Funny smell Apple IIe power supply

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Joined: Apr 24 2012
Posts: 251

I recently got an Apple IIe enhanced from a friend who asked me to clean for him.everything went fine, but while trying to run a diagnostics program I thought my wife was cooking, a sweet burning smell began to come out. I then realize it was the IIe, and immediately shut it down. Mi afraid to turn it on again, what can it be? Can it be repaired?
Ranks in advance.
Javster

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Joined: May 27 2013
Posts: 794
Re: Funny smell Apple IIe power supply

The problem may be that the shellac from the transformer can heat up but cause no symptoms other than the smell. This is because the shellac breaks down over time. If it is a failing transformer then it must be replaced. The other major cause of this problem is the smell that comes from failing capacitors. An experienced technician can tell what the problem is by the smell.

And of course it can be repaired. As far as I know, power supplies from that time period do not contain any proprietary ic chips that cannot be found. They only contain components that are found in all other electronic products: transistors, diodes, capacitors, resistors, voltage regulators, and other components.

If you are concerned that there is a danger then simply disconnect the power supply from your computer and turn the power supply on. Then test the voltage from it and see if it is within spec. -12V, -5V, +12V, +5V.

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Joined: Oct 9 2011
Posts: 1063
Re: Funny smell Apple IIe power supply

Your right it could be a failing component. Never heard of the shellac thing unless there was a short and the transformer was overheating.

As for testing the supply. Remember it's a switching supply so it needs load. You will need a large power resistor to introduce load so you can measure the supply.

Cheers,
Corey

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Joined: Apr 11 2006
Posts: 1013
Re: Funny smell Apple IIe power supply

javster wrote:

...a sweet burning smell began to come out.

Welcome to the ranks of exploded line filter capacitors. Here's what you need to know.
http://www.mactalk.com.au/62/116421-apple-ii-power-supply-failed.html

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Joined: May 27 2013
Posts: 794
Re: Funny smell Apple IIe power supply

Corey986 wrote:

...Never heard of the shellac thing...

An Apple II expert told me this.

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Joined: Jan 19 2014
Posts: 59
Re: Funny smell Apple IIe power supply

It's definitely a failing line filter capacitor, as mentioned above. These capacitors smoke and stink like crazy when they eventually go, so you should definitely replace it before running your IIe for any longer. Sometimes you get lucky and the failing capacitor doesn't damage anything, but they can do some board damage if they "blow up in the wrong direction".

- Tom

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Joined: Jan 24 2005
Posts: 356
Re: Funny smell Apple IIe power supply

Speaking of funny smelling Apples...

Back in the day when I worked for an Apple dealer, this little old lady brings in her Apple II Plus for service. She complained that it got hot, and when it did, there was also an unusual odor that came from it's vicinity. She said she rarely uses it, that it's mostly for her grandson's use who is living in her house while attending college.

So, I took it back to the bench to look it over and quickly found the problem. Stuffed under the keyboard was a large ziplock baggie full of marijuana. I told the little old lady I could fix the problem for free and that it was an easy fix. I recommended she send her grandson back in to pick it up so I could show him how to prevent the problem in the future.

He comes in later that day kinda nervous and I just hand the machine back to him and told him he needs to find a different place to hide his stash. Relieved, he thanked me and left. Two years later, he had graduated and had started his own graphics art company (highly successful) and he bought all his Macs and laser printers from the store I had worked at to the tune of $60K.

MarkO's picture
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Joined: Dec 10 2011
Posts: 667
Re: Funny smell Apple IIe power supply

sfahey wrote:

Speaking of funny smelling Apples...

Back in the day when I worked for an Apple dealer, this little old lady brings in her Apple II Plus for service. She complained that it got hot, and when it did, there was also an unusual odor that came from it's vicinity. She said she rarely uses it, that it's mostly for her grandson's use who is living in her house while attending college.

<< SNIP >>

And Some People wonder why Apple Computers and Apple Users are so Cool......

MarkO