Router cap replacement causes hotter chips???

[bw1]

Curious... replaced the only 2 caps (220uf/25v 8x12mm-ish G-Luxon's) in a WRT54G v2 with Samxon GT's that I had laying around, and the two main chips on the board run hot to the touch. Out of curiousity, I put the G-Luxon's back in, and the chips then run slightly warm to the touch.

Is this a normal result? I'm guessing not a good choice for replacement, but I've read many posts where Panasonic FM were recommended, so figured a "Low Impedance" GT would be just fine.

The ripple on the originals was right around 200-300mA (exact size not on data sheet) and the GT is 640mA, so that shouldn't be a problem...

Help me learn

[digge]

Re: Router cap replacement causes hotter chips???

Could you please complete all the numbers and letters, would make it easier to understand what you replaced with what.

What series G-Luxon was originally there?
You replaced with Samxon GT but didnt specify what voltage, cansize or even if you changed the uF as well.

Im no expert on the subject but yes, changing values can make your unit run hotter, depending on the design and what purpose the caps had and so on. In general try to stay as close as possible in ESR, ripple and so on to the originals.

[Per Hansson]

Re: Router cap replacement causes hotter chips???

What digge said, plus measuring temperature differences with your index finger is not in all circles considered scientifically accurate testing

[NxB]

Re: Router cap replacement causes hotter chips???

[quote]The ripple on the originals was right around 200-300mA (exact size not on data sheet) and the GT is 640mA, so that shouldn't be a problem...[quote]


Aren't you saying that the ripple from the GT is twice the originals? The WRT54g run pretty hot and need a small HS on the broadcom chip anyway. All mine run hot to the touch caps replaced or not.

[bw1]

Re: Router cap replacement causes hotter chips???

The originals were:

G-Luxon, SM series
220uf/25v
8x11.5mm or 8x12mm
The only other markings on them besides 105*C is that one has "311B(M)" and the other has "312B(M)".

The SM data sheet only lists a 10x12.5 size, @250mA ripple, but judging from the other ripples above and below 220uf, I expect the original ripple to be 200-300mA.

These were replaced with Samxon GT series, 220uf/25v/0.13/640mA 8x12mm.

[TBoneit]

Re: Router cap replacement causes hotter chips???

What digge said, plus measuring temperature differences with your index finger is not in all circles considered scientifically accurate testing

I use that exact same type of digital probe all the time. If it is hot enough to burn or cool to the touch I can tell.

[bw1]

Re: Router cap replacement causes hotter chips???

OK, OK, so it's not scientific... but it IS pretty easy to tell if something is just warm to the touch or hot. And by hot, I don't mean going-to-burn-up, just noticeably hotter than it is with the originals.

[yyonline]

Re: Router cap replacement causes hotter chips???

Unless you know the load on the router's CPU at the time, it doesn't really tell you anything. The CPU load can vary quite a bit depending on what's going on with the network on my WRT54G running Tomato firmware. It's not the most powerful router in the world, and it doesn't take a whole lot to load the cpu.

I've recapped enough of those and the factory caps are all over the map as far as specs go. The best spec factory caps I've seen were Su'scon comparable to Panasonic FM, so I usually use FM as replacements in the WRT54G routers. Never had any issues with any of the routers I've recapped with the FM.

[bw1]

Re: Router cap replacement causes hotter chips???

Router was running stock firmware and should have had virtually no load after initial boot-up, as it wasn't hooked up to any networks/devices other than one computer to load the config pages.

By the sound of it, these things shouldn't be picky, so I'll probably just re-do it and see what happens.