Re: Please help to fix this PA-1151-03HS-ROHS power adapter
I don't think those small caps or the mosfets are the problem anyway. Your issue is strictly on the primary side, it's where the AC voltage comes in, get rectified to DC then stored in the 400V cap.
Since the 19V DC output is only generated when 290V DC is present, and not when it's 170V DC, seems clear to me that either the bridge rectifier is failing or the 400V cap is.
Re: Please help to fix this PA-1151-03HS-ROHS power adapter
The voltage itself of 290v is completely wrong as written on the previous page.
Please measure your house mains voltage and see if you get a sensible reading.
Then a 12v battery and see if you get a sensible reading.
If you do we can assume the meter is ok and the only likely fault condition is the PFC stage.
Only problem with that is I don't know how fucked up it would need to be to generate such a voltage.
"The one who says it cannot be done should never interrupt the one who is doing it."
I don't think those small caps or the mosfets are the problem anyway. Your issue is strictly on the primary side, it's where the AC voltage comes in, get rectified to DC then stored in the 400V cap.
Since the 19V DC output is only generated when 290V DC is present, and not when it's 170V DC, seems clear to me that either the bridge rectifier is failing or the 400V cap is.
Please note, if the power supply is not connected to the computer, then sometimes, I can get 19V DC while the voltage of the 400V cap is fluctuating in between 210V and 170V. Then under such condition, once connected to the computer, the voltage of the 400V cap stays at 290V and the computer will be turned on (if last time the computer was off by itself) for a certain period of time. And then after manually turn off the computer, the voltage of the 400V cap drops and stays at 170V.
For the 400V cap, in my #10 post, I have mentioned that I added a 220uF 400V cap in parallel with the existing 150uF cap. Will this mean the problem is not from the 400V cap?
For the bridge rectifier, I have checked it on the board. There is no short and the forward bias is normal. Do I need to remove it from the board to check it?
The voltage itself of 290v is completely wrong as written on the previous page.
Please measure your house mains voltage and see if you get a sensible reading.
Then a 12v battery and see if you get a sensible reading.
If you do we can assume the meter is ok and the only likely fault condition is the PFC stage.
Only problem with that is I don't know how fucked up it would need to be to generate such a voltage.
Yes, I have checked my house mains voltage and my car battery and confirm that my meter is working properly. I have also used an analogue meter to confirm the voltage of the 400V cap are 170V and 290V under different situations.
set the meter to AC and meter the cap - it will show you the ripple/noise
My only experience in measuring AC was to measure the house voltage. And I do not know how to measure or know the ripple/noise. But anyway, I set the meter to AC and meter the 400V cap.
The first meter used was a digital meter. When the power supply is connected to main and to the computer but without being switched on, I found the reading was jumping from 78 V to 0V and from then again and again about once every second. When the computer was turned on, the reading was jumping from 4X V to 0V.
The second meter used was also a digital meter but less than $10. When the power supply is connected to main and to the computer but without being switched on, the reading was about 370V. When the computer was turned on, the reading was 600V.
The third meter used was an old analogue meter. When the power supply is connected to main and to the computer but without being switched on, the reading was about 200V. When the computer was turned on, the reading was about 390V.
It's really hard to understand.
Either the power supply is very modern and uses AC cycle skipping to increase efficiency.
Or it is broken.
Without knowing what the control chips actually are it is impossible to go further IMO.
Please see this thread to get an idea what cycle skipping is: https://www.badcaps.net/forum/showth...&highlight=PFC
Try to use a magnifying glass and read the chip numbers, it is not what you wrote in post #22, I can see that much from your photos...
My only experience in measuring AC was to measure the house voltage. And I do not know how to measure or know the ripple/noise. But anyway, I set the meter to AC and meter the 400V cap.
The first meter used was a digital meter. When the power supply is connected to main and to the computer but without being switched on, I found the reading was jumping from 78 V to 0V and from then again and again about once every second. When the computer was turned on, the reading was jumping from 4X V to 0V.
The second meter used was also a digital meter but less than $10. When the power supply is connected to main and to the computer but without being switched on, the reading was about 370V. When the computer was turned on, the reading was 600V.
The third meter used was an old analogue meter. When the power supply is connected to main and to the computer but without being switched on, the reading was about 200V. When the computer was turned on, the reading was about 390V.
Are there any indications from the above results?
the first meter makes me think the cap is bad.
the other 2 look like they where set to DC range.
very confusing.
Re: Please help to fix this PA-1151-03HS-ROHS power adapter
Cheap digital multimeters tend to give abnormally high readings if you apply DC while they're set to the AC volts range. If you measure a 9V battery on the AC range, you get 20V.
Re: Please help to fix this PA-1151-03HS-ROHS power adapter
Check my link in reply #29 lotas, within there I link to a Youtube video I uploaded showing AC cycle skipping in action: https://www.youtube.com/watch?v=M8ICFj07Tc0
The voltage jumps from 330v to 390v back and forth.
Obviously when voltage is decreasing no current is drawn from the grid so the leftmost meter shows 0w consumption.
It is a way to increase efficiency.
Unfortunantely I was unable to find a datasheet for the IC that you identified, so I don't know if this particular adapter supports it or not...
"The one who says it cannot be done should never interrupt the one who is doing it."
Comment