I have a mainboard that constantly draws 250 mA. The cooler is getting warm. How can I tell the difference between a running and a shorted CPU?
How to distinguish a looping CPU from a shorted CPU?
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by reessiHello:
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... -
by YanlebHi 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 -
by modtoolHi 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... -
by BalkanBoyHi,
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 -
by barry101Hi, Would appreciate some help.
I have an Apple Late 2013 15" A1398 MacBook Pro with Logic Board 820-3662.
Get charger light but no fan spin or chime. No liquid damage.
Found PPBUS and VCORE both shorted to ground. Other rails were ok.
Removed VCORE MOSFETS U7310, U7320 and U7330. Found U7330 was in fact shorted.
With the 3 MOSFETS removed, get PPBUS and fan spin. VCORE is still hard shorted to ground (0 ohms).
Attempted voltage insertion on VCORE to locate short using bench supply set at 1.0 VDC and 4.95 Amps (max current for my... - Loading...
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