Re: Sorting out old PC power supplies?
160v??
where does that come from? he's got 340v dc after the rectifier.
160v??
where does that come from? he's got 340v dc after the rectifier.
-
-
Re: Sorting out old PC power supplies?
It should have been 340vdc, I overlooked that he was in the U.K. next time I will just call it Main B+
EDIT
The small smd transistor drives a larger mosfet that has it's Drain pin connected to the small standby transformer, I made a Red square around the standby mosfet and a yellow one around the drive transistor.
On the small standby transformer, pin 1 should have 340vdc, and so should pin3 which is connected to the mosfet drain., this is the primary. There is likely a low ohm resistor connected to THIS mosfet's source pin to hot ground.Last edited by R_J; 11-22-2020, 07:45 PM.Comment
-
Re: Sorting out old PC power supplies?
That's a great help RJ. Ok I took a reading on all you said and I dont get a voltage on Pin 1 of the standby transformer (my meter just goes straight to zero whatever that means) although I do get -310vdc on pin 4 and -310vdc at all 3 pins of the smd transistor.
I am not sure if I am putting the negative meter probe at the correct place. I am taking the negative from the negative output of the Rectifier but all readings are -voltages which seams wrong. I always get confused where I should be taking the negative from especially on the AC side. I guess if I take it from negative output of Rectifier its got to be right (I hope). I also get a high pitched sound when turning the PSU on or off. Its what sounds like its in pain lol...Comment
-
Re: Sorting out old PC power supplies?
high pitch sound usually means something is shorted.
check all ceramic capacitorsComment
-
Re: Sorting out old PC power supplies?
Did you remove the main capacitors at any time?
If you are getting - voltage I think at least one of the caps are in backwards, see this picture from the internet.
This schematic should help with the standby circuitAttached FilesLast edited by R_J; 11-23-2020, 12:37 PM.Comment
-
-
Re: Sorting out old PC power supplies?
Thanks RJ for that Schematic and thank you everyone for your help.
Thanks to you all I have finished repairing these PSU's and all the computers they go in are working again.
Thanks!Comment
-
Re: Sorting out old PC power supplies?
Some more items that did not land into the landfill
Go repairsComment
-
Vizio e601i-A3 - Has Sound and Display, But No Backlight - Bad Power Supply Board or Bad LED Bulbs ?I was given this TV from my great uncle. He said it just wouldn't turn on one day out of nowhere, replaced the TV, and gave it to me to possibly fix and use for myself.
Upon bringing it home and plugging it up, it showed a standby light.
I powered it on and without a flashlight, the display showed the "V" but the lighting is very dim, but visible.
The screen seems to blackout and stay black, but with a flashlight I can see the display.
With my Playstation 4 connected via HDMI, and running a game I can hear sound.
Assuming... -
Hi all,
TL;DR - this laptop is driving me nuts with the oddball power-related behaviors. Appreciate any insight you can provide!
I'm experiencing a power issue on an Asus Probook P5440UF-XB74. Although I've worked with electronics and computers for decades, this is my first attempt at getting into motherboard-level component troubleshooting. Any help the community can provide is greatly appreciated!
A few weeks ago I was using the laptop (on battery power) for a Zoom meeting. The battery was running very low (long meeting) but I wasn't worried about... -
Hi,
Back after a long hiatus with some old power supplies that need repairing. I've recently picked up a couple of 386SX systems, two 486DX systems, a SiliconGraphics Indy and an iMac G3 that either have verified leaking capacitors in their power supplies, or are likely to in the near future. For the sake of simplicity, instead of tackling all at once, I'm starting with the 386's and one of the 486's.
The 386's power supplies are Seasonic SS4040A's, with caps that are visibly leaking, and 9 replacement caps per unit are required. Most appear to be from the Rubycon... -
This specification for the HP Pavilion Power Pavilion Power 15-cb009nl Notebook can be useful for upgrading or repairing a laptop that is not working. As a community we are working through our specifications to add valuable data like the Pavilion Power 15-cb009nl boardview and Pavilion Power 15-cb009nl schematic. Our users have donated over 1 million documents which are being added to the site. This page will be updated soon with additional information. Alternatively you can request additional help from our users directly on the relevant badcaps forum. Please note that we offer no warranties that...09-06-2024, 05:59 AM
-
I have a Dell E5470 that powers up and boots windows no problem. Using a non-standard universal type charger, it shuts down immediately if moved, (power short in that charger or AC power jack) because the battery has no charge and isn't charging orange/white lights blinking on the front. When first powered up, BIOS power alarm stated that it could not detect the voltage setting and I had to dis-able the message to get past this. It got into Windows fine, as long as not moved, so I dis-assembled it looking for a cold solder joint on the power jack that I thought might be lifting off the MB, but...
Comment