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Do you guys use those pink/salmon colored washers?

K

Ken90630

Golden Member
I've wondered about this for awhile:

Do you guys use those small colored fiber washers when you screw a motherboard down onto the case standoffs? If so, why? And if not, why not?

I've never fully understood their purpose, but I've read it's to provide a slight cushion to prevent the screw from 'grabbing' the mobo surface & cracking it when screwing the board down. Is that correct?

For discussion purposes, my question applies to current/modern mobos with those little raised dots of silver solder that ring around the screw hole on mobos.
 
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Always thought they were paper azzholes...? :biggrin:


But yes your right back in the day with the original old old stuff (486, Pent 1`s and such) they were supposed to be used to cushion the head of the screw against the board surface to prevent it from cracking the PCB... Later designs in boards put those little dots as you say but dont think they are silver solder but just reg solder which is somewhat soft and does the cushion job and helps lock the screw in place... Also they use the solder to secure the reinforcement rings that have been added to newer boards... I have a ton of those little paper buggers and even have several bags of the old plastic standoffs of various types too the ones that threaded into the case and the motherboard just snapped down on them...
 
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Ken90630 said:
I've wondered about this for awhile:

Do you guys use those small orange/red colored fiber washers when you screw a motherboard down onto the case standoffs? If so, why? And if not, why not?

I've never fully understood their purpose, but I've read it's to provide a slight cushion to prevent the screw from 'grabbing' the mobo surface & cracking it when screwing the board down. Is that correct?

For discussion purposes, my question applies to current/modern mobos with those little raised dots of silver solder that ring around the screw hole on mobos.
Click to expand...

Fiberglass reinforced epoxy PC board material is strong enough to resist damage. Therefore the only purpose of the cardboard washers is electrical insulation, to prevent shorts to chassis if any copper areas carrying power or signals run too closely to the mounting screws and standoffs. Install washers as needed. The copper donuts dotted with solder are ground points and don't need to be insulated.
 
BTA said:
Not since 1999
Click to expand...

What happened in 1999? Was there a new standard or procedure introduced -- or maybe the implementation of those raised dots of solder? I wasn't very 'into' computers in 1999, so forgive my ignorance here.
 
Some old motherboards would run traces right next to the mounting holes, so the washers were sometimes quite necessary. (There is soldermask over the face of the board, which provides insulation, but it could be scratched off by a turning screw.)
Any new board I've worked with has adequate space around all mounting holes; some even appear to use the mounting holes as an extra way of grounding portions of the board.
 
I wasn't exactly sure when they should be used (though I probably would have come to the correct conclusion had I thought about it carefully), but I was aware that they were not necessary in the vast majority of cases. Knowing that, I never used them because they are just ugly and extra parts to deal with. I have seen clear ones before which I'd get if I had to.
 
I almost always use them on the bottom side of the board between the standoff and board...just makes me feel better knowing its cushioned and wont short out to the case..
I had a board about 3 years ago that if i didnt use them it wouldnt boot..so i use them always on my personal rig...I guess you really dont need them but ive been building computers since 1996 and and always used them back then, its just me but I feel safer using them..
the mounting screws come down on the board and touch the solder dots so the board is grounded to the standoffs..this is just me and i do believe they are not needed on the boards these days....
 
I still use them.... though I've never really known why.

If someone's getting paid to make them, and put them in that tiny bag, the least I can do is use em 😀
 
You are not suppose to use them on the boards that have a solder ring around the bottom of the hole. The idea is that when you screw down the board it makes a solid ground connection to the case. The case then becomes a ground plane for the back of the board so any EMI or RF emitted doesn't interfere with other devices on the board or outside the case.
 
Modelworks said:
You are not suppose to use them on the boards that have a solder ring around the bottom of the hole. The idea is that when you screw down the board it makes a solid ground connection to the case. The case then becomes a ground plane for the back of the board so any EMI or RF emitted doesn't interfere with other devices on the board or outside the case.
Click to expand...

The case is already a ground plane, regardless of the motherboard attachment. Grounded through the power supply chassis, to the ground pin on the power cord, to the earth ground.

The screws to the standoffs just help to tie all ground points together.
 
SparkyJJO said:
The case is already a ground plane, regardless of the motherboard attachment. Grounded through the power supply chassis, to the ground pin on the power cord, to the earth ground.

The screws to the standoffs just help to tie all ground points together.
Click to expand...

Ground planes hit with RF or EMI can actually work as reflectors that rather than absorbing the energy deflect it causing other circuits to misbehave. Placing ground points around the board connected to the ground planes helps to prevent that behavior. That is why on RF gear a shield is soldered around the entire perimeter to ground vs just being tied to it on one corner which would be much easier for engineers to do in layouts.
 
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