Repair HP 510 laptop charger guide help

[coolcurrent]

I need some help repairing hp510 laptop charger.

if anyone can help me with schematics, and repair steps or good,

i should be fine

thanks

[weirdlookinguy]

Re: Repair HP 510 laptop charger guide help

Give us some pics of the adapter, inside and out, and what is wrong with it.

[coolcurrent]

Re: Repair HP 510 laptop charger guide help

the laptop charger is blown.
specs

Rev: A09
CT:121C52FVU868YR
input: 100-240v ~ 1.6A
Output: 18.5v ~ 3.5A

A capacitor is blown 47uF 400V, but i can't find an exact replacement.
it has two ICs one 8pin double dip ic, and 4 pin double dip ic

is this specs enough? Please help

[momaka]

Re: Repair HP 510 laptop charger guide help

47uF, 400v? Sounds like the primary capacitor. If that cap is visually blown, there may be other damage on the primary side. Check the fuse, bridge rectifier and main switching transistor. If possible, post some (decent) pics so we can point at things to check.

If you're in the USA, Digikey and Mouser will likely have an equivalent replacement for that cap.

[coolcurrent]

Re: Repair HP 510 laptop charger guide help

47uF, 400v? Sounds like the primary capacitor. If that cap is visually blown, there may be other damage on the primary side. Check the fuse, bridge rectifier and main switching transistor. If possible, post some (decent) pics so we can point at things to check.

If you're in the USA, Digikey and Mouser will likely have an equivalent replacement for that cap.

here is a picture i took from my phone. is this ok?

[momaka]

Re: Repair HP 510 laptop charger guide help

Is this the original power adapter that came with the laptop? Sure looks like a cheap no-name brand, judging by the "Velta" label on the transformer (I'm guessing they tried to make the name sound like Delta, which is a reputable PSU manufacturer).
Probably not worth fixing considering how cheap it looks, but let's look into it anyways...

I think the bridge rectifier should be the black box with 4 pins between the power plug and blown cap (the bottom one, on left side of the picture). If you have a multimeter, check it. One way you can do this is to put the meter on continuity/diode check and place the probes on the pins labeled AC on the bridge rectifier (usually the 2 inner pins). If the bridge rectifier is bad, your multimeter will show short circuit/zero resistance. Also place the red probe of your multimeter on the positive (+) pin of the bridge rectifier. Then if you place the negative probe on either of the two AC pins, you should not get any short circuit readings. Repeating this for the black probe on the negative (-) pin of the bridge rectifier and red probe on either AC pins, you should not get any shorts again.
Check the fuse as well - should be located between the power plug and the coil (left side of the pic), though I cant tell for sure because the picture is a bit blurry.
If all these test good, replace the 400v cap. Just make a note of its height and diameter so you can buy a suitable replacement. Actually while you're at it, replace the other caps as well if they are some unknown brand.

[coolcurrent]

Re: Repair HP 510 laptop charger guide help

i removed the rectifier coded D2SB60, and tested the inner ac pins both ways, but did not get any reading, i guess this means not bad right?

There is a resistor connected between one pin from the ac input, to the small black coil near the ac input, with color code brw-blk-brw, with blue body, did not give any ready. Isn't this suppose to be 100ohms?

Placing the red probe of the multimeter on the positive (+) pin of the bridge rectifier, and then placing the negative probe on either of the two AC pins gives reading of about 3ohms each.

[momaka]

Re: Repair HP 510 laptop charger guide help

Placing the red probe of the multimeter on the positive (+) pin of the bridge rectifier, and then placing the negative probe on either of the two AC pins gives reading of about 3ohms each.

Bridge rectifier is shorted. A good one will show open/infinite resistance in this setup (out of circuit, at least). Just to double check, reverse the probes and see what reading you get - if you get 3 ohms again, it is definitely shorted.

There is a resistor connected between one pin from the ac input, to the small black coil near the ac input, with color code brw-blk-brw, with blue body, did not give any ready. Isn't this suppose to be 100ohms?

