Apple iigs power supply question #3

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I am in trouble.

Can anyone help me?

I am replacing the capacitors in this Apple iigs power supply:

Astec model AA13581 Apple part number 699-0126.

Some of the capacitors in this power supply are extremely hard to remove because there is a ton of glue on top and around them.

In removing one of them, I stretched the wires a little bit in component L7.

I don't know what this thing is because I cannot identify the symbol under it.

I don't know how to test it.

I don't know if this thing has a polarity.

Because of that I don't know how to put it back in.

I am afraid that if this thing is polarized and I install it incorrectly, I might mess up the power supply.

I will attach an image of the symbol of this component so that maybe one of you can identify it.

EDIT:

Okay, in removing this component from my other power supply, I found the same symbol inside a different component that I know for certain is an inductor.

What I don't know is why Apple used this symbol to designate an inductor?

Is it a special inductor or some arbitrary choice on the part of Apple?

AttachmentSize
symbol.JPG6.29 KB

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Joined: Dec 13 2013
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Re: Apple iigs power supply question #3

It sounds like you disturbed one of the chokes that are up against the filter caps. They are not polarity sensitive and you should be able to push it back into shape. Once you confirm that the supply is working, you can take a hot glue gun and re-apply the glue around the components. Make sure you replace the X and Y type safety capacitors as they are probably bad by now as well. They are the rectangular caps near the AC input side of the board. Also the supply needs a load to operate correctly, I use an old hard drive connected up to the +5, +12, and common.

Good Luck,

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Dick Stachowiak
East Syracuse, NY

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Re: Apple iigs power supply question #3

There is only one rectangular capacitor near the ac side of this power supply.

And I have no idea how to find a replacement.

I don't know about the ratings or anything.

There are numbers and letters galore on this particular rectangular capacitor.

And from what I remember, these fail often but do not pose any risk when they do.

Am I wrong...?

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Re: Apple iigs power supply question #3

Sorry, repeat post due to slow connection.

speedyG's picture
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Re: Apple iigs power supply question #3

Hello insanitor,
did you checkout this page and it´s following pages :
http://www.appleii-box.de/D04_allabotpowersupplies.htm
?
speedyG

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the second part includes less friends but a lot more joy on life....

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Re: Apple iigs power supply question #3

speedyG wrote:

Hello insanitor,
did you checkout this page and it´s following pages :
http://www.appleii-box.de/appleboxallabotpowersupplies.htm
?
speedyG

Yes, I looked through them all.

But I can't make sense of it.

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Re: Apple iigs power supply question #3

Some of the safety caps were filled with some sort of oil. When they fail they spray a stinking burning goo all over the supply. The ones that have a dark gold color are almost always bad. If you post a picture of the text that's on the cap, I can decipher it and give you a source. I automatically replace them on every supply I rebuild. By the way, if you ever have to clean up after one fails, nothing works better than Windex window cleaner.

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Dick Stachowiak
East Syracuse, NY

speedyG's picture
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Re: Apple iigs power supply question #3

That oily stuff is boracic acid, a really ugly stuff.....

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the second part includes less friends but a lot more joy on life....

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Re: Apple iigs power supply question #3

stachowiak wrote:

Some of the safety caps were filled with some sort of oil. When they fail they spray a stinking burning goo all over the supply. The ones that have a dark gold color are almost always bad. If you post a picture of the text that's on the cap, I can decipher it and give you a source. I automatically replace them on every supply I rebuild. By the way, if you ever have to clean up after one fails, nothing works better than Windex window cleaner.

It is impossible to take a picture of such tiny lettering with the cameras I have.

It is also very difficult to see these things unless you have a magnifying glass or a 10x loupe like the one that I used.

I have drawn by hand all the logos, numbers, symbols and letters by hand and scanned it into readable large files.

I have put the scans into a zip file up on my website because I don't know how to post pictures here unless I start another thread.

And I don't want to go crazy every time I need to post pictures that other people request in threads already made.

Remember, as I said... There is only one rectangular capacitor on this power supply. Not two.

Here is the link to the file:

http://www.insanecrazy.com/ps.zip

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Re: Apple iigs power supply question #3

Okay, stachowiak.

