On the bench it's 100k ohms, but on the board it's 0 ohms.
-
Please check on both sides of the 100k ohm resistor on the logic board. No power to the imac. Maybe you are measuring the 100k ohm resistor leg that is going to ground? -
both side are 0 ohmComment
-
Carefully flux and remove this part off the board. Then check the resistance to ground on the pcb pads only on the logic board ( no resistor ). The fault may be a solder blob across the pcb pads.Comment
-
Hi guys, i was wondering, i've got 9Ohms on Vmem, one of the mosfet was shortet to ground, so i've desoldered hi and low mosfets nad still low res, then i removed all of the memory chips, and the resistance is still low, so did you had maybe a card with that low res on memories, and the card was working fine ?
Removed the U1866Q and still without result, i dont have thermal cam so can't see where is hot spot when incjeting voltage.
The resistance on core is ok 0.1Ohm ((Power 0.8V when on)
Resistance on 12V 4K ohms (Power present when on)
Resistance on 12V PEX 4K ohms... -
Hi, I'm Daniel, and I'm new to the world of repairing motherboards.
I would like to create a table, or more likely a guideline about the voltage rails and their possible resistance rail.
I know that the motherboard design has a very big depend on the rail's resistance, but I would like to know what is the smallest value for a rail that can be acceptable. For example, I heard that some new gaming motherboards can have 0,5 Ohm resistance on the GPU rail, but on an older type, it could be a sign of a shorted GPU rail.
So, I generated a table with AI so I can... -
Hi guys, I need your help again.
I have this iMac from a customer that shut down during a storm along with all the other devices in the house. In particular, the router, connected via Ethernet to the iMac, caught fire.
When I removed the screen from the iMac to check the status of the LEDs, I noticed that none of them were lit. I had a perfectly compatible and working power supply, so I tried it right away, but the problem remained the same (no LEDs). With the thermal camera, I noticed only a slight warming (32 degrees) of the NCP1605BG chip on the power supply. The rest was completely... -
iMac turns on no drops no cracks, tried to DFU Restore the iMac, logo turns on great! however iMac turns itself off and then restarts to the (!) icon and won't post the restore. Tried thunderbolt 3 cable, tried regular USB C cable and nothing.
this is the message it gives me with the error
Unexpected device state 'DFU' expected 'RestoreOS' (Probably forced into DFU mode externally) [com.apple.MobileDevice.MobileRestore – 0xFAE (4014)].
Any thoughts what this could be? I will open it up and repair it but I am not 100% sure since this iMac doesn't... -
Customer came in for data recovery, came to find out data is soldered on to this iMac (learn something new everyday) this is a 2020 T2 iMac so I was surprised because the iMac Pro has a T2 chip and it isn’t soldered on. Anyways, the iMac boots to Apple logo and then restarts, before it turns off you hear a quarter fan spin then it repeats itself. I decided to do a DFU revive to restore any hardware firmware issues and it was successful in reviving the device however the issue persists in boot looping. It shows the Apple logo for like 40 seconds then turns off and fan spin rinse repeat. I...
Comment