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Dell power supply ADP-220AB B output schematic

How can I find out about the correct voltage at the Dell AC/DC Adapter utput plug that has 8 contacts? Brochure indicates the power output is 14v but I measure only 7.3 volts at one of the 3 plugs amongs those 8 plugs.

Thanks in advance for your help.

Albert

Posted by on

  • ammclam Oct 27, 2008

    Specific input voltages for this adapter are from 100 to 240 volts and output is 12 volts. I believe that the output should be 12 volts either at 120 volts or 240 volts, but I only got 7.4 volts. Do you think my adapter is defective?



  • Anonymous Feb 23, 2009

    I have just received a Dell SX280 with this adapter from the US, but I now live in Europe. Will it work??

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It may be possible that your adapter does not receive the rated power it should receive. You may have plugged your adapter to a 110 v outlet when the required input is 220 volts. See your adapter for the specific requirements.

Posted on Oct 26, 2008

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Trying to activate Dell P793 moniter using pc


If the monitor shows Power Saver Mode, or Sleep Mode, or No Signal; it is because it is Not receiving a Video Signal from the computer.

The monitor cable is bad, or the computer is not working.

http://support.dell.com/support/edocs/monitors/p793/En/specs.htm

http://support.dell.com/support/edocs/monitors/p793/En/index.htm

http://support.dell.com/support/edocs/monitors/p793/En/trouble.htm

The main problems with desktop computer failure is;
1) Computer is dirty inside
2) Power Supply failure
3) Ram Memory module/s ('Stick') are loose. Power unplugged from computer; FOLLOW Anti-Static Precautions; the Ram Memory module/s are removed, THEN reinstalled. Visual inspection WILL NOT DO.
(Also the gold plated contact pins should be cleaned with a pencil eraser. BOTH sides, ALL contact pins. Use air to remove eraser dust)

Just because you may see LED lights light, and Fans spin; means NOTHING.
Does NOT indicate the Power Supply is good.

A) If ALL of the LED's, (Light Emitting Diodes), were on at once, they would use less than 1 Watt of power.

B) EACH fan uses 2 to 3 Watts of power.

C) A typical Processor can use from 51 to 125 Watts of power. Just depends on what Processor it is. (Older Intel Pentium III's, and AMD Athlon's use less than 51 Watts of power)

This is why a Power Supply with a weak voltage power rail, can light LED's, and spin fans; but NOT have enough power to turn the Processor on.

[There are 3 main voltage power rails.
The Switched-Mode Power Supply (SMPS) in your computer is a Converter.
Converts high AC voltage, (100 to 240V AC) to 3 main low DC voltages;
3.3 Volts, 5 Volts, and 12 Volts. (DC)
In comparison two D cell flashlight batteries produce 3 Volts DC,

http://en.wikipedia.org/wiki/Computer_power_supply#Wiring_diagrams

http://en.wikipedia.org/wiki/Computer_power_supply

http://en.wikipedia.org/wiki/Switched-mode_power_supply

Suggestion is to test the 3 main voltages coming out of the Power Supply, with a multimeter set to DC Voltage.
You can buy an inexpensive multimeter that is plenty good enough for this job; for around $5 to $12.

OR;
Borrow a KNOWN to be good, Compatible power supply from a working computer; and use it temporarily for a test unit ]

If you are getting a video signal, and it is scrambled/distorted, post back in a Comment.

For additional questions please post in a Comment.
Regards,
joecoolvette

Dec 11, 2012 | PC Desktops

Tip

How to test your AC/DC Adapter or Computer Power Supply Unit.


A PSU or Power Supply Unit aka AC/DC adpater is then means by which a low tension (voltage) appliance receives its power from the 240 AV mains supply, the this is usually accompanied by the nominal current that is drawn from the PSU on load in milliamps. (e.g. 500mAmps = 0.5 Amps) most modern DC adapters are unregulated, where the output voltage is only regulated by the load current, and a smoothing Capacitor is sometimes used to reduce AC ripple on the DC Level.
If the PSU is regulated the DC Voltage that you measure using an AVO even off load will be the same as the rated current.

Also most, not all, are double insulated (indicated by small square inside a larger one) this means that it doesn't need a earth on the plug, the give away is a plastic pin instead of a metal one found in most domestic plugs with a 13A fuse.

Using Ohms Law P= I x V means that we can find out either the Current in Amps Power in Watts or the Voltage of any unit this is also called the VA rating

The Simple test is if the adapter gets really hot as soon as the you apply AC power then this may indicate catastrophic failure OR a dead short and you must turn OFF immediately the plastic may even start to melt, you may also smell electrical burning. This will also happen if you ever use a non-specific adapter on your device that has a different output voltage this will almost certianly cause damage to your device.

