Curious Ea-72 Power Adapter Situation

[PaulBx1]

I got 3 (a mistake, should have been 2) EA-72 chargers from Conix with my new C1000. I then later noticed the posts here questioning them. I sent this comment to Conics:

I got 3 EA-72 power adapters, for 100 volts (I thought I was getting two, as your site implied). There have been reports that these will not tolerate the US 120 volts for extended periods, and that they may fail and possibly cause problems for the Zaurus. I am surprised you are shipping these marginal components as US-compatible. If I had known, I would have ordered the other (all voltage) adapter.

This is how he responded:

we had a customer test the EA-72 up to 160V,  for short periods  (at about 180v it will melt).

we haven't had any problems with the EA-72 in the USA, and have not had one returned with power problems from the USA since we started selling SL-C700.
(you may have received one extra by mistake, there is no need to return it)

Also in the early days we received a few SL-C700 back because of customer's bad adapters used in Europe, since we started supplying them with our tested adapters we haven't had one back from Europe either.

Guess I don't know what to think. Since I have a warranty on this, I will go with what the vendor says. One question occurs to me though. When people have had problems with EA-72s, what happens? Does the charger die, leaving the Zaurus untouched? Or does it kill the battery as it (the charger) is expiring? Or does it take the Zaurus along with it too?

One thing I don't understand at all is the concern I thought I read about the 1A current capability of the EA-72. I've been working in electronics since 1969, and I never heard of a case where a power source harmed anything by having too much current available. Too much voltage, yes; too little current, yes; but not too much current. It's not the job of the power source to limit current (which would require dropping the voltage if the current became "too much"). It's the job of the power sink.

Of course, I was not an analog electronics engineer, so what I just wrote might be completely wrong.  

[bluedevils]

I thought the problem with the 72s were that they are rated for 100V and when used with US 120V the output voltage is more than the required 5V or the output voltage no longer regulates.....

[sidmoraes]

I thought the problem with the 72s were that they are rated for 100V and when used with US 120V the output voltage is more than the required 5V or the output voltage no longer regulates.....
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No...
It is a regulated power supply.
I use two, and one of this is pluged in a 127V source, 24x7.

[uth]

I too just received my SL-C1000 with EA-72 adaptors.   Conics sells them as "North American", so I wasn't aware that these were the Japanese 100V ones until I received them.

What exactly is the issue with using them in North America?  I've been searching the threads and I can't find a definitive answer.  

The guy in this thread tested the EA-72 and says it puts out 5.13V  .44amps.  That's actually closer to spec than the often recommended EA-70s.
https://www.oesf.org/forums/index.php?showt...=13747&hl=ea-72

If that's true, then what is the problem?  Do they fry themselves after being exposed to 110-120V for a prolonged period?

If there is a reason to not use the EA-72, then what is a recommended, inexpensive altenative?   I want something I can pick up locally, so please don't say EA-70s.   I see some people say they use PSP adaptors.   Can any PSP adaptor be used?  Or are some better than others?   What about those universal adaptors with changable tips?

Obviously I want to start using my Zaurus asap, but I also don't want to do something to it I'll regret later, so I'd appreciate any advice.

[PaulBx1]

Well, I am using my EA-72's, and they work fine.

I find it hard to believe Conics would expose itself by using a power supply that cannot handle the voltage. The fact they bothered to test this in the past means they devoted some attention to it, and decided there was no issue. They are not flying in the dark.

I checked my output and it was 5.13 v. Even looked at it with a scope, it was nice and clean.

I have been trying to think up a cheap kludge to drop the AC input voltage down for it a few volts, a power resistor or something, just to give it more breathing room, but maybe I won't bother.

What this "problem" might be, is an internet phenomenon more than anything. On any given forum about some product, you hear a lot more from the people with problems than you hear from the happy customers. Combine that with electronics "infant failures" (some small percentage of electronics products fail early in their lifetimes) and we might just be seeing something that is a pseudo-problem, not a real one.

Maybe we need a poll here to find out what percentage of EA-72 users have run into issues.

[bluedevils]

I don't know about the new ones, but some of the older ipaq/hp adapters are the exact same spec.  I've used one with no known detriment.

[uth]

> What this "problem" might be, is an internet phenomenon more than anything. On any given forum
> about some product, you hear a lot more from the people with problems than you hear from the
> happy customers. Combine that with electronics "infant failures" (some small percentage of
> electronics products fail early in their lifetimes) and we might just be seeing something that is a
> pseudo-problem, not a real one.

I agree, I own other devices that work great for me, but if you go on certain sites where people can post reviews, you'll read many horror stories on those same devices.

