Lenovo Think center A70z PSU issu

[sourcebf]

Hi for all,

I have Lenovo Think center A70z with power issu, I try it with my power bunsh and it work perfectly.....

i mesured PSU Vout and it is 19v ...seems to be ok but it can't start my AIO,

when i push the power button I hear "click""" click and power led blinks but AIO not power on...

please can someone help me, i attached pictures of my PSU

[sourcebf]

Re: Lenovo Think center A70z PSU issu

any help please...

[PeteS in CA]

Re: Lenovo Think center A70z PSU issu

If the output voltage of the adapter is 19V when it is plugged into your computer, the problem is probably in the computer rather than in the adapter.

[sourcebf]

Re: Lenovo Think center A70z PSU issu

If the output voltage of the adapter is 19V when it is plugged into your computer, the problem is probably in the computer rather than in the adapter.

But I used my Power lab and the computer works fine....

[vinceroger69]

Re: Lenovo Think center A70z PSU issu

can you place a load on the faulty psu and see if it shuts down what amps did you have you bench power supply set at

[sourcebf]

Re: Lenovo Think center A70z PSU issu

can you place a load on the faulty psu and see if it shuts down what amps did you have you bench power supply set at

my power lab is 30V 3amps max
I disconnect all devices befor test with power lab, i just leave:
- board
- 1 cpu fan
- lcd without backlight

AIO start and i saw Thincenter logo, bip post ok

i set power lab at 19V and i have 2.5 Amps consomation.
I tried it with the PSU in the same conditions, when i push power button 19v goes to 11v....13v...10v......12v.. ?????

[PeteS in CA]

Re: Lenovo Think center A70z PSU issu

Putting together things you've said, it sounds like the adapter is in regulation (19V) with no load. But when you try to load it, it is out of regulation and not very stable.

If you are measuring the voltage at the computer input, you may have a bad connection between wherever circuit senses and regulates and the computer (for example, a partially broken wire in the output harness or connector to the computer or a bad solder joint where the harness wires solder to the adapter PCB).

If you are measuring at the adapter PCB, there may be a bad connection between where you are measuring and the output from the transformer, or on the primary side. Another possibility is that the circuit oscillates if you try to load it. You would need an oscilloscope to check for oscillation.