SETBLASTER wrote on 2023-07-05, 20:54:

So, i am opening this topic since i have a couple of motherboards (and video cards) that i really wish i could bring them back t […]
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So, i am opening this topic since i have a couple of motherboards (and video cards) that i really wish i could bring them back to pristine condition, and i don´t want these to break. Both motherboards are from the AthlonXP era/Pentium4 era. And you know how capacitors were bad during that time (like the silver caps used on Soyo brand that smell like cat piss). Plus a lot of heat during that time, a lot of OC, causing capacitors to bulge. and It has been more than 20 years, i think time is also a factor.

I did my calculations over digikey
Mounting type: through hole
temperature: -40C to 105c
Application :General purpose
Capacitance: Same as orignal
Voltage: same as original
Lead spacing: same as original
Diameter: same as original

Some of the questions i would like to know from you all since probably you have more experience at restoring old hardware:

1) I did not care at all about these 3 things, im not sure if i should:
"Ripple Current @ Low Frequency" , "Ripple Current @ High Frequency" , "Impedance"
should i choose something specific in there for motherboard use?

2) After doing all the price calculations:
a) A FULL motherboard recap using PANASONIC CAPS would cost about $31 to $35 dollars, Yay, expensive! but i like the motherboards
b) A FULL motherboard recap using RUBYCON CAPS, its cheaper, maybe it costs 2/3 of the Panasonic ones.
Which brand are you choosing? or you are choosing a mix to save money like Panasonic for the ones near CPU and other brands for the rest of the motherboard?, or you are going cheap mode on all?

3) Do you perform a FULL recap under these conditions? OR do you normally do a PARTIAL recap?
PARTIAL RECAP = would be buying new capacitors for the ones that range from 3300uf to 1000uf, leaving original caps that have smaller uf values like 470uf, 100uf, 220uf, 22uf, 10uf on the motherboard.
FULL RECAP = would be just trashing them all and buying new ones, because it has been 20 years. Bad cap era, even not visual bulged caps can be bad, etc etc.

i would really love to hear your comments, as im sure many of you are keeping some motherboards safe doing a recap, as some of them cost a lot of money now. even with smd caps on a voodoo 5500 cards.

thanks

Just on the voltage rating, it can sometimes be a good idea to bump it up a notch. E.g., if the board originally uses a 6.3V capacitor on a 5V supply then maybe use a 10V instead. Capacitor lifespan gets much longer than the rated lifespan if you stay well away from the maximum ratings. Oh, and check the height as well, otherwise they might clash with CPU heatsinks or components on cards.

I've done a few boards and others will have different opinions, but I generally::
1) Go with low ESR caps. The higher the resistance the higher the ripple and heat in the capacitor.
2) I usually order caps as an extra to a larger order, so I just go with what's in stock. I don't worry about brand too much (Panasonic and Rubycon are both good), but make sure you use a trusted supplier. Might be worth getting a component tester so you can measure the old caps before replacing them, and test the replacements before using them. There's a list of manufacturers on Tom's Hardware that looks reasonable:
https://www.tomshardware.com/reviews/power-su … 101,4193-5.html
3) If any of the larger caps look/test wrong then I generally just do all >470uF. I've just recapped a board where a 470uF near the PS/2 port had failed. Don't think I've seen smaller value through-hole ones on motherboards fail. I have seen small electrolytic surface mount ones fail on a floppy drive and a camcorder.

SETBLASTER wrote on 2023-07-05, 20:54:

1) I did not care at all about these 3 things, im not sure if i should:
"Ripple Current @ Low Frequency" , "Ripple Current @ High Frequency" , "Impedance"
should i choose something specific in there for motherboard use?

This depends on what capacitors you are replacing. If it's a general purpose cap, pretty much anything will work, but certain circuits require low ESR (in particular, for the VRM caps you want as low ESR as you can). This value is usually listed as "impedance" in the datasheet because at the specified frequency it is pretty much equal to the ESR, and it goes hand in hand with the ripple current.

Ideally you would find the datasheet of the cap you're replacing (not always an easy task, especially with crappy chinese brands) and try to find a replacement with similar ESR/ripple. If the datasheet doesn't specify those values or it's an 85C part then it's general purpose and any replacement will work. As a general rule, if the board is from the P4/Athlon XP era you want something like Panasonic FM, Rubycon ZL or equivalent for the big caps around the VRM. Boards from around 2005 and newer started using ultra-low ESR caps which are no longer being produced, in that case polymers are the way to go.

SETBLASTER wrote on 2023-07-05, 20:54:

2) After doing all the price calculations: a) A FULL motherboard recap using PANASONIC CAPS would cost about $31 to $35 dollars, […]
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2) After doing all the price calculations:
a) A FULL motherboard recap using PANASONIC CAPS would cost about $31 to $35 dollars, Yay, expensive! but i like the motherboards
b) A FULL motherboard recap using RUBYCON CAPS, its cheaper, maybe it costs 2/3 of the Panasonic ones.
Which brand are you choosing? or you are choosing a mix to save money like Panasonic for the ones near CPU and other brands for the rest of the motherboard?, or you are going cheap mode on all?

Rubycon and Panasonic are both very good, go with what's cheaper in that case. Personally I wouldn't go with unknown brands for non-VRM caps, but usually there is no need to get very low ESR parts for the small caps so you can use general purpose 105C Japanese caps if they're cheaper.

SETBLASTER wrote on 2023-07-05, 20:54:

3) Do you perform a FULL recap under these conditions? OR do you normally do a PARTIAL recap?
PARTIAL RECAP = would be buying new capacitors for the ones that range from 3300uf to 1000uf, leaving original caps that have smaller uf values like 470uf, 100uf, 220uf, 22uf, 10uf on the motherboard.
FULL RECAP = would be just trashing them all and buying new ones, because it has been 20 years. Bad cap era, even not visual bulged caps can be bad, etc etc.

I agree with the comment above. I usually do the >= 470uF on motherboards unless we're talking about abysmal stuff like Fuhjjyu or Chssi, that doesn't mean the smaller caps won't fail but in most cases they're not critical for correct operation of the motherboard.