in the G5 imac model...
If not then this will maybe help..
Symptoms:
If you're Imac G5 is suffering from power problems (not turning on, standby issues, video problems and scrambled pictures. Maybe its time to check those capacitors on the motherboard)
Checking those caps is easy and takes 2 minutes: Follow step 1 and 2, and step 7 and 9 to know what to look for...
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Signing UpStep 1: The Imac...
Our victim: A "left to die" Imac G5 17." We are going to save him in a Saturday afternoon.
Here are some things we need to help him:
A LOT of space... We need to store all his parts temporary and we have to work on its motherboard.
It also keeps things organized.
Tools: These are the tools that I used:
soldering iron, screwdrivers, torx screwdrivers, anit static band, pliers, thermal compound, and replacement capictors.
Experience: Please have some, Its not difficult, but I think some is defiantly required.
Safety warning: Always unplug the power!! Even when the power is unplugged some capacitors will remain there power! In the new Imac models these power supply units on the bottom are open, and you WILL get a high voltage shock from it!! This is not the case here but be advised, if you see something and you have no idea, just stop and ask someone who does knows!
Capacitors: The ones that we are going to replace are bulging and could spit out electrolytic fluid or residue. (In fact, mine did when pulling them out...) Clean of this stuff from youre hands and the motherboard immediately!!! And wear safety goggles, the old capcitors are under heavy pressure, if they burst right in your face then... Well, youre not becoming any more attractive from it...












































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The power supply probably needs recapping at the same time.
Iam happy to see that a lot of people are using the instruct to repair there broken imac's, giving them a second live.
Many thanks to you all...
My old, little soldering iron was not up to the task as it could not deliver enough heat to release the old caps. I bought a 140 watt solder gun and still had to hold it there for 10 seconds to get them out, but it worked.
I heated the the blocked holes and pushed on the new caps and slide them in one leg at a time until they were seated. Then again gave them a good blast and another drop of solder with the solder gun.
The one thing I missed was refitting the left grey piece (inverter unit). I had connected the two cables but missed the four pin socket as I had not seen that on the dismantle. Once refitted correctly the machine seems to be up and running.
thanks...phil
You however *MUST* use caps of the same capacitance (eg 1800uf == 1800uf)
Keep in mind your PSU may also have quite a few popped caps, if you are more skilled I would check it out as well.
For the PSU, gently scrape the gray epoxy away from the bused caps without scratching or bending the coils.
They need to be good brand, Rubycon, Nichicon, Panasonic, Sanyo etc and also must be the correct series to ensure they have correct ESR and Ripple current rating (Check the datasheets of the old and new capacitors)
Also, do NOT use a drill to clear VIAs, you can very easily destroy the plating and ruin the board.
If you must use something, the BLUNT end of the drill, while applying heat to the joint and push the solder out.
Do NOT drill using the sharp end while the solder is cold.
http://www.thecapking.com/applg5.html
But iam not sure what to do with 25 caps?
Same thing here:
http://applefactors.us/Capacitor_Repair_Kit_For_Imac_G5_Logic_Board_20_17.html
I think you should order those things separately and not as a kit, its probably the most cheapest way to do it. Just take same values and if your budget permits it: Take caps that can take a bit of heat to prevent this from happening again!!
It gave us the opportunity to see a "naked" G5 As well !!!
I've changed capacitors in PC motherboards a lot of times, and the tricky part is desoldering the old ones.
I have a method: Use a 60Watts soldering iron, applied to BOTH legs of a given capacitor at the same time.
Let It heat for 10 seconds.(It´s a bad capacitor...You can't ruin It!).
Then, SLOWLY, pull the capacitor out of the board while applying heath.
To open the pad orifice where the capacitor lead was , use the copper "tail"....it is a hard way, but It is worth the effort.
If the orifice doesn't clean at your satisfaction, then use a drill bit of the right size (0,5 mm is ok ) ..but use it BY HAND..make a handle for it with some isolating tape!
One thing I do not agree with You is: "put same rate capacitors"
The "capacitor maladie" is due to capacitors that are rated up to 85°C of temperature.
I always use as a replacement capacitors of the same rating in microfarads (uf) AND volts , but capable to withstand 105°C of temperature.
The difference in price is negligible.
Thanks again for the photos.
I've used it for almost a minute and no pun for the traces of the motherboard.
You must realize that you are trying to unsolder a BAD capacitor (You can't ruin It MORE) and It's soldered onto the positive and negative huge planes of the power supplies....It's A LOT of copper that will dissipate the heat and , if You use less than 60W this will be a real problem....You risk of pulling a capacitor's leg that is yet well attached to the internal pass-trough-holes copper due to a "cool" soldering tip. Bad thing, I prevent You...
I have, once , used a 100W soldering iron (from a friend) and...well.....each damaged capacitor was out of the board in less than 5 seconds!!
Last sunday, I used a "solder sucking" device (I don't know how It's called in english), along with the 60W soldering gun....I was able to "unclog" the orifices in a matter of seconds.
I used a new approach to hold the mother board:
I made a "vise" with two 10inch "L" shaped plastics, almost 10 inches long, too, attached to my table with grips, and sandwiched between them the motherboard with two pieces of foam.
The board remains vertical, firmly held by the jig, and then You can use both hands, one for the soldering gun, and the other to pull softly the capacitors out, or to use the "solder sucking" device", one from each side of the board....I think I will make a permanent jig for that!!!
Nice year for everybody!
And that solder sucking device, I know them as desoldering bulb or pump depending on the type. But in a pinch you can also make your own solder braid with some copper wire and flux to wick away old solder.
Anyways good luck to you Asmodeo!
I agree with you about using higher temperature caps, because that is one of the reasons why we are replacing those caps in the first place.
though i havent run into this issue since i was running socket 7s
Again thank you.
Good luck repairing your Imac(s)...
The capacitor plague is a source of frustration and wealth to us all ;) I personally ow my flatscreen to this disease and a dead flatscreen is just as easy as with the iMac.
although i don't need them many other migth need them
(some dodgy-spelling, might benefit from a re-read?)
L
on the other hand ceramic and polyester capacitors is not easy at all to identify whaich are broken