit. Here's an article that talks you through it http://www.wikihow.com/Discharge-a-Capacitor. Also Google "PSU capacitor replacement".
When hunting down the replacement caps, make sure to get the same farad value, but know that you can get an equal or higher voltage rating. http://www.mouser.com/
Be careful. Good luck in round 2 !
I checked it out for bad caps, and they all seem ok- I think I'm a bit more comfortable with getting a new PSU. The voltage was set wrong when I got it initially (220), but I had switched it before I ever turned the thing on. When I opened it up, though- I did notice that the switch component was very, VERY rusty....
Anyway, at this point, I think I want to just replace the PSU- this one was 20 bucks or so anyway, so no big deal there. Any recommendations on a new PSU?