Wireless Networking wrt54 v1, too much voltage

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Subject Author Date
wrt54 v1, too much voltage suckithard 05-23-08
Posted by on May 23, 2008, 3:04 pm
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I've got a linksys wrt54g v1.0 that I've burned by using the wrong ac
adapter. I accidentally used a 10v dc adapter. It ran for ~10 minutes
before I heard multiple pops, and a smell of burning chips. Now, if I
plug in the original adapter nothing happens, the leds don't come on.
Cosmetically I don't see anything wrong with the board or components.

I've read the thread on the fried wrt54g because of ac. But I didn't
see a solution. From that thread, it seems that the buck converter
chip, and the diodes are probably the culprits. Is there anyway to
test them? or are there other components that seem likely too?

Posted by Jeff Liebermann on May 23, 2008, 7:09 pm
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On Fri, 23 May 2008 12:04:52 -0700 (PDT), suckithard@gmail.com wrote:

>I've got a linksys wrt54g v1.0 that I've burned by using the wrong ac
>adapter. I accidentally used a 10v dc adapter.

Poof. The v1.0 mutation runs on 5V 2A adapter.

>It ran for ~10 minutes
>before I heard multiple pops, and a smell of burning chips. Now, if I
>plug in the original adapter nothing happens, the leds don't come on.
>Cosmetically I don't see anything wrong with the board or components.
>
>I've read the thread on the fried wrt54g because of ac. But I didn't
>see a solution.

No solution. I can identify the components that are fried, which can
be replaced if you like.

>From that thread, it seems that the buck converter
>chip, and the diodes are probably the culprits. Is there anyway to
>test them? or are there other components that seem likely too?

It's easier and cheaper to replace them.
Duz your v1 look like the v1 in the photo?
<http://www.linksysinfo.org/images/Content/Autopsy/WRT54G-mblg.jpg>
If ues, then it's an RT9202 regulator with external FET's to increase
the power output.
<http://www.richtek.com/www/Docs/DS9202-08.pdf>
I'm not sure about the numbers on the FET's

Or does it look like this?
<http://802.11junk.com/jeffl/pics/wireless/WRT54G/slides/wrt54g-v1.1.html>
If yes, it's an AP1501-33:
<http://www.diodes.com/datasheets/AP1501.pdf>

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

Posted by Kim Clay on May 23, 2008, 7:45 pm
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On Fri, 23 May 2008 12:04:52 -0700 (PDT), suckithard@gmail.com wrote:

>I've got a linksys wrt54g v1.0 that I've burned by using the wrong ac
>adapter. I accidentally used a 10v dc adapter. It ran for ~10 minutes
>before I heard multiple pops, and a smell of burning chips. Now, if I
>plug in the original adapter nothing happens, the leds don't come on.
>Cosmetically I don't see anything wrong with the board or components.
>

If the 10V adapter was a linear device (transformer inside) then its
output voltage may have been 12-15V easily. Or more!

>I've read the thread on the fried wrt54g because of ac.
Good job doing a search first!!

>But I didn't see a solution.
Replace
Find a used v2, v3, or v4 or a newer GL version.
Or a Buffalo WHR-HP-G54 if you can find one.

> From that thread, it seems that the buck converter
>chip, and the diodes are probably the culprits.
Yes - the smps & the TL7705 supervisory chip is all I could find that
ran directly from the +5V input.

>Is there anyway to test them?
Not easily.
Repair is probably possible but not worth the hassles!!

>or are there other components that seem likely too?
TL7705 - it might have survived - see above.

It could have been worse I suppose - the v1.0 only had a 125MHz cpu.
I think all other versions have at least a 200MHz.

Having said that, my v1.0 has been running dd-wrt nicely in an outdoor
enclosure for 9 months now.

kc


Posted by on May 23, 2008, 10:41 pm
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>Duz your v1 look like the v1 in the photo?
><http://www.linksysinfo.org/images/Content/Autopsy/WRT54G-mblg.jpg>
>If ues, then it's an RT9202 regulator with external FET's to increase
>the power output.

It's definitely a 1.0, with the minipci card.
I found that the RT9202 isn't produced anymore, but I also found an
identical replacement.
I plan on ordering it, and the diodes from mouser.com. But the diodes
are a bit of a problem. I have no idea what specification they are.
All I know is that they are surface mounted. Do you guys know their
specs? or do diodes even have specs? I've only worked with the typical
generic ones from mechatronics labs, and I've never blown any of
those.

Also, are the FETs possible culprits too? Are they sensitive to higher
voltages?

>Not easily.
>Repair is probably possible but not worth the hassles!!

With the prices I've seen on ebay, repair may be the cheapest for me.
and I've got to break that new soldering iron in sometime. :)
I've been running newer versions of the wrt54g but they don't seem as
stable as the original.

Posted by Jeff Liebermann on May 23, 2008, 11:05 pm
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On Fri, 23 May 2008 19:41:23 -0700 (PDT), suckithard@gmail.com wrote:

>>Duz your v1 look like the v1 in the photo?
>><http://www.linksysinfo.org/images/Content/Autopsy/WRT54G-mblg.jpg>
>>If ues, then it's an RT9202 regulator with external FET's to increase
>>the power output.
>
>It's definitely a 1.0, with the minipci card.
>I found that the RT9202 isn't produced anymore, but I also found an
>identical replacement.

Where? I'm interested.

>I plan on ordering it, and the diodes from mouser.com. But the diodes
>are a bit of a problem. I have no idea what specification they are.

Look on the schematics on the data sheet:
<http://www.richtek.com/www/Docs/DS9202-08.pdf>
Panasonic makes the MA732 diode on the schematic. Looks like a fast
shottky diode.
<http://www.datasheetcatalog.com/datasheets_pdf/M/A/7/3/MA732.shtml>

>All I know is that they are surface mounted. Do you guys know their
>specs? or do diodes even have specs? I've only worked with the typical
>generic ones from mechatronics labs, and I've never blown any of
>those.

Yes, diodes have specs. There are quite a few different types.

>Also, are the FETs possible culprits too? Are they sensitive to higher
>voltages?

It's highly likely that both FET's are also blown. I had numbers off
of those from the board, but I don't have V1 board handy.

>With the prices I've seen on ebay, repair may be the cheapest for me.

Ok. However, I value my time. What I do is buy the parts, stick them
to the unit, and wait until I have some of that mythical spare time to
work on it. Then, I do perhaps a dozen repair jobs at once. Setup
and cleanup time plus finding the parts is what kills me, not the
parts cost.

>and I've got to break that new soldering iron in sometime. :)
>I've been running newer versions of the wrt54g but they don't seem as
>stable as the original.

Duz the new version have a version number? I'm running v24 RC6.2 on
perhaps a dozen local wireless hot spots and business customers, with
zero issues. I haven't tried RC7 yet.

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

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