Yes, a resistor with a brown-black-brown color code is 100 Ohms. However, I think this might be a fuse and not a resistor - it just makes more sense if it is. Question - does the prefix for this component start with "F" or "R"? "R" would indicate a resistor, and "F" would indicate a fuse. It could also be a fusible resistor, but I doubt it. The color code could be the current rating.

Lastly, while you have the bridge rectifier out, check the resistance between the (+) and (-) pins of the primary capacitor. If you get a short or fairly low resistance, remove the cap and measure those same spots on the PCB again. If you keep getting short/low resistance, the primary transistor may also be bad, along with other parts.

[coolcurrent]

Re: Repair HP 510 laptop charger guide help

Bridge rectifier is shorted. A good one will show open/infinite resistance in this setup (out of circuit, at least). Just to double check, reverse the probes and see what reading you get - if you get 3 ohms again, it is definitely shorted.

putting the negative of the multimeter probe on the (+) of the rectifier and the positive on any of the ac input doesn't give any readings.

Yes, a resistor with a brown-black-brown color code is 100 Ohms. However, I think this might be a fuse and not a resistor - it just makes more sense if it is. Question - does the prefix for this component start with "F" or "R"? "R" would indicate a resistor, and "F" would indicate a fuse. It could also be a fusible resistor, but I doubt it. The color code could be the current rating.

yes there is an F in below the resistor on the pcb

Lastly, while you have the bridge rectifier out, check the resistance between the (+) and (-) pins of the primary capacitor. If you get a short or fairly low resistance, remove the cap and measure those same spots on the PCB again. If you keep getting short/low resistance, the primary transistor may also be bad, along with other parts.

i already removed the capacitor, because it was swollen badly, and i get a reading of about 3-5ohms both ways reading. There is a transistor LRF1840G on the board.

[momaka]

Re: Repair HP 510 laptop charger guide help

yes there is an F in below the resistor on the pcb

It's a fuse then, not a resistor. Just need to figure out what it is now .

i already removed the capacitor, because it was swollen badly, and i get a reading of about 3-5ohms both ways reading. There is a transistor LRF1840G on the board.

That reading indicates a problem, unfortunately. Remove the transistor and measure those spots again. Also check transistor for shorts, particularly between Source and Drain.

putting the negative of the multimeter probe on the (+) of the rectifier and the positive on any of the ac input doesn't give any readings.

Any chance the probes on your multimeter are reversed? Black probe should be connected to COM. The results above seem reversed. Also, are you checking the bridge rectifier with diode test on your multimeter or just measuring resistance? If resistance, set it to 2 kOhm setting.

Some more tests to perform on the bridge rectifier:
-If you put red probe on positive (+) and black probe on negative (-), you should get no reading/open circuit/infinite resistance. Reversing the probes should give a reading but not a short circuit.
-Also try black probe on the negative (-) pin of the bridge rectifier and red probe on either AC pins. Should read open/infinite resistance again and reversing the probes should give a reading.

[coolcurrent]

Re: Repair HP 510 laptop charger guide help

hello i did some more test and found this

this transistor TL431A was shortened but i can't find it. is there an equivalent?
there is an IC UC3842 but don't know its function or how to determine if its bad.
there are two transistor like components connected to the heat sink with number LFT184G

any help?

[Badcappy]

Re: Repair HP 510 laptop charger guide help

1. TL431 is a voltage reference. See
2. UC3842 is the PWM controller.
3. From what you said, your rectifier seems OK. The polarity of ohmmeter probes varies between manufacturers. It's fine if and only if there's continuity between (+) and both (~) in only one direction, and between (-) and both (~) only in the opposite direction.
4. The resistor with a blue body is a wirewound type being used as a fuse. Either way, it should not be open.
- Your primary reservoir capacitor is shorted. That's likely what caused the above to blow.

Trace out a schematic of the primary side to figure out where everything is; it won't be very complex. The "two transistor like components connected to the heat sink" would probably be the primary switchers --- they'll also be connected to the driver IC and the transformer.

[momaka]

Re: Repair HP 510 laptop charger guide help

The "two transistor like components connected to the heat sink" would probably be the primary switchers --- they'll also be connected to the driver IC and the transformer.

