The Asus Eee PC Top ET1602C All-On-One Desktop PC, is set up like a laptop.
All the hardware components are in the main unit.
This includes the Power Board. (Power circuit on the motherboard)
Part of the power circuit is the external AC adapter that you plug in.
Test the output voltage of the AC adapter.
Use a multimeter.
[An inexpensive multimeter can be purchased for as little as $5 to $12. Available in a multitude of stores. An auto parts store is but one example. Some chain stores have them in their checkout aisle racks]
AC adapter plugged into power, not plugged into all-in-one.
The center hole of the plug is the Positive connection.
The cylindrical metal outside shell is the Negative connection.
Function knob to DC Voltage.
[If just a symbol, it is a dotted line over a solid line. Fairly expensive multimeters have an auto detect feature, that senses if it is AC or DC]
Positive (Red) probe lead of multimeter goes to center hole.
Negative (Black) probe lead to outside cylindrical metal shell.
You should read 19 Volts DC.
Also while testing have an assistant gently wiggle the cable from AC adapter to all-in-one, and the power cable to AC adapter.
Fluctuation of reading indicates broken wire/s in that cable, or power cord.
Replace AC adapter if voltage low, or cord/cable damage.
One example from a quick search,http://www.ebay.com/itm/AC-Adapter-Charger-For-Asus-EeeTop-PC-ET1602C-ET1601-Notebook-Power-Supply-Cord-/390467777452?pt=Laptop_Adapters_Chargers&hash=item5ae9b173ac
AC adapter checks out OK?
The port on the all-in-one that the AC adapter plugs into, is a DC Power Jack.
Suggest use the eraser on a No.2 pencil, and gently see if you can move the center pin around.
If so see if the center pin itself moves, or it seems the entire DC Power Jack moves.
Center pin moves indicates replacement of DC Power Jack.
Entire DC Power Jack moves, MAY just indicate the solder connections for the DC Power Jack to motherboard; may just need to be re-soldered.
DC Power Jack external inspection reveals it is OK?
On the motherboard are electronic components, that deal with the input DC Voltage.
Power MOSFETs, and Ceramic Capacitors to be more specific.
Using an ESD wrist strap, and having it connected to a good ground source, (Average price $3 to $6), the all-in-one is opened up, and electronic components are visually inspected.
Inspected to see if they are blackened, burned, or blistered.
Components are replaced if damaged.
If this is not in your line of expertise, then suggestion is to replace motherboard.http://www.ebay.com/itm/Asus-27-ET2700-04-ET2700I-All-In-One-Computer-Mother-Board-/130769666691?pt=Desktop_PCs&hash=item1e727ac283
No not your motherboard. Just posted to give you a 'feel' what prices may be like.
Opening Case of All-In-One;
I do not have access to a direct Service Manual, nor have I worked on this model.
Very FEW all-in-one computer manufacturers EVEN post, any such information, and speaking of all; all-in-one computer manufacturers.
The usual route is to remove the Back Stand, then the Back Cover Enclosure.
Look for Philips head screws hidden under paper labels, or thin plastic covers; plus any visible screws when going to remove the Back Stand.
May also be a clip you depress after removing screws.
The Back Cover Enclosure is held on by Philips screws which surround it's outside perimeter.
(Suggest lay the LCD screen side down on a soft cloth, on a table to protect it; and be in the correct position for this procedure )
The Back Cover Enclosure also has Latches around the inside, of it's outside perimeter. These snap into Tabs located on the Front Cover Assembly.
Sometimes it's a lot of fun(?) trying to release these Latches.
A flat tipped screwdriver is used, with EXTREME caution.
The tip is ONLY inserted just so far, and the prying action is used with finesse.
[BETTER tool to use is a Spudger Tool,http://www.ifixit.com/Tools/Spudger/IF145-002
If the screwdriver does not insert at the point you are trying, it may be because you are at one of the Latches. Move over.
Finesse is used, because the Latches are now brittle from over time, and constant heat from inside the computer.
Even if you use great finesse, do not be surprised if a few of them get broken.
Tech or not, brittle plastic breaks.
It will be OK as the Philips head screws will 'keep everybody together'.
Guides using HP/Compaq All-In-Ones as examples. Glean from them in opening yours, (Ones that are listed as All-in-ones),
Note that everything comes off in 'layers'. Metal static shields, optical drive, harddrive, etc.
To replace the LCD screen for example, you have to completely disassemble from the back to the front, then you can access the screws which hold the Display Screen Bezel in place. The Screen Bezel is removed, THEN the LCD screen can be removed from the front.
[Watch me be mistaken with this model, and there IS a way to access the LCD screen from the front, lol! ]
Here are basic examples of components on the motherboard, that you may find to be bad,https://docs.google.com/viewer?a=v&q=cache:oER5NNz8cwcJ:www.fairchildsemi.com/ds/FD/FDS6675BZ.pdf+Fairchild+FDS6675BZ&hl=en&pid=bl&srcid=ADGEEShOhWPjm_M-ROHme4iEMrztCTOd-28jNiy1hVLQQh_VOyv8zcXEVDB_iTQA6MuZO88UmRkDgjyW9j4CP2aIJ-4DS-h6JNM3lvxldeApQeecmz_DADCw1s7tmNLxfPknqX14SZP6&sig=AHIEtbS_rYUAeo_8rB9YHkW05ZjLqeH4Jg
Average cost of a Fairchild Semiconductor - FDS6679 - Power MOSFET,http://www.mouser.com/Search/Refine.aspx?Keyword=FDS6679
One dollar, and one penny, USD.http://www.mouser.com/Passive-Components/Capacitors/Ceramic-Capacitors/Multilayer-Ceramic-Capacitors-MLCC-SMD-SMT/_/N-b2cj?P=1z0wrkrZ1z0vhw8
Average price 63 cents to 80 cents USD.