HP laptop P.S. stuffed with silicon? NO PROB!

[ben7]

Re: HP laptop P.S. stuffed with silicon? NO PROB!

Thanks Ben!!!!!!!!

I cut off 2.5" from the cable where it meets the P.S. board, soldered it back to the board, and I'm back in the saddle again!

So the short was around the area of the strain relief on the adapter? That is a common spot for failures in these cables.

[glutton4punishment]

Re: HP laptop P.S. stuffed with silicon? NO PROB!

The cord has a short inside it. You will have to get a new one. Or get the type of connector that goes into the laptop, and attach a new cord onto it yourself.

Thanks Ben!!!!!!!!

I cut off 2.5" from the cable where it meets the P.S. board, soldered it back to the board, and I'm back in the saddle again!

[ben7]

Re: HP laptop P.S. stuffed with silicon? NO PROB!

well there's a big diff from before, but I don't know what it means!

On the cap I measured before,(i.e., the one Bud told me to measure) it's 0.85 M ohms, and immediately slowly decreases in value. With the cord attached, it was 1.8 to 0.6 ohms, not M ohms.

On it's twin cap (the other output) it's 0.69 M ohms, and immediately slowly decreases in value.

Now what??

The cord has a short inside it. You will have to get a new one. Or get the type of connector that goes into the laptop, and attach a new cord onto it yourself.

Do this with the cord desoldered:
Put your meter on dc volts, and plug the charger in. Test the voltage across that capacitor. You should see a voltage there, and the ticking sound will be gone too.

[glutton4punishment]

Re: HP laptop P.S. stuffed with silicon? NO PROB!

Desolder the cord that goes to the laptop, taking note of which wire goes where on the pcb. Then, measure the resistance of those two points again. If there is no short, then the cord is bad.

well there's a big diff from before, but I don't know what it means!

On the cap I measured before,(i.e., the one Bud told me to measure) it's 0.85 M ohms, and immediately slowly decreases in value. With the cord attached, it was 1.8 to 0.6 ohms, not M ohms.

On it's twin cap (the other output) it's 0.69 M ohms, and immediately slowly decreases in value.

Now what??

[ben7]

Re: HP laptop P.S. stuffed with silicon? NO PROB!

with a DVM, it starts at 1.8 ohms, within a second drops to 0.6 ohm, and is steady there.

thanks for the help!

Desolder the cord that goes to the laptop, taking note of which wire goes where on the pcb. Then, measure the resistance of those two points again. If there is no short, then the cord is bad.

[glutton4punishment]

Re: HP laptop P.S. stuffed with silicon? NO PROB!

So yeah, let's try this again.

Please measure the resistance across the two points budm marked in that picture. The power supply doesn't need to be plugged into the wall.

with a DVM, it starts at 1.8 ohms, within a second drops to 0.6 ohm, and is steady there.

thanks for the help!

[ben7]

Re: HP laptop P.S. stuffed with silicon? NO PROB!

So yeah, let's try this again.

Please measure the resistance across the two points budm marked in that picture. The power supply doesn't need to be plugged into the wall.

[glutton4punishment]

Re: HP laptop P.S. stuffed with silicon? NO PROB!

post 18
"What DC resistance do you get measured right at two legs of either one of the output filter caps sitting at the edge of the board?" I post the picture with redlined to where to check the resistance, that is the output section,

Sorry, I don't have a big screen, and I didn't see any markings on the pic you quoted

I should be more clear about the power supply should not be connected when you do any resistance reading, but I assume the common sense to kick in for the tester know what to do when check the resistance in the circuit.

"It seemed to me that a teenager was trying to get me to short out the 400v cap to get me to either electrocute myself or get me to pull off a big bang and spark to scare the hell out of me." How did you assume that? I do not know where I indicate to short out the 400V cap!
All we are trying for you to do is to find out if you have shorted circuits in the secondary side but sure having a hard time with it.
I am out of here.

I already apologized. Thanks for your help/

[budm]

Re: HP laptop P.S. stuffed with silicon? NO PROB!

post 18
"What DC resistance do you get measured right at two legs of either one of the output filter caps sitting at the edge of the board?" I post the picture with redlined to where to check the resistance, that is the output section, I should be more clear about the power supply should not be connected when you do any resistance reading, but I assume the common sense to kick in for the tester know what to do when check the resistance in the circuit.