The main test if to test the step-down transformer using an AVO (Amps Volts Ohms) this is what is used to reduce the 240V ~AC voltage to something more in line with the required DC supply say 14-16V ~AC, a diode bridge converts this to DC, if it is regualted there will be either and either a zener or resistor drops this to the rated 12V and a capacitor to smooth the level.
You need to make sure this is socket is working correctly by checking with either a lamp electricians screw driver or a AC test plug, dont use this socket you have an earth fault or someother problem, usually two lines at the outside of a AC socket tester means all is correct.
  1. First measure the resistance (Ohms) across the two AC pins that is the Live and Neutral this should have VERY low resistance in the range 300 to 2,000 (2K) Ohms. if this is the case then your primary winding is probably OK if you see 1 on all settings this means open circuit (O/C)
  2. Then connect the power supply to a 240V AC socket, and check the output voltage with multimeter set at volts DC you should see a stable voltage of the rated value for a regulated adapter or slightly higher by about 5% if its unregulated as this is a reading off load, if you were able to test the voltage with the adapter on load you would see the rated DC voltage.
  3. If you connect an unregulated AC/DC adapter to the device and open up the cover to test it under load and the voltage is low around 5V or less then the adapter will need replacing even if the off load value appears correct in above test ( ** ref the table below)
NOTE: If you have a AC only output then the test done in 1 can also be done, if there is a diode bridge, Zener Dicde OR Capacitor on the secondary this test wont work so you might have to remove the cover by unscrewing the tamper-proof screws and test it before the connection to the PCB, without the power on of course, check out my tip HERE for help on how to remove the screws.

If you have a faulty power supply its usually the thermal fuse that blows on the secondary winding, this means that you will get considerably less Voltage at the output jack of around 5 VDC or less and falling if this is the case the transformer is faulty and will need to be replaced with one of the same step-down ratio. OR you will need a new AC/DC Adapter, check out this table for examples of the results that you might find.

f9329ce.jpg

** The Amstrad Black PSU that reports 24V and 383 Ohms on the primary may still not deliver the rated voltage under load and therefore I have marked this as a false positive and therefore FAULTY.

NOTE: The AC/DC Chargers are constant current devices (the symbol is usually two interlocking circles and even though you can do similar tests on the transformer primary coil its the current that it delivers under load that is important the only way to test this is using a clamp meter on the cable to see the current under load this should match the rated current.

COMPUTER ATX PSU

Most ATX power supplies are known as switched mode can only be tested under load when connected to the PC motherboard this is a bit tricky using a plain old Fluke, AVO or Multimeter the best way is to buy dedicated PSU tester for the type of Power Unit you have, it will check the DC voltages in the range + 12V,-12V,+5V,+5VBs and +3.3V on both the SATA and IDE supply cables these cost about £20 ($35) you can test the unit in as little as 5 mins.

on May 11, 2010 | PC Desktops

1 Answer

How to test a computer power supply out of the unit


AC voltage into it and DC voltages on at least one large plug---do not if got it out forget to look at the filter caps--seen some power supplies with several puffed up etc.


10_30_2012_8_37_19_pm.jpg10_30_2012_8_37_41_pm.jpg

Oct 30, 2012 | Dell PC Desktops

1 Answer

I have a dell computer. when i turn on the tower and monitor i get just a black screen on the monitor. i have pushed a few buttons on the bottom of the screen and it just says power save mode please use...


No, it's the Power Supply.

Power Supply has a weak voltage power rail.

The monitor goes to Power Saver mode because it is not receiving a video signal. (No Signal)
This is because the computer is not working.


Dell Support > Dimension 4700 desktop computer > Service Manual,

http://support.dell.com/support/edocs/systems/dim4700/sm/index.htm

Click on the heading - Advanced Troubleshooting

Is the Power On LED light blinking Amber? (Yellow)

Post back in a Comment.

Regards,
joecoolvette

{You can also test the power coming out of the Power Supply.

The Power Supply in your computer is an SMPS.
Switched-Mode Power Supply,

http://en.wikipedia.org/wiki/Switched-mode_power_supply

It converts the AC electricity from your home, or business, into DC electricity.
There are three main voltages produced;

A) 3.3 Volts (3 point 3)
B) 5 Volts
C) 12 Volts
All are DC voltage

Two D cell flashlight batteries produce 3 Volts DC.
(In case you are worried about being shocked.
The 'bad' electricity is contained inside the Power Supply's case)

If you do not have a multimeter, an economical unit can be purchased for around $8 to $12. A LOT of stores carry them. An auto parts store is one example.

