Re: Modify output voltage of a Dell power brick
Thanks for the warning guys. In my case I modified the lower resistor.
I have another 65W Dell brick that I'll try the modification on. Hopefully I won't destroy that 2nd one. I kinda lost motivation however...
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Re: Modify output voltage of a Dell power brick
Thanks for the suggestion Tom but the output voltage was set for 17V (nominal was 19.5V). I can't go higher because 17V is the max my charger will support. I nvereless tried to increase the voltage but it doesn't help. Looks like I broke it somehow.
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Re: Modify output voltage of a Dell power brick
Well if anyone is still following this thread, the success was short lived. I reassembled the brick and it actually worked to power my battery charger (my intended application) and charge one battery yesterday. Today I tried to plug it into another charger and it only worked for a few seconds. After that the voltage started slowly decreasing and goes to near 0 within maybe 5-10 seconds. I disassembled it again and everything seems intact but yet not working.
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Re: Modify output voltage of a Dell power brick
Bingo! Tweaking R25 and R26 did the trick! Now I just need to replace the pot I used for testing with a fixed resistor. Or maybe leave the pot there to create an adjustable power supply.
Any idea what voltage range I could expect?
Thanks everyone for your help on this, especially budm!
Now that I found this nice forum I could maybe try to fix an old massive 13.8V, 270W supply that I got. It's even got the schematics inside of it so I'm sure I could fix it with you guys help.
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Re: Modify output voltage of a Dell power brick
Ok, here's some partial reverse engineering of some of the traces. I concentrated on one optocoupler to start with.
I drew it to ressemble the "typical" circuit posted earlier. I think that I have everything I need. I'll try to tweak R25 and R26....
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Re: Modify output voltage of a Dell power brick
Attached is the result of some more probing.
Here's what's written on the outside:
65W AC ADAPTER
Model HA65NS1-00 Rev : A01
Output 19.5 V, 3.34 A
PA-12 Family
Thanks for the offer to open yours up but I'm more than willing to simply probe mine with your instructions....
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Re: Modify output voltage of a Dell power brick
I probed the board and identified any point directly connected to Vout, in case that helps out. I'm guessing that the voltage divider will be connected to one of these points.
The p/n of IC32 is very hard to read. I think it's LA1 and there's a symbol on the left of it that looks like a backward N....
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Re: Modify output voltage of a Dell power brick
Thanks budm for the diagram. Here are two more pictures that should help.
I just thought about something. I had to replace the DC jack for a smaller one. The cord going to the DC jack has 3 conductors, coax style. I left the center conductor unconnected as it didn't have any voltage on it when probing. Now I just realized that there is the word "sense" silk screened on the PCB next to where that wire connects. Could it be a voltage sense feedback that I need to short to the positive connection on the DC jack?...
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Modify output voltage of a Dell power brick
Hi,
I'd like to modify the voltage of a spare 65W Dell power brick that I have to around 17V (instead of the nominal 19.5V unloaded).
I think that I identified the SMPS controller but it's only a partial part number on the marking. If someone could help me get the full part number and/or datasheet I could handle the rest.
The chip is a SO-8 and the marking is 103AIW on the first line and EK713 on the 2nd.
I still tried a few things without the datasheet. I found a 15 k resistor between Vout and a 2.5V pin on the IC. That looked like part...
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Re: Plasma LG 50PK550 picture blanks only when hung on wall
I'm sorry to revive an old thread but for the benefit of Google, I wanted to post the outcome. It appears that it was indeed what I thought, hanging the TV on the wall had caused stress on the PCBs and an audible noise.
What I did to fix it was somehow impose the same stress to the TV when hung on the wall, unscrew all screws to get the PCBs to be stress-free and then rescrew everything. It worked.
The hardest part was figuring out how to hang the TV from the mounting screws while having access...
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Plasma LG 50PK550 picture blanks only when hung on wall
Hi,
I have a 3 years old LG 50PK550 tv that has an intermittent problem. After usually about 5 minutes, the picture starts to flicker and shortly thereafter, it goes blank. The sound still works however. This has been going on for only a week or two.
Here's a little background info that might or might not help. I hung the TV on a wall this summer. About 1-2 months ago, it started making a buzzing sound, correlated to the amount of white in the image (more white = louder buzzing). I read that applying pressure to the back sometimes solves this, so I squeezed a piece...
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Re: New Members - please post your introductions here
Hi there,
EE here working in scientific instrument design (infrared remote sensing). My plasma TV is failing and searching on the net I found that tom66 has posted one of the best troubleshooting guide that I found. I'm hoping to get help from the knowledgeable people on this forum.
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