ways to tell if capacitors are about to go?

[naryasece]

Hi all,

I had a little trouble booting my PowerBook 2400c tonight, though I did get it to boot normally. However, I detected a faint burning smell and now the area around the power plug has a strong chemical odor (hoped it was just the battery). Oddly enough the smell reminds me of some paints I used in elementary school...

Is it a sign that the capacitors need replacing? Or might it still be safe to use? I have my fingers crossed that it is nothing serious, my 2400c is my favorite and one of the few Macs I have left that is not plagued by some issue.

Thanks for reading!

 

[uniserver]

I would say, use it till it burns up, then only replace the one that has gone bad,

Its nice because the cap that goes bad has a built in detection system, (it will look crispy)

I changed a chard Tantalum Cap on the LB my powerbook 170 mainboard, the cap was on the underside of the LB, very close to the power plug. This was one of those (does not work 99 cents plus shipping ebay finds)

Also real quick, make sure to use a multimeter, and make sure your power supply is outputting the proper voltages.

 

[naryasece]

Ah. Thanks for the tip! Maybe I'll grab my multi meter and measure the voltages across them and see if I can measure any degradation over time. Of course, a blown cap will make it easy to spot what needs fixing!

 

[Byrd]

Most common cause of failure is blown thermal SMT fuses on the Powerbook 2400c - resulting in the "green light of death", over time. There are several thermal fuses on the motheboard that can can fail, I recall mine had 2 out of 4 that needed replacement, and I had to do it again when I used an original Apple Duo charger on it once (DON"T use, just use a charger designed for a Powerbook G3).

 

[beachycove]

I've been using a Duo charger (the highest-wattage one, came with a 2300c) on my 2400c for a couple of years, with no ill effects.

Is this documented elsewhere/ somewhere?

 

[naryasece]

My understanding is that as long as the power adapter meets the voltage and minimum amperage, any higher amperage is fine for the computer. Using a power adapter with too high voltage will damage the electronics, but the electronics will only use as much amperage it needs.

Of course, in some circumstances, using a power adapter that does not supply enough voltage/current could be damaging because the electronics will demand more power than the adapter can supply. The exception are devices designed to work with varying voltages (ie AA alkaline batteries).