Orange wires are 3.3 Volts
Red wires are 5 Volts
Yellow wires are 12 Volts.

ALL 3.3 Volt wires end at the same 3.3 Volt power rail in the Power Supply.
Same with 5 Volt wires, and 12 Volt wires.

You can test ANY Orange wire, or any Red wire, or any Yellow wire.

ANY Black wire you see is a Ground wire.

The red probe lead of the multimeter is the Positive lead. The black probe lead is the Negative lead.

The Positive probe lead is touched to a positive wire.
Orange, Red, or Yellow.

The Negative probe lead is touched to ANY black wire. ALL black wires are a Ground wire.

The function knob on the multimeter is set to DC voltage. (Dotted line over a solid line, with a dotted line under the solid line. The curved S line over a solid line is for AC voltage. This = No)

If there are different scale settings, set the function knob to 0-50 Volts. (DC)

Aug 24, 2011 | Dell Dimension 4700 PC Desktop

1 Answer

My Dell Inspiron 537s stopped working and won't turn on. There is a green light in the back when I plug it in, but the power button in the front does nothing. I am assuming it is the power supply, but...


The only way to determine if the power supply is no good without replacing it is to get a Volt Meter and test the Output on the current Power Supply. If you are getting the correct Output Voltage (correct Output Voltage may vary from computer to computer) then it is not the power supply, but if you are getting a 0V then your power supply might be damaged or blown a fuse, or just simply dead.

You can try to see if you can buy a power supply with a return policy just to see if that fixes the issue.

Please rate if this helps

Mar 15, 2011 | Dell Inspiron 537s (DDCWRA2_6) PC Desktop

1 Answer

I have a dell dimention 5100 it was working fine this morning. But now i can turn it on.


Suggest you bypass the Power On switch with a jumper wire used on the Soft Power On of the Power Supply.

If the Power Supply comes on, you have a bad Power On switch.

If the Power Supply does Not come on, you have a bad Power Supply.

The Power On switch is located inside the plastic Power On button.
This is one generic Power On switch that I have found fits many computers,

http://www.directron.com/atxswitch.html

The jumper wire is used on the 24-pin ATX main power cable.
This is an example of a 24-pin ATX main power cable, and it's connector,

http://www.playtool.com/pages/psuconnectors/connectors.html#atxmain24

Dell Support > Dimension 5100 > Technical Overview > System Board Components,

http://support.dell.com/support/edocs/systems/dim5100/en/sm/techov1.htm#wp1058472

The 24-pin ATX main power cable is plugged into the motherboard, as shown in the photo to the right, on the Playtool link.

The jumper wire is used to make a Momentary (Brief) contact, with the green wire, and ANY Black wire.

The Green wire is the Soft Power On wire.
ANY Black wire is a Ground wire.

There is a correct procedure for doing this.
The safety risk is very minimal.
The Soft Power On voltage is 5 Volts DC.
Two D cell batteries produce 3 Volts DC.

An insulated wire should be used. You may wish to wear a glove on the hand that connects the jumper wire, just for an added feeling of safety.

Should you wish to know the correct procedure, simply state so in a Comment. Believe upper right of your page.

Jun 24, 2010 | Dell Dimension 5100 (D51L1) PC Desktop

1 Answer

Dell dimesion 8300 desktop--ac power alert when computer boots up


  • makes sure that the AC cord the you are using is compatible with the PC
  • and the right output / input settings are correct check the power supply voltage settings

Apr 24, 2009 | Dell Dimension 8300 PC Desktop

1 Answer

Hi; I Have a Dell XPS 1530 which is dull if I do not have it plugged in. I have three Targus power cords and cannot use any of them. The one that has the S35 tip fits, but only engaged...


I am showing the AC adpater specifications as:
Input Voltage Range: AC 100V - 240V
Output Voltage: DC 19.5V
Output Current: 4.62A
Power: 90 Watt
Does your adapter meet those specifications?
Although I am a proponent of Targus products, possibly purchasing an OEM adapter may solve the problem. We have successfully purchased ones available from reputible vendors on eBay at a discount.
Have you checked to always show the battery status in the system tray so that you can verify when the AC adapter is actually charging versus an intermittent connection or malfunctioning power socket?

Oct 22, 2008 | PC Desktops

2 Answers

Power supply will not charge battery on lattitude d 510 laptop


It may not be the power supply. The Battery can only take 500 charging cycles in it's lifetime. the battery could have failed or the chip on the motherboard that regulates voltage to the battery may have failed.

Easy test for power supply is with battery removed if it still powers up the laptop than the voltage and amperage are sufficient.

Mar 27, 2008 | PC Desktops

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