125 Degrees Capacitor's

[rarack22]

Hi all, new here. Still learning. Used to working on Wii's Xbox's etc... and repairing traces but just starting on capacitor's.
I think I have figured everything out except my capacitor's on my board are listed as 125 Degrees CH. I can not find any capacitor's rated at 125 Degrees, 105, but not 125. Should it be safe to replace most of the board with 105's? That is all I am trying to figure out.
I have a Gateway HD2400 monitor. The monitor works great except the touch sensitive menu does not work most of the time and is unreliable. I have tested the thin ribbon and it checks out fine. I am assuming it is the capacitor's on the video card located by the ribbon connector. Especially now that I found out the capacitor's are Su'scon. A few are SAMXON but I figure why not replace them all while I am at it.
47UF 16V
10UF 25V
100UF 10V
22UF 16V
These are the ones nearest the ribbon connector. I am going to chart the rest of the capacitor's tomorrow. If anyone could shed some light on the 125 Degrees CH I would be more then appreciated. I have searched for a few days now, here and other places on the net. Hands down this is the best site I have found and look forward to getting to know it. Thanks all who may post there thoughts.

[japlytic]

Re: 125 Degrees Capacitor's

Welcome, rarack22!

Replacement of 125C units with 105C units depends on the circumstances, which includes being near hot areas and/or areas with poor ventilation.

Here is a list of manufacturers and series of 125C (or higher) electrolytics:
Nippon Chemi-Con: GXE (2000-5000 hours), GPA (3000-5000 hours), GXL (5000 hours), GXH (1500-2000 hours - 135C)
Nichicon: BT (2000-10000 hours), BW (2000-3000 hours - 135C), BX (150C)
Rubycon: ZT (1000-4000 hours), RX50 (1000 hours - 150C), RX30 (1000-4000 hours - 130C), HBX (4000 hours), HRX (3000 hours)

Depending on board space, you can upgrade to higher voltage units if lower voltage units are not available in a lower capacitance (e.g. 47uF 16V are not available, but 47uF 50V units are available).

[M98Ranger]

Re: 125 Degrees Capacitor's

Sorry for the resurrection, but I felt like I had something important to add.

It's nothing new, but if the design was for a higher temperature (125C for instance), it was for a reason. As an engineer myself, another engineer wouldn't specify a temperature rating of 125C just to make the design more robust. It's all about cost and matching component life of all the components together so that the 'weakest link' breaks at about the same time as all the other components.

That said, if you increase the rated voltage, most people understand that there is an increase in ESR, which is correlated to an increase in temperature due to inefficiencies, etc.

So the IMPLICATION that I am trying to point out is that;

1. If 125Celsius is a design temperature (and it most likely is ...especially taking into account the enclosure of the Xbox)

and

2. If you reduce that sustainable temperature to 105Celsius

and

3. If you try to correct for the reduction in temperature by increasing the voltage rating...

4. Then you are going to overheat the capacitors and LIKELY blow them turkeys out long before their "TIME" was INTENDED to come.

2 Cents worth from a Mech Eng.

[larrymoencurly]

Re: 125 Degrees Capacitor's

Why did my parents' ancient RCA top loader VCR (by Panasonic) contain so many 125C capacitors?

[cashkennedy]

Re: 125 Degrees Capacitor's

Because VCR was first used for porn, and things could become hot / and or steamy fast.

In regards to the actual issue, most low esr caps are rated for longer life / and higher temps then regular general purpose caps. The device that has the 125C caps probably chose the cheapest low esr cap that matched some other specs they wanted. Cap life expectancys are time at max temp, almost no devices ever built are running at 105 or 125C very close to the capacitors. (Except maybe ATI x19xx video cards . But by going with a 125 C cap and running it at half that temp, you can get maybe four times the longevity out of the capacitor... so instead of 2000 hours (under 1 year of use) you get 8000 hours... If caps only lasted their life rating wed have some serious work to do, cause ive almost never seen any rated for over 10,000 hours, and have seen many devices plugged in for 20 years / and or running for that long...