How to fix my 5V, 2.5amp adapter.

[Jeff Liebermann]

On Sat, 21 Nov 2015 20:12:59 -0000, MJC <gravity@mjcoon.plus.com>
wrote:

In article <92c15btimbeeccg6j9pqjfs9lhdb7ee07b@4ax.com>,
jeffl@cruzio.com says...

It's actually quite easy. Instead of searching the web, I do an image
search. Photos, schematics, disassembly instructions, and such are
much easier to find using images than text.

Sorry, I still don't follow: what are you using as your search
criterion? I see how you might get disassembly instructions (or lots of
sales pitches!) using a photo of the outside of the device, but
schematics?

Mike.

Ok, I'll walk you through it. First, I do a web search by product
name and buzzword:
<https://www.google.com/#q=d+link+JTA0302+repair>
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:
<https://www.google.com/search?q=d+link+JTA0302+repair&tbm=isch>
(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.
<https://www.google.com/search?q=d+link+JTA0302+repair&biw=1397&bih=821&source=lnms&tbm=isch&sa=X&ved=0ahUKEwinr4_vy6LJAhUP8GMKHdV9COMQ_AUICSgE#tbm=isch&tbs=rimg%3ACZFH9IV11dHBIjg-oc7iGryprYGhMbJL3yU7s4yBEMwNeVqVguPgWuTPn2TyHae7nbkM1unm89X-59h8DZFv_1RHtmyoSCT6hzuIavKmtEVcoqqCFxshoKhIJgaExskvfJTsRfsuryv7U1zsqEgmzjIEQzA15WhH4nOkQgb56QyoSCZWC4-Ba5M-fET10TFIWWvIdKhIJZPIdp7uduQwR1e6tkiviKPIqEgnW6ebz1f7n2BETj_1Q1PRiNPCoSCXwNkW_19Ee2bEXI-6EAgeQ1c&q=d%20link%20JTA0302%20repair>
Here's one in Russian that looks interesting:
<http://masterpaiki.ru/goryachaya-shtuchka-d-link-ili-chinim-bp-jta0303e-e.html>
Use Google Translate to convert it to English.
<https://support.google.com/chrome/answer/173424?hl=en>

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

 

[Micky]

On Sat, 21 Nov 2015 14:43:57 -0800, Jeff Liebermann <jeffl@cruzio.com>
wrote:

On Sat, 21 Nov 2015 15:19:59 -0500, Micky <NONONOmisc07@bigfoot.com
wrote:

If I couldnt' find a power supply for the router, until I bought a new
one, could I have just unplugged the wire from the DSL modem to the
router and plugged it into the computer? The only thing I'm doing
wirelessly now is print, and I don't print very often.

Yes. 5V from the computer is the same as 5v from the Dlink wall wart.

No, no 5v at all. I mean eliminating the router and going straight
from the DSL modem to the network card in the computer. That's the
default, isn't it? It's only been 8 years but I can't remember.

That will work if:
1. If you're using PPPoE or PPPoA that require a login and password,
it will work if those are saved in the DSL modem or in the computah.
However, if you saved them in the router, you'll have to temporarily
move them.
2. If you trust your unspecified operating system to be secure
without the hardware firewall in the router. The DSL modem passes all
ports, even if it has internal DHCP, so your computah's firewall does
all the work.
3. If your DSL modem is independent of your router and doesn't
require a hack saw to seperate them.

Can't you find a 5V power source and a power jack and do it correctly?

I did already. It was just a question.

This is a repair newsgroup, not a substitution newsgroup. A 5v 2A
cell phone or tablet charger should work. Worst case is borrow the 5V
from the PC.

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

> Do something, even if it's wrong.

 

[Micky]

On Sat, 21 Nov 2015 17:04:20 -0500, "Ralph Mowery"
<rmowery28146@earthlink.net> wrote:

"Micky" <NONONOmisc07@bigfoot.com> wrote in message
news:che15bpl8f7hl7veoo3flifr2dp5dhj864@4ax.com...

If I couldnt' find a power supply for the router, until I bought a new
one, could I have just unplugged the wire from the DSL modem to the
router and plugged it into the computer? The only thing I'm doing
wirelessly now is print, and I don't print very often.

This idea kept popping in my head and then disappearing.

If you are talking about using the data cable and removing the router from
the system, you should be able to do it with out any problems. I do it from
time to time just to check the download and upload speeds.

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.
>

 

[Micky]

On Sat, 21 Nov 2015 14:18:35 -0800 (PST), John-Del <ohger1s@aol.com>
wrote:

It's a very common failure on supplies that run 24/7 to fail to restart after a cool down period.

Get any old hair dryer and give it a nice sauna for a few minutes, then plug it back in. If it starts, it's a high ESR cap in about 95% of the time.

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?

On Saturday, November 21, 2015 at 3:26:29 PM UTC-5, Micky wrote:
On Fri, 20 Nov 2015 09:50:15 -0800, mike <ham789@netzero.net> wrote:

On 11/20/2015 12:43 AM, Micky wrote:
How to fix my 5V, 2.5amp adapter.

I had 4 short power failures today, and everything on the PC started
up fine after the first 3. The fourth was longer so I went grocery
shopping.

When I restarted, none of the lights on the wireless router went on,
and an ohmmeter showed infinite resistance between the two prongs that
plug into the wall. I had a surge, didn't I?

Apparently it just cooled off!


P. S. This is what's broken:
http://www.ebay.com/itm/5V-2-5A-D-Link-JTA0302B-Power-Supply-Adapter/331703424856?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D20131003132420%26meid%3D9a7781190364427ebe948ecf4421bb96%26pid%3D100005%26rk%3D2%26rkt%3D6%26sd%3D301720248001
....

Bottom line...buy the new supply.

I did that. Should be here on Friday.

In the same way that planning for a vacation is almost as much fun as
the vacation, it seems yesterday planning to repair the PS was 1/3rd
the fun of actually doing it, plus I don't have a zener diode and even
the parts I do have become a little hard to find.

Problem with that one is the plug on the end is different from
most other router power supplies. Get the right one and be done with it.

They have the exact one, with the green plug showing in the photo.

I fix wall warts all the time for my own use. I'd never sell a gizmo
with a power supply that I repaired. Too much liability involved.

Most fail with shorted input diodes, but
that also blows the fuse.
I've been fixing stuff for almost half a century, but working on
line-connected
stuff still scares the hell out of me...and I've got a completely isolated
scope probe system.
Even if you do find out what's broke, where are you gonna get the
replacement part?
Putting it back together is problematic. What happens if you
try to unplug it and the glue breaks...you end up with AC in your
hands...not fun.

Look at the risk/reward ratio.
Best that can possibly happen is you save $7.50.
Worst is electrocution? burning down your house?
For stuff connected directly to the line,
if you don't know what you're doing, keep it that way.

If I did it, I'd do it right. I know what I'm doing. Not knowing which
part to replace doesn't mean I don't know what I'm doing.

 

[Phil Allison]

Ralph Mowery wrote:

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

 

[Ralph Mowery]

"Micky" <NONONOmisc07@bigfoot.com> wrote in message
news:rsu15bthseobsta8dkg05loaeu3299a6fs@4ax.com...

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.

 

[Micky]

On Sat, 21 Nov 2015 21:20:02 -0800 (PST), Phil Allison
<pallison49@gmail.com> wrote:

Ralph Mowery wrote:

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.

Thank you both.

... Phil

 

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.

 

[Tom Del Rosso]

Phil Allison wrote:

** 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.

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?

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

--