I have tried very hard to come up with the correct replacement and I have narrowed it down to four candidates:

http://www.digikey.com/product-search/en?pv5=10139&FV=fff40002%2Cfff80010%2C400002%2C1140050%2C14300019&k=.01uf+250v+y+capacitor&mnonly=0&newproducts=0&ColumnSort=0&page=1&quantity=0&ptm=0&fid=0&pageSize=25

Out of these four, my absolute best guess is this one:

http://www.digikey.com/product-detail/en/PME271Y510MR30/399-5412-ND/1927357

What do you think?

P.S. And I still can't find any other rectangular capacitor in this power supply.

Does that mean that there is no X capacitor in this power supply?

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Re: Apple iigs power supply question #3

As long as the Lead spacing will fit the holes in the board, your best guess should be fine. The Y type caps are primarily for the reduction of interference and when they fail, they go open. You must have at least one X type cap in your supply. Some of the later supplies had a cap that was rectangular but had rounded corners. It should be very close to the end of the board where the AC enters. I just sent out a batch of repaired IIGS supplies, so I'm sorry that I can't be more specific as I don't have anything here to refer to.

Good Luck,

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Dick Stachowiak
East Syracuse, NY

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Re: Apple iigs power supply question #3

stachowiak wrote:

As long as the Lead spacing will fit the holes in the board, your best guess should be fine. The Y type caps are primarily for the reduction of interference and when they fail, they go open. You must have at least one X type cap in your supply. Some of the later supplies had a cap that was rectangular but had rounded corners. It should be very close to the end of the board where the AC enters. I just sent out a batch of repaired IIGS supplies, so I'm sorry that I can't be more specific as I don't have anything here to refer to.

Good Luck,

It seems that luck won't help me much, I'm afraid.

The ONLY capacitors in the areas that you specified that even REMOTELY resemble what you are describing do not (according to the datasheets I found) perform any safety function whatsoever.

On the first power supply there are many of these capacitors everywhere (they are a dark brown slightly red color) which have numbers on them that say things like "224k 250v or 103k 630v".

The second power supply has a lot of these also but one of them is different.

It is blue, and it says, "2E224" on it (whereas on the first power supply in this exact location has a capacitor that says, "224K 250v").

If this "2E224" capacitor is not the correct one then I simply do not know where it is.

I hope to get a confirmation on the correct one by Monday. Otherwise, I'll have to rely on the salesman at the electronics store on Monday and who knows if he can find this thing or if he will be honest enough to sell me the correct one instead of selling me a bunch of the wrong ones.

I am so sorry, but this is very frustrating. It feels like I am looking for some miniature obscure street on a large map where everybody tells me that "You must see it, it's right there! Don't you see it? It must be there!" and I look at that location 10000000 times and find absolutely nothing.

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Re: Apple iigs power supply question #3

I think that the 2E224 and the 224K 250v cap has to be your X2 cap. I went back to see what I purchased in the past and it was a .22uf 275V X2 cap. I got them on ebay in bulk in the past, here's a link to the auction http://r.ebay.com/V8ypzr it's more than you need but cheep and free shipping. If you have an ohm meter you could see if you have continuity from each side of the AC input to each side of the cap. Make sure that the power switch is in the on position and that you don't have the power cord plugged in. That will confirm you are on the right cap.

I'm confident that you will get thru this,

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Dick Stachowiak
East Syracuse, NY

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Re: Apple iigs power supply question #3

I have just finished doing some continuity testing as you have suggested. The two terminals of the 2E224 cap are connected to the two terminals of the AC input.

I can put this another way. If (hypothetically) the power supply ran on DC power instead of AC power, then the positive input is connected to one terminal of this cap, while the other terminal of this cap is connected to the negative input.

I am not sure what this means exactly, but it could be that this cap is the x cap we're looking for, or the cap is supposed to smooth out the AC input as it goes into the rest of the power supply. Which would mean that this cap performs another purpose.

What do you think?

P.S. can you explain to me why .22uf is equivalent to 224k?

And do these safety caps have a polarity? I don't want to install them incorrectly.

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Re: Apple iigs power supply question #3

You have definitely found the X2 cap. They are non polarized caps so you don't have to worry about how you install it. Some caps might have a stripe on one end, but that only indicates what lead is connected to the outermost foil layer. In some audio circuits the caps are installed with the foil side connected whatever way the hum pickup is less. The cap doesn't do any smoothing to the 60hz AC input, it only shunts the high frequency hash that the switching supply generates. The 224 is just another way to represent the value that is a common way for manufacturers to mark components. Here's a link that has a chart http://www.elecraft.com/Apps/caps.htm

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Dick Stachowiak
East Syracuse, NY

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Re: Apple iigs power supply question #3

Oh, I did not know that another type of cap other than those small circular disc brown caps used the same coding scheme.

