Re: UPS and inverter questions
The Rooskies have schematics, just Google your item.This is an example, I think it's the 500 Smart UPS....
cb92
Senior Member
Last Activity: 05-12-2016, 09:07 PM
Joined: 07-16-2008
Location: Atlanta, Ga.
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Re: Dell monitor
The chips are in, and that was the problem. I put a power supply in from E-bay, the one I fixed is a spare, good for testing 5v and 12v stuff. From this exercise I now have an optoisolator tester (see 'Instructables', "Altoid box optoisolator tester", a little power supply, and a lot of good experience.
Thanks one and all for the help. I now is an expurt.Leave a comment:
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Re: Anatek Peak DCA55 semiconductor analyser
I still have the ad I printed from AnaTek Corporation, [email]john@anatek.mv.com[/email] selling the ESR 60 for $179, the LC40 for $159 plus extra for the tweezers, clips, and carry case, and $159 for the DCA55, plus shipping. Too much.
It identified an LED for me, showed anode, cathode, specs. Very helpful.Re: Anatek Peak DCA55 semiconductor ... the tweezers,Leave a comment:
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Re: Reusing caps
I use a white marker to identify used parts. It's handy to mark polarity and to highlight items in photos.Leave a comment:
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Re: Dell monitor
Just something else to drive me crazy. Apparently optoisolators come in two sizes, normal and wider. The wider ones won't fit into a chip socket, so I'll modify one* for my tester, and have both sizes on the tester (*chip socket).
Meanwhile, all the optos I ordered from e-bay are probably the small size...luckily a standard one will just fit into the holes a wide one comes from. I sure hope I get a variety in case optos are made with different values. Still learning. Luckily, they are cheap, but it takes forever to get anything in the mail here. Aargh.Leave a comment:
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Re: Dell monitor
Thank goodness for E-bay. I'll get the parts to make my optoisolator tester, too. I've been collecting parts as I go.Leave a comment:
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Re: Dell monitor
D902 passed the out of circuit test.
I lifted the leg of r903 to pin 6, and it has about 80 vdc on it disconnected, 8mv connected. Seems like the chip is pulling the circuit down. I pulled the chip, and there is 10 ohms between 6 and 7. 15 ohms fro 7 to 5. 20 ohms from 7 to 3. 7 to 1,4,8 are open.
I'll see if Radio Shack has an ICE2A501. If this is a common chip, I'll get a couple while I'm there.Leave a comment:
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Re: Dell monitor
D902 checked out ok. But r902 has 38v in and 28 v out, and r903 has 28v in but only 8mv out....that goes to pin 6 on the chip, so...maybe that resistor is bad, even though it measures the correct resistance of 38k ohms?
connected to the board pin 6 to pin 7 is 11 ohms (the chip)Last edited by cb92; 01-07-2012, 09:04 PM.Leave a comment:
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Re: Dell monitor
I found that thread, too, makes for good reading. I think I searched the forums first, but did not use the correct term. Lots of good information, [B]I'll do all the tests, sooner or later I will find the culprit. [/B]
I would just love it if every time it was the same thing, but probably not to be.
I want to develop a check list for power supplies, so I can do a standard test on each one I encounter.Re: Dell monitor
I found that thread, too, makes for good reading. I think I searched the forums...Leave a comment:
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Anatek Peak DCA55 semiconductor analyser
Finally got my meter from E-bay for about sixty bucks delivered. Much better than the one hundred fifty or so they wanted originally. Sure am glad I got a deal, 'cause it can't recognize a voltage regulator, thinks it's a couple of LEDs. Hell, that's why I got it, those little regs look just like transistors!
It did recognize a darlington, npn, and pnp transistors, and a mosfet.
The really cute part is you can hook up a component any which way, and it will tell you which leg is which, a real help for me.
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Re: Dell monitor
I just put everything away, going to move it all to my workshop in town. The bench power supply did run the monitor, so it's only the power supply that is bad. I ordered one from e-bay for about 20 bucks delivered. I'll continue working on the old power supply for my education.
