Sharp Aquos LC20E1-S LCD TV Strange AC adapter

M

Michael Kennedy

Guest
Hi everyone..

I recently got a Sharp Aquos LC20E1-S LCD TV. The problem is it didn't come
with a power brick.

The unit runs on 13VDC and uses 54W.. I managed to find a picture of the
power brick for this TV and it has 3 seperate 13V connections to the board
inside. I have checked the board with an ohm meter and they are completely
seperated inside. One power wire goes to the audio amp, one to the tuner /
lcd control board and one to the backlight inverter. I'm not really sure for
the reason of seperating them, but I assume that it is for interference
reasons and that the TV should power up if given 13V to all of those points
even if from the same source.

Anyhow I have tried powering it by tying all of the 13V+ togeather and
giving them 13V and I get nothing except for a small noise from the speakers
and a light very briefly turns on. Just enough to see it.

Does anyone have any expirenence with this TV? I have a friend with the same
tv.. Maybe I can borrow their AC adapter and try it on this one.

Here is a pic of the same TV and the strange DC jack.

"http://f11batchimg.auctions.yahoo.co.jp/users/1/7/7/3/reuse_store-imgbatch_1253519810/400x600-2009092100127.jpg"

"http://tinyurl.com/knpq4t"


Power brick
"http://img193.auctions.yahoo.co.jp/users/4/3/3/2/smdtk695-img600x450-1253178530nulnxz50227.jpg"

"http://tinyurl.com/m8wrv7"

Thanks..

Mike
 
Michael Kennedy <mike@nospam.com> wrote in message
news:bs-dnbqdUbGO1yrXnZ2dnVY3goudnZ2d@giganews.com...
Hi everyone..

I recently got a Sharp Aquos LC20E1-S LCD TV. The problem is it didn't
come
with a power brick.

The unit runs on 13VDC and uses 54W.. I managed to find a picture of the
power brick for this TV and it has 3 seperate 13V connections to the board
inside. I have checked the board with an ohm meter and they are completely
seperated inside. One power wire goes to the audio amp, one to the tuner /
lcd control board and one to the backlight inverter. I'm not really sure
for
the reason of seperating them, but I assume that it is for interference
reasons and that the TV should power up if given 13V to all of those
points
even if from the same source.

Anyhow I have tried powering it by tying all of the 13V+ togeather and
giving them 13V and I get nothing except for a small noise from the
speakers
and a light very briefly turns on. Just enough to see it.

Does anyone have any expirenence with this TV? I have a friend with the
same
tv.. Maybe I can borrow their AC adapter and try it on this one.

Here is a pic of the same TV and the strange DC jack.


"http://f11batchimg.auctions.yahoo.co.jp/users/1/7/7/3/reuse_store-imgbatch_
Click to expand...
1253519810/400x600-2009092100127.jpg"
"http://tinyurl.com/knpq4t"


Power brick

"http://img193.auctions.yahoo.co.jp/users/4/3/3/2/smdtk695-img600x450-125317
Click to expand...
8530nulnxz50227.jpg"
"http://tinyurl.com/m8wrv7"

Thanks..

Mike
Click to expand...

So there maybe one or more floating voltages, you'll need perhaps 3 separate
supplies and moulding up/exchanging for, your own connector

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/
 
<Snip>

Here is a pic of the same TV and the strange DC jack.


"http://f11batchimg.auctions.yahoo.co.jp/users/1/7/7/3/reuse_store-imgbatch_
1253519810/400x600-2009092100127.jpg"

"http://tinyurl.com/knpq4t"


Power brick

"http://img193.auctions.yahoo.co.jp/users/4/3/3/2/smdtk695-img600x450-125317
8530nulnxz50227.jpg"

"http://tinyurl.com/m8wrv7"

Thanks..

Mike
Click to expand...

So there maybe one or more floating voltages, you'll need perhaps 3
separate
supplies and moulding up/exchanging for, your own connector
Click to expand...

Well for testing I just soldered all of the positive contacts togeather to
one wire and the same for the neg and then soldered those to a barrel
connector jack.

It didn't let out any magic smoke when doing this so I guess it is okay
still, although I'm unsure if it was working beforehand because I have no
power supply.

Mike
 
There are several reasons why Sharp chose to use three separate supplies.
One was to minimize the cost of a building a single "rilllly big" supply.
The other is that it wanted to minimize the amount of bypassing and
decoupling needed on the boards.

The obvious answer to the question of why the set didn't work is that it
doesn't "like" being driven from a single supply. (The original supply was
likely missing because the was tossed out as defective (for whatever unknown
reason)).

I would not have plugged a single supply into it, simply on the (admittedly
remote) possibility that it might be damaged.
 
On Mon, 21 Sep 2009 20:44:13 +0900, "Michael Kennedy"
<mike@nospam.com>wrote:

Snip

Here is a pic of the same TV and the strange DC jack.


"http://f11batchimg.auctions.yahoo.co.jp/users/1/7/7/3/reuse_store-imgbatch_
1253519810/400x600-2009092100127.jpg"

"http://tinyurl.com/knpq4t"


Power brick

"http://img193.auctions.yahoo.co.jp/users/4/3/3/2/smdtk695-img600x450-125317
8530nulnxz50227.jpg"

"http://tinyurl.com/m8wrv7"

Thanks..

Mike







So there maybe one or more floating voltages, you'll need perhaps 3
separate
supplies and moulding up/exchanging for, your own connector


Well for testing I just soldered all of the positive contacts togeather to
one wire and the same for the neg and then soldered those to a barrel
connector jack.

