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HELP - Broken SMD Capacitor #qmx

 

Good morning Group,
?
Hoping for information and validation of a proposed repair for a problem I created while assembling my new QMX kit.
?
I cracked SMD 0603 capacitor C513 (its in the TXBias input area of the Low Pass Filters section).
It looks like a typical by-pass capacitor to me, BUT I am not an EE or talented RF designer.
I was able to float it off and cleaned up the solder pads.
?
I wanted to see if anyone could give me the basic specs (tolerance and V rating)

AND . . .

Get opinions/advice on whether I could replace that component with a small, regular 0.1uf ceramic capacitor with lead wires. I ordered a 10 pack from AdaFruit of common, 0.1uf bypass capacitors (+/- 20% - 50V), I'd preform the leads, insulate with quality shrink tubing, tape the component down and then tack and solder the leads to the pads. Figured I'd add a drop of hot glue to the 'face' of the component to make sure it stays flat on the board during the rest of the kit assembly, and getting everything in the enclosure.?

I'm almost certain I can solder the leaded component onto the pads and have it lay flat in a nearby empty area, rising above the board at no more than 2 - 2.5 mm.
I'm not so sure I can successfully solder in a replacement? 0603.? 74 year old eyes, hands and fingers aren't what they used to be. I do have a good soldering irons and a magnifying headlamp (up to 15X) and can still assemble, modify and repair tiny through-hole component 'stuff' pretty well.?

All info, opinions and suggestions are welcome.

73?
Greg - KI4NVX
 

Hi Greg,

Soldering an SMD component like a capacitor is relatively easy.? It would be easier for me to use an SMD than a leaded component.? I put a small dimple of solder on one of the cleaned pads and tacked the part in place using a fine tweezer to hold the part.? I solder the other side, then go back and touch up the first side.

You are correct that the capacitor is a bypass and not critical.? Any ceramic rated for better than 15 volts should be fine.

73
Evan
AC9TU
 

Greg, I think that is a garden variety 100nF X7R 50v capacitor.

?Yes, you can replace it with a leaded capacitor, but with caution.

?The adhesion of the pad traces to the board can easily fail when attaching a leaded component where an SMD should be. Any attempt to form or bend one lead after the other has already been soldered may result in damage. You might lift the pad and trace up off the board.

Replacing the damaged capacitor with another SMD is the better solution IMO.

JZ KJ4A?

On Wed, Mar 6, 2024, 9:21?AM Greg McCain via <gamccain50=[email protected]> wrote:
Good morning Group,
?
Hoping for information and validation of a proposed repair for a problem I created while assembling my new QMX kit.
?
I cracked SMD 0603 capacitor C513 (its in the TXBias input area of the Low Pass Filters section).
It looks like a typical by-pass capacitor to me, BUT I am not an EE or talented RF designer.
I was able to float it off and cleaned up the solder pads.
?
I wanted to see if anyone could give me the basic specs (tolerance and V rating)

AND . . .

Get opinions/advice on whether I could replace that component with a small, regular 0.1uf ceramic capacitor with lead wires. I ordered a 10 pack from AdaFruit of common, 0.1uf bypass capacitors (+/- 20% - 50V), I'd preform the leads, insulate with quality shrink tubing, tape the component down and then tack and solder the leads to the pads. Figured I'd add a drop of hot glue to the 'face' of the component to make sure it stays flat on the board during the rest of the kit assembly, and getting everything in the enclosure.?

I'm almost certain I can solder the leaded component onto the pads and have it lay flat in a nearby empty area, rising above the board at no more than 2 - 2.5 mm.
I'm not so sure I can successfully solder in a replacement? 0603.? 74 year old eyes, hands and fingers aren't what they used to be. I do have a good soldering irons and a magnifying headlamp (up to 15X) and can still assemble, modify and repair tiny through-hole component 'stuff' pretty well.?

All info, opinions and suggestions are welcome.

73?
Greg - KI4NVX
 

I agree now too JZ.

I like Rowan's suggestion for the temporary holder too.

Going to experiment with holding and putting the busted one in place while I wait for my DigiKey order to arrive with fresh ones.

Greg KI4NVX


On Wed, Mar 6, 2024 at 11:24 AM, John Z
<jdzbrozek@...> wrote:
Greg, I think that is a garden variety 100nF X7R 50v capacitor.

?Yes, you can replace it with a leaded capacitor, but with caution.

?The adhesion of the pad traces to the board can easily fail when attaching a leaded component where an SMD should be. Any attempt to form or bend one lead after the other has already been soldered may result in damage. You might lift the pad and trace up off the board.

Replacing the damaged capacitor with another SMD is the better solution IMO.

JZ KJ4A?

On Wed, Mar 6, 2024, 9:21?AM Greg McCain via <gamccain50=[email protected]> wrote:
Good morning Group,
?
Hoping for information and validation of a proposed repair for a problem I created while assembling my new QMX kit.
?
I cracked SMD 0603 capacitor C513 (its in the TXBias input area of the Low Pass Filters section).
It looks like a typical by-pass capacitor to me, BUT I am not an EE or talented RF designer.
I was able to float it off and cleaned up the solder pads.
?
I wanted to see if anyone could give me the basic specs (tolerance and V rating)

AND . . .

Get opinions/advice on whether I could replace that component with a small, regular 0.1uf ceramic capacitor with lead wires. I ordered a 10 pack from AdaFruit of common, 0.1uf bypass capacitors (+/- 20% - 50V), I'd preform the leads, insulate with quality shrink tubing, tape the component down and then tack and solder the leads to the pads. Figured I'd add a drop of hot glue to the 'face' of the component to make sure it stays flat on the board during the rest of the kit assembly, and getting everything in the enclosure.?

I'm almost certain I can solder the leaded component onto the pads and have it lay flat in a nearby empty area, rising above the board at no more than 2 - 2.5 mm.
I'm not so sure I can successfully solder in a replacement? 0603.? 74 year old eyes, hands and fingers aren't what they used to be. I do have a good soldering irons and a magnifying headlamp (up to 15X) and can still assemble, modify and repair tiny through-hole component 'stuff' pretty well.?

All info, opinions and suggestions are welcome.

73?
Greg - KI4NVX
 

Greg, You can do this! I'm in the same boat as you. I'm 70 now and my eyes aren't those of a teenager anymore. But with a set of magnifiers sitting on my head and really good light, even I can solder SMD parts. I just practice on a scrap PCB until I can make a quick clean joint as described above. It helps to pin down those little buggers (603s) with tweezers then when the solder melts on one side the part will settle nice and flat to the opposite pad. After that a little solder on the tip of your iron will wick right into place to attach the other side. Just to be sure, I keep my tweezers on top of the part and reheat the first tack. Done.? ?

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