How to fix my 5V, 2.5amp adapter.

Nov 20, 2015 28 Replies

Ok, I'll walk you through it. First, I do a web search by product name and buzzword: The first hit is the page I posted, which is more luck than finesse. However, we're looking for a schematic, so I click on the "Images" button for: (Edited and shortened for clarity). Notice that several schematics magically appear in the results.

Let's pretend that you don't see the schematic that you're looking for. Click on ANY schematic. The search results will display the image with "Visit Page" and "View Image" button. However, we're gonna do something different. In the lower right are a series of thumbnails one of which is labeled "View More". Click that and you have pages and pages of similar schematics to sift through. Here's one in Russian that looks interesting: Use Google Translate to convert it to English.

In case you haven't noticed, it really doesn't matter exactly what you use for a search. At a minimum, the model number. Notice that I chopped off the version suffix letter from the model number. Instead of "repair", you could use inside, schematic, disassemble, tear apart, bulging capacitor, etc. Whatever works to bring up images that are close. Your eyes do the rest.

Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558

I did already. It was just a question.

You mean USB, or something on the mobo? I'd have to fix up a cable to do that.

Good. It looks like "wire" was too vague a term. Two people thought I meant the power wire (because that's what we'd been talking about) and even you asked if really meant the data cable. Sorry.

>

Aha. I saved a hair dryer I got somewhere just for testing electronics, but I had in mind testing for things that do NOT work when they're hot. I'll remember to test for those that work when they ARE hot. I could test this very PSU...oh, that's what you meant. (I thought you were giving general advice.)

I'll dig out the hair dryer and do that.

In ESR cap, what does ESR mean?

Look up equivilent series resistance. In short it is a number that tells of the quality of the capacitor especially when used in switching and high frequency circuits.

Most any old capacitor will be ok for filtering out 60 hz in the old power supplies. When the switchers came out , the capacitors begain to fail . Checking on a simple capacitor meter will show the value ok, but they fail under the high speed/frequency high current usage.

** The ESR of an electro cap is mostly due to the conductivity of the liquid electrolyte used inside.

Modern, water based electrolytes have much better conductivity and hence lower ESR values compared to the same size caps made in the past and so can handle higher operating currents without excessive self heating.

Heat is the main killer of electros, whether from the local ambient temp or current flow in the cap or both. Luckily, the conductance of electrolytes improves with increasing temp which helps extend their life in SMPS.

... Phil

Thank you both.

If you have a dead open at the AC input, It could also be an open srge current limiter, thats the device in series w the fuse. It's supposed to be a high resistance when cold and change gradually to a low resistance As it heats.

What time frame do you mean by "modern" as opposed to "past?"

When motherboard caps fail long after the "plague" was over, is it mainly due to the voltage being under-rated?

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