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Gefagahaga 03-29-2011 11:48 AM

Broke something (a component like resistor or capacitator) when upgrading Mac Mini
 
1 Attachment(s)
Hello all!

So I was upgrading a Mac Mini Core Solo to Duo when I accidentally hit a small rectangle shaped thingy on the bottom side (i.e. the side facing the bottom) and it fell off.

The thing in question is called "C7598" and lies in the area underneath the R36 resistor and the CPU socket (inbetween those).

I've uploaded a pic of the area. You can see what has "fallen off" a bit to the left from the center of the pic.

So my questions are, what is this? Can it be soldered back on and if so, can I use the one that fell off or should I buy a new one? Which specs in that case?

Many thanks in advance.

cradom 03-29-2011 02:32 PM

Looks like a surface mount capacitor and I wouldn't recommend trying to replace it unless you know what you're doing and you're really good.

Gefagahaga 03-29-2011 02:59 PM

Well, what else can I do?

And it wouldn't be me doing it, would be a technician who knows how to solder.

Mac SK 03-29-2011 03:16 PM

Quote:

Originally Posted by Gefagahaga (Post 1210581)
Well, what else can I do?

And it wouldn't be me doing it, would be a technician who knows how to solder.

If theres enough of the old prongs sticking up you could connect a short wire lead to the new capacitor. They have to cover the board not to drop no solder and use heat sinks to protect other components.

chscag 03-29-2011 06:11 PM

The component C7598 is a surface mounted capacitor. It appears from the photo you provided that it broke off its mounting. The problem is not so much being able to solder it back but trying to find an exact replacement capacitor. You're going to need a schematic to find out what the value of it is. Also, those types of capacitors generally have a very close tolerance, perhaps + or - 1% which make it more difficult to find.

Gefagahaga 03-30-2011 02:42 AM

1 Attachment(s)
So its not possible to use the one that broke off? It looks whole (see pic).

RavingMac 03-30-2011 09:08 AM

Looks fine to reuse but need a deft hand soldering it back so you don't damage the board or other components.

chscag 03-30-2011 02:38 PM

Quote:

Originally Posted by Gefagahaga (Post 1210846)
So its not possible to use the one that broke off? It looks whole (see pic).

Yes, the capacitor looks whole but I can't tell from the photo you provided if there is anything left of the leads? If nothing is there and they broke off in the poly body, you won't be able to reattach it without possibly destroying the capacitor or ruining the board.

Surface mounted components generally have leads on the bottom. They may look like a small metallic area or tabs, and that's what gets soldered. However, the soldering process is done by machine. Actually a dipping process or surface mounting.

Gefagahaga 04-01-2011 11:29 AM

Wish I had a better camera, will try taking a couple of close up pics later.

Someone told me that these are probably something in Swedish called avkopplingskondensator, which can be translated as "decoupling" condenser/capacitors, hope you guys understand what that means (I don't). He said that they probably are 0.1uF.

Whats the worst case scenario if I successfully get it soldered back on but it doesnt "connect", i.e. the leads are damaged. Will the board suffer electrical damage or is it relatively safe to try?

Stanley 04-01-2011 11:44 AM

Just locate an electronics geek and have them resolder it. Don't do this yourself, no offense.

BrianLachoreVPI 04-01-2011 11:45 AM

Quote:

Originally Posted by Gefagahaga (Post 1212104)

Whats the worst case scenario if I successfully get it soldered back on but it doesnt "connect", i.e. the leads are damaged. Will the board suffer electrical damage or is it relatively safe to try?

Unless you have real experience in this - I wouldn't try to hand solder this at all. Not only is it a precise operation - but depending on the circuit - it's very easy to do damage that you can't even see due to excessive heat transfer. In otherwords - while soldering leads/legs/pins may seem easy - today's PCBs have multiple layers and very thin traces that can easily be damaged by heat transfer from a soldering iron. Additionally, even if the traces survive the heat transfer - there are sensitive components whose silicon junctions may be damaged. At any rate, I'd be very reticent to try this repair myself without the right equipment/skillset as well as a good idea of what the circuit was and what circuits are nearby.