It really gets me that boards can be pristine and not work. I'm used to broken things looking broken. With practice, I'll be able to troubleshoot power supplies. I'm sure the more I work on them, the quicker I'll get to find the problem.Leave a comment:
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Re: Dell monitor
There is 8mv between pin 6&7 on the IC. Same across cap c907.
I try to post the optoisolator test.
I checked e-bay for replacement power supplies, there's plenty from $13 to $25 available. If I can get the monitor to work on a bench power supply, I'll order one. I see why my electronics salesman wondered why I bother to study this thing. I learn by doing and asking questions. Cheap items are not always available, I want to learn how to diagnose power supply problems. I'm concentrating on this one field, 'cause electronics is big-big-big....Leave a comment:
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Re: Dell monitor
The monitor is a Dell 1800FP. The Koreans sold this monitor to a lot of companies, from what I see. The 47uf cap #c907 is directly connected to the negative (-) leg of the rectifier. The solder track from it goes to the transformer and the (-) symbol on the board. Funny thing, the solder track has a gap right at the cap, but testing shows continuity through the track under it. I did a close up of that spot. there is a cap symbol right in the way of the solder track to the cap??? Seems funny to run solder that close, and then stop.
From the + symbol on the...Leave a comment:
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Re: Dell monitor
I got 165 volts DC across the cap,(same reading on either leg to the + on the rectifier) and the diode and resistor read ok on the board. The IC is ICE2a501. I removed the optoisolator and checked it, it didn't seem to test as 'ok'. I put on a used one, but no changes. I'm going to pick up some new optoisolators, ones I take off junk don't test as 'good'. Do they fail often? I'm looking for the most likely suspects in power supply repair.
And interesting side is that this monitor wants 5 volt and 12 volt. For a shop monitor, I'm considering finding...Leave a comment:
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Re: Dell monitor
Thanks a lot, Momaka. I think I see the cap you mention on the schematic. I got Paint.net, will see if it helps, changed the pic to jpeg, will re-post just to see if it's any better....Leave a comment:
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Dell monitor
This unit is ten years old, just for practice. I have ac and dc on the ac side of the smps. Nothing on the load side of the smps. There seems to be an optoisolator in the circuit. Is the smps bad or is it not getting turned on?
I hope the schematic comes through, I've been trying all day to downsize it.... -
Re: *****This section is NOT where to start threads asking questions*****
Hey, ratdude747, where is the thread to start threads asking questions? My Hadron Collider is making funny noises...
Oh, by the way, happy new year.Leave a comment:
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Re: UPS and inverter questions
Welcome, Aquaman and Seng, to the site most likely to help you repair your units. I've looked a lot elsewhere, this is the best.
Nontheless, UPS repair is a real tough one. I have gotten lucky a couple of times finding a loose connection on a battery, and a blown diode on another unit. Blown diodes are easy, they split down the middle! Everything else hides.....
There are some APC schematics available, but little else. The manufacturers don't want these units fixed, they want to sell new ones. As far as I'm concerned, anything below...Leave a comment:
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Re: SmartUPS 700 will not turn on
Concentrating on UPSes, I would like to know what is most likely to fail when the battery fails from age. This is the most likely fault to happen, you would think safeties would be built in, but maybe no, sell new ones.
I collect these victims. Upon visual examination I don't see any blown diodes, burnt traces, or any easy visual clues. The transformer is usually not burnt or too smelly (what's the rule, no smell, a little smell ok?).
Currently I'm looking at a Cyber Power 625 AVR, new battery, seemed to work, but came back from...Leave a comment:
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Re: substitute transistors
Yeah, kc8adu, I thought it was goofy. I asked the guy how long he had been in electronics, he said years, learned it in some school.
I only have these guys and Radio Shack here. As long as I know what I want, I have a chance. Some stuff is fairly priced, but some caps (2200 uf) or mosfets cost five bucks each. It's killing me. To get something in the mail is slow, slow, slow. UPS is a minimum of thirty bucks for one pound or less.
I end up breaking up stuff I find for components, that's why I need all the equivalent substitution info I can...Leave a comment:
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