hp probook 6570b no power

[dqtech]

the problem is 3v and 5v not present....i've check on controller ic Tps51125a (u1001), vreg3 0v and vreg5 only read 1.8v...any help?

[mon2]

Re: hp probook 6570b no power

Schematics should be posted only in the dedicated schematic forum and linked here. It will make it easier to locate by future readers.

Remove all power. Meter in resistance mode.

Measure the resistance to ground of vreg5 (since it is not the full 5 volts).

Repeat for vreg3.

Post both measurements along with the resistance scale / units.

[dqtech]

Re: hp probook 6570b no power

Schematics should be posted only in the dedicated schematic forum and linked here. It will make it easier to locate by future readers.

Remove all power. Meter in resistance mode.

Measure the resistance to ground of vreg5 (since it is not the full 5 volts).

Repeat for vreg3.

Post both measurements along with the resistance scale / units.

hi sir....sorry i give wrong information at the beginning....this is the right measurement....vreg3 read 1.8v (resistance 50k ohm) and vreg5 read 0v (resistance read short 4 Ohm only)

sorry i cant edit post for that schematic....here the link https://www.badcaps.net/forum/showth...61#post1273961

[mon2]

Re: hp probook 6570b no power

Vreg5 has a shorted component on this rail.

Use a dc power supply dialed to 1 volt (not higher) and inject this voltage onto the vreg5 rail.

No other power to the logic board. This part at 4ohms should start to heat up.

(Revised)

[dqtech]

Re: hp probook 6570b no power

Vreg5 has a shorted component on this rail.

Use a dc power supply dialed to 1 volt (not higher) and inject this voltage onto the vreg5 rail.

No other power to the logic board. This part at 4ohms should start to heat up.

(Revised)

can inject on this SL1001 right?

[dqtech]

Re: hp probook 6570b no power

feel a bit warm on controller ic 51125A (U1001)

[mon2]

Re: hp probook 6570b no power

Locate the pcb pad at SL1001. It is very likely to be a small trace between pads. If it is a part (0402) on the pads, flux and remove it. Sometimes, the 0 ohm in an 0402 package is used as a jumper. By removing or cutting this connection, the vreg5 rail will be isolated from the load side.

If it is a PCB trace, you can consider to cut the trace for a quick test. Afterwards, you can solder blob the cut trace pads to restore back to original.

Then measure the resistance to ground again of this vreg5 rail with the cut trace.

The fault may be with this regulator IC or a component on this power rail.

[dqtech]

Re: hp probook 6570b no power

Locate the pcb pad at SL1001. It is very likely to be a small trace between pads. If it is a part (0402) on the pads, flux and remove it. Sometimes, the 0 ohm in an 0402 package is used as a jumper. By removing or cutting this connection, the vreg5 rail will be isolated from the load side.

If it is a PCB trace, you can consider to cut the trace for a quick test. Afterwards, you can solder blob the cut trace pads to restore back to original.

Then measure the resistance to ground again of this vreg5 rail with the cut trace.

The fault may be with this regulator IC or a component on this power rail.

i remove jumper SL1001, vreg5 read 47 Ohm....restore back to original read only 4 Ohm

[dqtech]

Re: hp probook 6570b no power

problem solve....i replace that regulator IC and everything work fine...thank you sir