John T 04-01-2011 11:50 AM

Looking at your photo of the capacitor, it doesn't appear to be damaged (capacitors of this type don't have leads, their connection to the circuit board are via the "pads" on each end.), in actual fact, they are very robust.

As has already been said, you need to locate somebody who is experienced with the use of a soldering iron - the circuit board is easily damaged if one doesn't know what they are doing!

In the most unlikely event of the existing component being faulty, once you know the value (any decent meter that reads capacitance will ascertain this) a new one will be readily available from any electronic component supplier.

Stanley 04-01-2011 11:53 AM

Quote:

Originally Posted by John T (Post 1212115)
Looking at your photo of the capacitor, it doesn't appear to be damaged (capacitors of this type don't have leads, their connection to the circuit board are via the "pads" on each end.), in actual fact, they are very robust.

As has already been said, you need to locate somebody who is experienced with the use of a soldering iron - the circuit board is easily damaged if one doesn't know what they are doing!

In the most unlikely event of the existing component being faulty, once you know the value (any decent meter that reads capacitance will ascertain this) a new one will be readily available from any electronic component supplier.

Chances are near 100% that the component and circuit board are just fine.

It's just a tricky, hair-splitting solder job. I did it once and it is way harder than normal everyday soldering. Which seems unfamiliar to you (no offense).

So you need a geek that has done this before, who will already have the correct tools, magnifying glasses on fixed mounts, and supplies.

John T 04-01-2011 07:05 PM

Quote:

Originally Posted by Stanley (Post 1212117)
It's just a tricky, hair-splitting solder job. I did it once and it is way harder than normal everyday soldering. Which seems unfamiliar to you (no offense).

Pardon? You seem to have completely missed the point of my post! Apart from correcting some misinformation regarding surface mount components, I was suggesting to the OP, in my opinion, his best course of action.

For your information, in the past, I have assembled a number of PCB's incorporating surface mount resistors and capacitors. Providing you know what you are doing and have the knowhow and correct tools, it's not too difficult.

Gefagahaga 04-02-2011 06:04 AM

Quote:

Originally Posted by Stanley (Post 1212110)
Just locate an electronics geek and have them resolder it. Don't do this yourself, no offense.

Quote:

Originally Posted by BrianLachoreVPI (Post 1212113)
Unless you have real experience in this - I wouldn't try to hand solder this at all. Not only is it a precise operation - but depending on the circuit - it's very easy to do damage that you can't even see due to excessive heat transfer. In otherwords - while soldering leads/legs/pins may seem easy - today's PCBs have multiple layers and very thin traces that can easily be damaged by heat transfer from a soldering iron. Additionally, even if the traces survive the heat transfer - there are sensitive components whose silicon junctions may be damaged. At any rate, I'd be very reticent to try this repair myself without the right equipment/skillset as well as a good idea of what the circuit was and what circuits are nearby.

Quote:

Originally Posted by John T (Post 1212115)
Looking at your photo of the capacitor, it doesn't appear to be damaged (capacitors of this type don't have leads, their connection to the circuit board are via the "pads" on each end.), in actual fact, they are very robust.

As has already been said, you need to locate somebody who is experienced with the use of a soldering iron - the circuit board is easily damaged if one doesn't know what they are doing!

In the most unlikely event of the existing component being faulty, once you know the value (any decent meter that reads capacitance will ascertain this) a new one will be readily available from any electronic component supplier.

Quote:

Originally Posted by Stanley (Post 1212117)
Chances are near 100% that the component and circuit board are just fine.

It's just a tricky, hair-splitting solder job. I did it once and it is way harder than normal everyday soldering. Which seems unfamiliar to you (no offense).

So you need a geek that has done this before, who will already have the correct tools, magnifying glasses on fixed mounts, and supplies.


No offense taken. As I mentioned in my earlier posts I'm not the one who's gonna do the soldering, I'll leave that to a pro.

My main concern was that I didn't know if a resoldering would be possible or if it would with most certainty ruin the whole board. With no other options in sight (other than just throwing away the whole thing) and with some of you saying it could be possible, I'm gonna have someone do the job and just try it.

Thanks for all the help everybody!


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