It didn't let out any magic smoke when doing this so I guess it is okay
still, although I'm unsure if it was working beforehand because I have no
power supply.

Mike
Click to expand...
Cha Ching! You 'don't' know if it was working prior to your purchase.
My guess is it was not and that reason could be why the supply wasn't
provided to you.
 
"William Sommerwerck" <grizzledgeezer@comcast.net> wrote in message
news:h97pi6$vqk$1@news.eternal-september.org...
There are several reasons why Sharp chose to use three separate supplies.
One was to minimize the cost of a building a single "rilllly big" supply.
The other is that it wanted to minimize the amount of bypassing and
decoupling needed on the boards.

The obvious answer to the question of why the set didn't work is that it
doesn't "like" being driven from a single supply. (The original supply was
likely missing because the was tossed out as defective (for whatever
unknown
reason)).

I would not have plugged a single supply into it, simply on the
(admittedly
remote) possibility that it might be damaged.
Click to expand...
Well if I were back home where I have a workbench and loads of wire and
power supplies laying around I would have wired it up as it was intended.
But unfortunately where I'm at now I don't many tools or parts to work with.
Upon first looking at I thought they made seperate supplies just to save
money on the design of the PSU and or for RFI protection.
 
Michael Kennedy wrote:
I recently got a Sharp Aquos LC20E1-S LCD TV. The problem is it didn't come
with a power brick.

The unit runs on 13VDC and uses 54W.. I managed to find a picture of the
power brick for this TV and it has 3 seperate 13V connections to the board
inside. I have checked the board with an ohm meter and they are completely
seperated inside. One power wire goes to the audio amp, one to the tuner /
lcd control board and one to the backlight inverter. I'm not really sure for
the reason of seperating them, but I assume that it is for interference
reasons and that the TV should power up if given 13V to all of those points
even if from the same source.
Click to expand...
I rescued a similar set. The three supplies are, in fact,
separate (common return). I didn't bother to sort out "why"
as the set I have came with the brick. But, the schematic shows
them as separate.

Some possible reasons:
- keep the backlight supply isolated from the signal processing
supply (keeps audio/video cleaner)
- make sure the "processor" power supply comes up before other
supplies
- allow the processor to run even if the other supply(ies) die
(so it can blink an error indicator)
- etc.

Anyhow I have tried powering it by tying all of the 13V+ togeather and
giving them 13V and I get nothing except for a small noise from the speakers
and a light very briefly turns on. Just enough to see it.
Click to expand...
I'm not sure I would have arbitrarily tied all of the supplies together.
There might be some power sequencing issues that your "patch" could
make problematic. Of course, its too late *now*... :>

Does anyone have any expirenence with this TV? I have a friend with the same
tv.. Maybe I can borrow their AC adapter and try it on this one.
Click to expand...
That's the *first* thing I would have tried (realizing that you
*could* possibly toast their brick in the process -- so hope it
is an understanding friend! :> )
 
"D Yuniskis" <not.going.to.be@seen.com> wrote in message
news:h991cg$ob1$1@aioe.org...
Michael Kennedy wrote:
I recently got a Sharp Aquos LC20E1-S LCD TV. The problem is it didn't
come with a power brick.

The unit runs on 13VDC and uses 54W.. I managed to find a picture of the
power brick for this TV and it has 3 seperate 13V connections to the
board inside. I have checked the board with an ohm meter and they are
completely seperated inside. One power wire goes to the audio amp, one to
the tuner / lcd control board and one to the backlight inverter. I'm not
really sure for the reason of seperating them, but I assume that it is
for interference reasons and that the TV should power up if given 13V to
all of those points even if from the same source.

I rescued a similar set. The three supplies are, in fact,
separate (common return). I didn't bother to sort out "why"
as the set I have came with the brick. But, the schematic shows
them as separate.

Some possible reasons:
- keep the backlight supply isolated from the signal processing
supply (keeps audio/video cleaner)
- make sure the "processor" power supply comes up before other
supplies
- allow the processor to run even if the other supply(ies) die
(so it can blink an error indicator)
- etc.

Anyhow I have tried powering it by tying all of the 13V+ togeather and
giving them 13V and I get nothing except for a small noise from the
speakers and a light very briefly turns on. Just enough to see it.

I'm not sure I would have arbitrarily tied all of the supplies together.
There might be some power sequencing issues that your "patch" could
make problematic. Of course, its too late *now*... :

Does anyone have any expirenence with this TV? I have a friend with the
same tv.. Maybe I can borrow their AC adapter and try it on this one.

That's the *first* thing I would have tried (realizing that you
*could* possibly toast their brick in the process -- so hope it
is an understanding friend! :> )
Click to expand...

Well I was wrong about my friends tv. It was a newer version which included
the smps inside the case...

Anyhow. I managed to find 3 different supplies around here and wired them
all to the TV. It responded the same as before. A little noise from the
audio amp and the power light briefly flashed once.

I started probing around with the meter and can't see where this thing is
using the voltages to combine to make a floating voltage. What I can see is
they did use it to completely isolate the inverters from everything else.
The ground for the inverter is seperate as well. On the main PCB they have
2 circuits that have their grounds tied togeather. I think one is feeding
the tuner and one is feeding the audio amp.

Anyway.. I guess its on to trouleshooting the main pcb.

Mike
 
Michael Kennedy wrote:
Hi everyone..

I recently got a Sharp Aquos LC20E1-S LCD TV. The problem is it didn't come
with a power brick.
Click to expand...
So go to Radio Shack and get a dick sucking faggot ass power brick, then.
 
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