"It seemed to me that a teenager was trying to get me to short out the 400v cap to get me to either electrocute myself or get me to pull off a big bang and spark to scare the hell out of me." How did you assume that? I do not know where I indicate to short out the 400V cap!
All we are trying for you to do is to find out if you have shorted circuits in the secondary side but sure having a hard time with it.
I am out of here.

[kc8adu]

Re: HP laptop P.S. stuffed with silicon? NO PROB!

output=low voltage side.you likely have a short on the secondary(output)side.
rest assured that anyone suggesting you do something potentially deadly will get said post removed and a vacation!

[glutton4punishment]

Re: HP laptop P.S. stuffed with silicon? NO PROB!

What DC resistance do you get measured right at two legs of either one of the output filter caps sitting at the edge of the board?

If I misunderstood your intent, I apologize, and will remove my post.

It seemed to me that a teenager was trying to get me to short out the 400v cap to get me to either electrocute myself or get me to pull off a big bang and spark to scare the hell out of me.

If there was no bad intent, I'm sorry, but at the end of the day, I didn't understand what you wanted. I thought if I tried to measure the DC resistance, with or without current, I'd either get the spark/bang or fry my meter.

[kc8adu]

Re: HP laptop P.S. stuffed with silicon? NO PROB!

Wtf!

what reaction do you get when you swallow a 1/4 cup of granulated draino?

[budm]

Re: HP laptop P.S. stuffed with silicon? NO PROB!

A lot of power supply will put Zener diode for crow bar protection right at the output which will be in parallel with the filter caps, the Zener voltage will be 2~3V higher than the output voltage, it will crowbar the output and shorted itself out.
So far the symptom looks like the powers supply is trying to drive the shorted circuit (as other also had indicated) in the secondary side, unless it is the start up cap problem in the primary side (but with bad start up cap usually you will see some DC voltage pulses on the output filter caps).

[glutton4punishment]

Re: HP laptop P.S. stuffed with silicon? NO PROB!

What DC resistance do you get measured right at two legs of either one of the output filter caps sitting at the edge of the board?

what reaction do you get when you swallow a 1/4 cup of granulated Draino?

[budm]

Re: HP laptop P.S. stuffed with silicon? NO PROB!

What DC resistance do you get measured right at two legs of either one of the output filter caps sitting at the edge of the board?

[glutton4punishment]

Re: HP laptop P.S. stuffed with silicon? NO PROB!

The small one near the two large ones, and the two medium size blue ones on the left side. They say "Ltec" on them in cursive.

OK, I replaced the 3 caps. That wasn't the problem b/c I'm still getting no voltage at the output, and it's still making the beeping noise.

[glutton4punishment]

Re: HP laptop P.S. stuffed with silicon? NO PROB!

Unplug the the power to the brick, then check the resistance reading on the pins (+/-) of the DC jack of the brick to see if it shows really Ohm reading.

First I checked resistance of the P.S. cable from the 3 wires of the board on one end until the end of the P.S. cable that plugs in to the laptop. There are two black wires and one white wire on the board that lead into the cable that goes to the laptop. One white and one black wire show continuity from their respective connection points on the board to the outer metal jacket of the P.S. cable. One black wire shows connectivity between the connection point on the board to the inner pin of the P.S. cable

Resistance between the inner pin and the metal jacket that plug into the laptop shows infinite .

[budm]

Re: HP laptop P.S. stuffed with silicon? NO PROB!

Unplug the the power to the brick, then check the resistance reading on the pins (+/-) of the DC jack of the brick to see if it shows really Ohm reading.

[glutton4punishment]

Re: HP laptop P.S. stuffed with silicon? NO PROB!

the dc plug is shorted on that unit.very common.desolder the cord from the board and it will work if you have not damaged it.

I wish!! after I checked the voltage at the computer plug side, I checked the voltage at the pins at the P.S.

Zero voltage.

[kc8adu]

Re: HP laptop P.S. stuffed with silicon? NO PROB!

the dc plug is shorted on that unit.very common.desolder the cord from the board and it will work if you have not damaged it.