Help needed to revive dead HP AC adapter

[mikey5791]

Hi all,
Got this HP AC adapter model HSTNN-CA15(output 19.5V, 3.33A) for HP laptop which suddenly died yesterday.
Opened the adapter casing and did not find any burning part, loose or broken wire but the square T3.15A fuse still has continuity.

I pulled out the biggest green resistor nearest to main cap at CX2. The resistor has 5 band which is red,red,gray,gold,white. Is this a 22.8 ohm 0.5w type resistor(lenght abt 1 cm)? Please correct me if i m wrong. It measured about 0.4 ohm on dmm, so it is bad. I have no exact replacement so i use a 30 ohm 2w from my stock but the adapter still has no output.

Appreciate anyone with experience to kindly guide and assist on how to revive this dead adapter and not adding to the dumpster instead.

[CapLeaker]

Re: Help needed to revive dead HP AC adapter

Nah… to 99.9999% resistors don’t go lower in value. Since the fuse isn’t blown, check the secondary output for an open in the cable or a short on the rectifier diode.

Red, red, silver, gold is 0.22 Ohms. The rest you read is probable resistance in your leads. If that resistor would be blown, it would have taken the fuse with it. So stick that old resistor back in there.

[stj]

Re: Help needed to revive dead HP AC adapter

probably bad cable - it looks like a 3wire one.
1wire eeprom model??
the eeprom can die/be killed in those and then you get voltage but the laptop can ignore it.

[mikey5791]

Re: Help needed to revive dead HP AC adapter

CapLeaker,
I put back the old resistor and check for short on rectifier diode.
Did not find any short so far.

Stj,

yes, the output cable is a 3 wire type.
The black wire marked RTN should be negative ground, the white wire marked VOUT should be positive output while the blue wire marked ID_PIN (not sure what is this for).

Sorry i do not understand what you meant by 1 wire eeprom model...
I did power on again after putting back the resistor and make sure no shorts on rectifier diode and the square fuse still has continuity. But still no output on the output pin. I use dmm on dc mode to measure the 2 main cap and there is no dc voltage as well. I wonder maybe the 4 pin bridge rectifier could be bad.How do i test it?

[mikey5791]

Re: Help needed to revive dead HP AC adapter

CapLeaker & stj,
You guys are right in giving those helpful hints.
Is the bad 3 pin AC power cable.
Haha, i did not test the continuity of the power cable assuming it is good. But apparently the live and ground were broken somewhere. That is the cause of no power.

[CapLeaker]

Re: Help needed to revive dead HP AC adapter

Yeah… experience comes handy… glad you found the problem.