I've been searching this forum for the posts about problems with the EA-72 charger, and they mostly seem to fall into the following categories:
- You can't use them in the US because 100V is printed on them (or a variation, Sharp shipped the EA-70s with their US models, therefore the EA-72 will explode if you use it in the US - or something like that)
- "I heard" they destroy Zauruses after awhile
- You need to use the EA-70s, which I just happen to sell in my internet store...

What seems to be lacking though is posts of the "The EA-72 destroyed my Zaurus and I can prove it" variety.

Now the EA-70s seems like a higher-quality unit in general, the EA-72 is slim and compact (and about 1/3 the price)  The decision to use the EA-70s vs a US version of the EA-72 could have simply been marketing rather than technical.

I'm not a power supply guru, but I know just enough to be dangerous     It seems to me that if the EA-72 puts out 5.13V in the US as you and other have measured,  and more current than the EA-70s (0.44 amps vs 0.38 amps), and it's regulated, then how can it possibly cause a problem?  It sounds like if anything, using the EA-70s should be riskier.   It seems like the biggest risk would be that the EA-72 would fry or melt from the higher US voltage.  According to Conics, it takes 180V to accomplish that.

But even after I rationalize it like that, I still have the fear of damaging my Zaurus with the EA-72s (Conics sent me three too).  But on the other hand, I really don't want to shell out another $30 for another power supply that's supposed to be safe.   I wish I hadn't fried my multimeter or I'd test them myself for piece of mind.  (as I said, just enough knowledge about power to be dangerous)

> Maybe we need a poll here to find out what percentage of EA-72 users have run into issues.

Not a bad idea.  I'd like to see a Wiki page on this topic also, maybe I'll go start one up.

[Mjolinor]

There seems to be a lot of concern about these things. As I have one and I live in the UK (230 volt) then I dismantled it for a look see.

It has a 1.6 amp 125 volt fuse on the live in and immediately after it there is a 230 volt transorb across the mains supply.

The main bridge for rectifying the mains has Z631 written on it. I can't find this anywhere to see what rating the diodes are, maybe someone else can.

The main smoothing cap after rectification is a 250 volt working electrolytic.

The primary - secondary opto isolator is a Sharp PC817 which has an isolation voltage of 5kV

So apart from the unknown bridge rectifier I see nothing in it that will prevent it working reliably at 120 volt. Maybe the working voltages are a bit close to the line but it wouldn't bother me. The PCB design bothers me a bit. The live - neutral clearances are very small but I think htat is probably because I am used to using 5mm for 230 volt.

[Antikx]

I don't know about the new ones, but some of the older ipaq/hp adapters are the exact same spec.  I've used one with no known detriment.
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I've been using an EA-72 and an IPAQ USB charger.  
I've been told that I live dangerously.  

[uth]

Well, there hasn't been as much response to the poll as I hoped, but everyone who responded said they didn't have issues using the EA-72.

Anyway, if it has a fuse on the input side, and puts out a regulated voltage that's within the range of the 'safe' adaptors.  Then how can it possibly be a problem?   Maybe people had problems with faulty EA-72s or faulty Zauri to begin with?

Anyway, thanks to everyone who responded to this thread, and my poll, I fell much safer using the EA-72 now.

[PaulBx1]

There was a poll somewhere?    I guess I don't know my way around this forum very well. Anyway I would vote that the EA-72 is OK also.

[Antikx]

Phewww... found the poll: EA-72 Poll

[cmonex]

sheesh. i have the original EA-72S. i live in europe and couldn't find a 230V-100V voltage converter so using a 230V-110V.  
now you got me worried  

[uth]

sheesh. i have the original EA-72S. i live in europe and couldn't find a 230V-100V voltage converter so using a 230V-110V.  
now you got me worried  
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Sorry  .    Actually this thread has helped put my mind at ease.    Some other threads have dire warnings about the EA-72 based on nothing but anecdotes.   From a technical standpoint, it should have no problem with 110V.  In the poll I put up, there has not been one person who's reported damage.  So the weight of the evidence suggests that they are safe at 110V  

[cmonex]

Sorry  .    Actually this thread has helped put my mind at ease.    Some other threads have dire warnings about the EA-72 based on nothing but anecdotes.   From a technical standpoint, it should have no problem with 110V.  In the poll I put up, there has not been one person who's reported damage.  So the weight of the evidence suggests that they are safe at 110V 
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well no problem ..  not your fault  i mean this thread is the first i found about this issue (or non issue lol)
technically & theoretically 110V shouldn't be a problem but i don't know the zaurus so well, so far...
btw! i've been using a sigmarion 3 for more than half a year now, this is also a japanese machine with a 100V ac adapter. been using it on the 110V converter and no problems so far though i'm afraid the sig3 isn't perfectly happy (i saw a few strange stuff..)
would that count too in your poll?