I have an old "Adjust-a-Volt" variac. Shortly after I bought it, it started smoking and now the windings look burned for about 2 inches around the left side. Is it possible to fix this or bypass the shorted windings? I'm not sure how to detect where the bad windings are, except by appearance.
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Pictures?
Usually smoking windings are indeed a place to look for shorts. Might be easier to clean and restuff with some epoxy or varnish so that it's not shorted anymore if the winding is still intact, winding is so tight on there that putting a jumper still requires you to cut the bad section out. -
So you mean just cover the windings with, for example, polyurethane from the hardware store? Here's a photo of the windings (on the right)
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woah wtf.
that tap is the input/hot tap, the browned out section is the "boost" section and the right is the 'buck' section?
Usually if you have a short, two adjacent windings are shorted. This looks like you have a whole bunch of windings that are overheating? Means the boost output is shorted against something perhaps?Comment
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Umm… what did you do to this variac? Must have drawn some current all right… does the variac still work?Comment
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I have no idea what caused this. I just plugged it in one day and it started to smoke.Comment
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You got something that will measure AC current like an energy monitor? It probably doesn’t adjust the output anymore properly either? I am a bit surprised that it doesn’t blow a fuse.Comment
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make sure the output isn't shorted and you're not chasing after something that doesn't exist...Comment
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Hello:
I have both these laptops that appeared to have the same fault so I thought I would have a go at replacing the PCH as something to learn, they both are using the same PCH.
I started on the ACER:
Up on connecting power no signs of life but current is consumed from the bench power supply and the PCH is hot.
All the caps on the top of the PCH are showing 0 ohms and the 3.3v rail is shorted.
I followed the videos from Sorin, Electronics Repair School on Youtube heating from the bottom to install. I practised on around 10 scrap... -
Hi every one. I just want to share the successful repair of my shorted Panasonic TNPA4782AB SC board.
I don't usually do it but so many parts were shorted that I decided to buy the ShopJimmy repair kit instead of sourcing each components individually. Here is the list of components the kit contained, with a remark indicating if I needed that part or not :
D608, good
D618 RF101L4S, good (See warning 1 below)
D619 RF101L4S, good (See warning 1 below)
D865 RF101L4S, shorted (See warning 1 below)
IC464 Inverter HA MC74HC1G14, shorted...03-09-2020, 12:00 AM -
Hi to all,
the owner of this machine gave it to me after having opened it to take off the dust from the inside, telling me that after that it didn't start anymore.
I found that one of the DrMOS (AOZ5016QI) on the CPUCORE was shorted between VIN and VSWH, and that one of the two n-mos connected to the power jack was shorted aswell.
I unsoldered the two shorted components and verified that there were no other short circuits, then decided to power the mainboard, firstly with the lab power supply, then with its original HP 200w charger, but the behaviour is the same, the board starts... -
Hi,
today I got Razer Blade 14, Ryzen 9 6900HX and RTX 3070Ti.
Laptop was completely dead. I found shorted CPU VRM mosfet, shorted 19V mosfet and blown battery fuse.
I replaced it all, but still on CPU coil where mosfet was shorted I got very low resistance, near 0 ohms. On other CPU coils I got around 3 ohms.
Laptop now raises voltage on whole board, but still nothing comes on the screen. CPU gets 0.7V on all coils except the shorted one. CPU gets only slightly hot, below 40 C.
I removed coil and injected 0.7V, it draw around...09-27-2024, 12:44 PM -
Hello,
This is my problem:
Laptop: Dell Latitude 5501
Motherboard: EDC51 LA-H181P
I have two power rails shorted to ground, +1.0V_PRIM and +3.3V_ALW_PCH. I removed solder on PJP302, +1.05VALWP (pad1) not shorted but +1.0V_PRIM (pad2) shorted.
I also cleaned PJP38, pad1 not shorted, pad2 (+3.3V_ALW_PCH) shorted to ground.
I measure the resistance of all the coils on the motherboard and they all were not shorted to ground except coil PL301 before I removed the solder on PJP302.
I injected +1.05V - 2A...
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