Need help! Parallel Cap...

[kids]

I'm repairing mainboard with bad PS/2 ports. I try to replace a parallel cap (near PS/2 ports ). Cap sign C221, please tell me that is C-apcitor 221-22x10^1=220 picofara, is that ?

And I dont find any the same Cap with 221, just only C181. So can I replace C221 with C181?

Thanks.

[Rainbow]

Re: Need help! Parallel Cap...

If it's shorted, remove it and test without it. It should work. If it does not work, something other is bad too (probably super i/o chip). If it works, use that C181.

[gg1978]

Re: Need help! Parallel Cap...

C221 is just the parts designator of the part.. it does not mean 220uF or pF.. And do not replace C221 with C181... Is this a small SMT type capacitor, or a radial leaded electrolytic??

[willawake]

Re: Need help! Parallel Cap...

good point. just show some pics so everyone is not confused...

[Rainbow]

Re: Need help! Parallel Cap...

I guess it's small SMD 4 capacitor array in 1 (like the resistor arrays). It's present on some boards near the PS/2 ports - and its 4 capacitors are connected between the 4 PS/2 lines (mouse clock and data and keyboard clock and data) and GND. I've seen it bad once, resulting in non-working PS/2 ports.

[kids]

Re: Need help! Parallel Cap...

I guess it's small SMD 4 capacitor array in 1 (like the resistor arrays). It's present on some boards near the PS/2 ports - and its 4 capacitors are connected between the 4 PS/2 lines (mouse clock and data and keyboard clock and data) and GND. I've seen it bad once, resulting in non-working PS/2 ports.

You are right! Some (or almost) mainboard use single cap for 4 PS/2 lines, we can replace each cap if it go bad. But with SMD 4 capacitor array - as you type - we must to replace if only 1 of 4 is bad.

But I cant find any other C221, but in my hand, I just have C181. I can not replace each other, can I? So bad!

[gg1978]

Re: Need help! Parallel Cap...

You are right! Some (or almost) mainboard use single cap for 4 PS/2 lines, we can replace each cap if it go bad. But with SMD 4 capacitor array - as you type - we must to replace if only 1 of 4 is bad.

But I cant find any other C221, but in my hand, I just have C181. I can not replace each other, can I? So bad!

Ok, this is making a bit more sense now.. Chances are you can try unsoldering the part, and seeing if it'll work without it.. You may try plugging your PS/2 keyboard into the PS/2 mouse ports, as some boards allow you to do this (intel OEM motherboards especially).. If not, buy a scrap board to steal the part from.. There's a forum here where people see if others have parts they want..


Also, this cap array is probably protecting both the ports in the PS/2 connector, as each PS/2 only has two data lines..


What kind of motherboard is this??

[kids]

Re: Need help! Parallel Cap...

My board is MSI (MS5187 VER:1).
But I want to know I can replace C221 with C181, yes or no.

Thanks

[gg1978]

Re: Need help! Parallel Cap...

I suppose you can certainly try it.. You do run the risk of damaging the board more from improperly soldering SMT devices.. I'd highly recommend practicing removing and replacing SMT parts on a scrap board before you try to swap the cap arrays on the 5187..

Chances are that you will end up disabling some other part of the motherboard by stealing C181 and placing it in C221's position.. Cap arrays can have the internal caps wired up in different ways, either straight thru, or in a bus configuration, or a mix..

[kids]

Re: Need help! Parallel Cap...

I suppose you can certainly try it.. You do run the risk of damaging the board more from improperly soldering SMT devices.. I'd highly recommend practicing removing and replacing SMT parts on a scrap board before you try to swap the cap arrays on the 5187..

Chances are that you will end up disabling some other part of the motherboard by stealing C181 and placing it in C221's position.. Cap arrays can have the internal caps wired up in different ways, either straight thru, or in a bus configuration, or a mix..

Keep peace your mind! I replaced array cap and array resistor for many times. But this time I cant find any other C221. Which array cap I can replace same with C221?