I will do more testing later on this one later. I also took apart the other optiplex and found that it does have standby power, so I tried shorting the ground and PSON pins and it started up like normal with all power rails working. So I'm assuming the problem is with the mobo or power switch sending that signal.
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Good! So you know what value the broken components are!
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here we go again!
what is it with dell and these shit psu's with under-rated caps?
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Well unfortunately no. While both of these are 790s, one is 2nd gen intel and the other is 3rd gen. I noticed that some parts like the heat sync were slightly different but the PSUs look the same and are probably even interchangeable. When I opened the other one though it was completely different with an entirely different board layout.Comment
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I just hooked up the PSU to the mobo and manually turned on power. The front fan spins up but no other signs of life from the power button or LEDs. Is this a mobo issue?Comment
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some of the compact dell stuff is prone to bad caps on the motherboard.
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I am not sure what it is with the Dell SFF PSU’s, but they either blow to bits an sh*t, or they develop some weird faults. I got myself one of these special victims at work.Comment
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I've had more time to play around with them recently and was able to test the boards with an older optiplex psu that I had. Both boot up fine so it is an issue with the PSUs even though all power rails were working. I will probably just replace them rather than try and repair them.Comment
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if the rails are good then look at the supervisor chip that generates the PG signal
it may even be just cracked soldering linking one of the vertical sub-pcb's
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trace it from the connector
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I just checked and the PG rail outputs 3.88v. Is that the normal voltage?Comment
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https://linustechtips.com/topic/1562...-pg-value-huh/
it should go low initially and then jump up to 5v
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then you found the cause of the pc not starting.Comment
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no because it needs to pulse to ground first
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follow the signal, it may just be a bad transistor
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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.
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I have wanting to do this project for quite sometime now and I finally found a switching power supply that will work on this desoldering gun station ZD-915 that the original switching power supply took a shit and just was not worth trying to fix it because this switching power is not quite big enough to handle the heater element and the vacuum pump
One note when I tested the switching power supply and the voltage control board I noticed that this desoldering gun heat up much faster than the original switching power supply which I was really surprised by to the point that I might buy... -
Hello!
i got a damaged Manson NTP-5561 (60V, 1,6A DC output) and and the main issue is that the controler IC for the LCD display has a short. The controler IC PIC18F87K90 is mounted on the back of the back of the LCD. Vss-Vdd = 3 Ohm. The 5V and 3,3V power line was killed as well, but that is not a problem. A new LDO 3,3V and 5V 7805 is already ordered.
Replacing the PIC18F87K90 is necessary but that makes no sense without having the HEX dump of the new controler.
Does anybody have such a power supply and could do a HEX dump of the Flash and EEPROM memory?
...04-12-2025, 10:38 AM -
I have been working on this concept for quite some time now with limited success but recently I found a switching power supply that is setup for the voltage that this soldering station needs to operate at however it also needs part of the secondary circuit from the original switching power because you need several voltage rails
I once tried to get a ZD-915 desoldering station to work on a 18 volt battery power supply but unfortunately things did not go well but I did find a work around but I might try this idea again but going at a little differently more about this another time... -
The sub developed a constant popping every couple seconds from woofer and power LED flickering with nothing but wall AC connected. Connecting an audio cable didn't change anything. It doesn't play but a second or two of audio in between the pops.
Opened it up and discovered the power supply is making a faint clicking or ticking sound.
I measured the amp's output to the woofer and it pulses up to 50mv DC to be driver. The pulses coincide with the power supply ticking/clicking.
I measured the power supply output going to the amp board and it too has this pulsing. Voltage cycles...
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