I think this adapter uses a single-transistor forward configuration - i.e. there's only one transistor connected to the transformer on the primary side. Perhaps the other "transistor-like component" is a schottky diode for the output on the secondary side. Hard to tell from the picture, unfortunately. Check the numbers again. LFT184G doesn't return anything.

I couldn't find anything with the number LRF1840G either, but I did find something for 1840G - it's a N-channel MOSFET, rated for 8.8A in pulse mode. Seems about right for this application, minus the 200v Drain to Source voltage rating, which appears low (it's typically 600v and above for adapters/devices like this).

Yes, UC3842 is the PWM controller, and this is its schematic:
http://www.datasheetcatalog.com/data...8/UC3842.shtml
You can do a really simple test on it to see if it's shorted. Again with your multimeter, check for a short circuit between Vcc (pin 7) and Ground (pin 5). There shouldn't be any.

Also, remove transistor (the lower one not attached to the heatsink) and measure resistance where the primary cap connects. A fairly large resistance should be present or perhaps even appear as open circuit.

For TL431, you can find a replacement one in just about any junk computer PSU.

Last but not least (and I hate to ask this) I think we may need some better pictures, preferably one with the underside showing all of the traces and another one of the top side. If you don't have a better camera, try putting a magnifying glass in front of the current camera you have. This should allow you to take more focused pictures from a closer distance.

[coolcurrent]

Re: Repair HP 510 laptop charger guide help

hell thanks for resonding

the two transistor like device one is LRFI840G not LRF1840G and the other one is F10P10Q

there is one more device i don't have idea how to test D835. seems to be an opto device

I can't find TL431 for now but if there is any alternative ls let me know

[momaka]

Re: Repair HP 510 laptop charger guide help

Here you go, TL431 replacements at Digikey (you can likely find them at other electronics sites as well, such as Mouser):
http://search.digikey.com/scripts/Dk...296-17374-1-ND

I think the transistor labeled "LRFI840G" should be IRFI840G actually. With that, Datasheetcatalog gives results for a 500V N-Channel MOSFET in a TO-220 Fullpak case - looks like the right part for this application.

As for the part labeled F10P10Q, check the label on the PCB - does it have a "D" prefix, "Q" prefix, or something else. D would indicate a diode, Q a transistor. I'm thinking this could be the output rectifier, perhaps a F10C10. Is it located on the secondary side close to the output caps and output wires of the adapter?

Lastly, is D835 the name of the component or the marking on the PCB for that component? Number of pins?

[coolcurrent]

Re: Repair HP 510 laptop charger guide help

Thanks to all the guys that helped, I FIXED the charger!!!
This is what i changed

The fuse
the power capacitor 47uF, 400v
the transistor TL431A
the IC UC3842

[severach]

Re: Repair HP 510 laptop charger guide help

The TL431A is a programmable shunt regulator or a shunt voltage reference. It may be shaped like a transistor but it isn't.

[momaka]

Re: Repair HP 510 laptop charger guide help

Congrats on fixing it!

So, what did you end up replacing the fuse with (amp rating)? Also, what brand/series of cap did you use for the 47uF, 400v primary cap? Just curious in case I or someone else runs into a similar adapter. Thanks.

By the way, be careful with this adapter - it's obviously cheaply designed and lacks almost all protection circuits such as over-current/over-load, over-voltage, and under-voltage. If I were you, I wouldn't use it at close to its rating.
There's another smaller cap on the primary side - likely a 10uF, 22uF, or 47uF at either 25v or 50v (next to the 47uF, 400v cap you replaced) - if that one fails, the adapter would appear dead. Might be worthwhile to change it now, even though the adapter works. Same with the two output caps.
Of course, if you don't plan on using this adapter to power anything important, you can leave it as is.

[coolcurrent]

Re: Repair HP 510 laptop charger guide help

i couldn't get a fuse to replace so i use a strand of flexible wire as fuse
i replaced the capacitor with the same values the brand name on the capacitor isn't clear something like "lelav"

ok i will change other capacitors as well

thanks

[meanderer]

Re: Repair HP 510 laptop charger guide help

that's what they have inside?

I would get a reputable brand laptop charger instead.

newegg has an antec 65w for about 25.