I will be going to the electronics place tomorrow to buy quite a few caps.

I have another Power Supply here (same model) that has a 330uf bulging cap, and a cracked Y cap.

I also have three Power Supplies here of the other model (dynacomp) which one of them is giving out the wrong voltages, and the other two are dead. I plan to replace two caps in each (1uf) to see if that does the trick.

P.S.

About the X safety capacitor. Based on another thread here, I have looked around for a place that sells an x capacitor that would work.

Check this link and tell me if this will work or not: (just looking for more than one option. I'll probably get the ones on ebay if the local place has none in stock)

http://www.mouser.com/ProductDetail/Cornell-Dubilier-CDE/158X224K/?qs=sGAEpiMZZMv1cc3ydrPrF0wSKh9ZwLhG0MoWMuAjeZk%3d

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Re: Apple iigs power supply question #3

The spec on the Mouser cap looks fine. You might consider getting one of these http://r.ebay.com/SVSSLL for testing caps. It's low price and they work well for measuring ESR. It's not lab grade but will help you find bad caps that you won't find with a multimeter. Having caps with low ESR is a must with switching supplies. As far as the dead power supplies, they are usually the easiest to fix. Typically they will have an open 100KΩ resistor or open small electrolytic cap on the board between the AC input and the transformer that prevents them from starting up. You can do a quick test of most of the resistors while they are in circuit. If they read higher in resistance than they should, they are probably bad. If they read lower, most likely you are reading other components that are in parallel with it, and you will need to remove at least one lead off the board to get a good reading. Remember that you need to have a load on the supply before you test the supply for the correct voltages. I don't recommend using the logic for a load. If the 5 volt output is running wild you could fry a perfectly good board. I also test the supplies with a load resistor and amp meter on the +5 and +12 outputs to confirm that the supply can deliver the specified voltage and current without making any strange hissing or chirping sounds.

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Dick Stachowiak
East Syracuse, NY

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Re: Apple iigs power supply question #3

I will tell you about my trip and diagnostics tomorrow.

In the meantime I will follow this lead:

http://www.ebay.com/itm/321486425943

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Re: Apple iigs power supply question #3

The local electronics place had absolutely no safety caps.

I had to order through the mail.

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Re: Apple iigs power supply question #3

I have a pretty good electronic supply house in Syracuse NY and was surprised that they also had nothing in the way of X or Y safety caps. I do a lot of electronic repair as well as a lot of antique radio repair. Much of the vintage stuff used regular paper and foil caps that when they fail, put the line voltage directly to the chassis. Most technicians replace them with the same unrated crap that originally failed, and many have no knowledge of safety rated caps or why they're important to use.

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Dick Stachowiak
East Syracuse, NY

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Re: Apple iigs power supply question #3

What you are saying makes perfect sense to me.

I usually find that while some people have capabilities, the standards for which they should be used is often lacking.

I was a watchmaker by trade and I have seen a lot of really crazy things done to some of the watches I repaired.

It's amazing what some people would go through to try to fix something.

However, I understand the problem.

Information is not always available.

I will report back to this thread once I get the caps and after I do some testing.

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Re: Apple iigs power supply question #3

I have not conducted any testing yet except whether the PSU will turn on or not.

The x safety caps on Ebay were probably for the Dynacomp power supply because they are big.

Too big in fact for the Astec power supply.

However, I was able to drill some holes through the circuit board and install the x cap that way.

I will conduct a voltage test under load and after I keep the computer on for a while.

I will report back with the results.

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Re: Apple iigs power supply question #3

Here are the results of my testing.

I ran the Apple iigs for 12 hours.

When the 12 hours were over, I took voltage measurements under load:

Red wire: +5.00v <-- The disk drives booting did not change this reading.

Yellow wire: +11.75v +11.56v with the disk drives booting.

Green wire: -11.56v 11.64v with the disk drives booting.

Blue wire: -5.16v -5.18v with the disk drives booting.

Thanks guys for all your help. This PSU seems to be in perfect working order now.