Dell Precision m6800 won't recognize any power supply (through own DC jack as well as docking port), and battery will not charge

Question

My m6800 has complained occasionally about the AC adapter being seated poorly since I bought it, and I have always been able to pacify it. Since last night, I cannot. BIOS tells me that I have connected a 1w power supply, and the battery will not charge at all.

I tried plugging multiple adapters into its DC jack as well as the jack on a connected docking port with no change.

Dell's support tools show no issues aside from the battery being old. BIOS shows battery health at 39%. I'm unable to check the AC adapter's wattage in BIOS without the battery inserted. Could I just need a new battery?

I disassembled the machine and examined the DC jack on the inside. There isn't anything apparently wrong with it. Could this part be the root of the issue, even though the problem persists with the docking port?

Lightning struck my house late last week, but the machine is surge protected. We lost a couple routers, a switch, and a land line phone.

My first concern was CPU throttling that occurred whenever I connected an adapter, but that stopped after disabling Intel SpeedStep in the BIOS.

The battery still will not charge. I usually use it on AC, but it's nice to be able to transport it between locations without waiting for hibernation to finish first. Is there any way to force the machine to charge the battery?

Edit: This issue is throttling my GPU as well, and I'm unsure of how to deal with that. GPU-Z has it clocked at 160/770 MHz. It jumped up to maximum when I switched to battery for a minute. The battery drained to 6% in about 3 minutes.

Answer 1

I found a solution, but not the answer I wanted: board replacement. After replacing the main board and nothing else, the machine runs at least as well as it did before.

If anyone else has this issue and is hoping Dell will give them a way to disable the throttling feature, they will not, nor are there any schematics that I could find in order to replace just the faulty chip(s).

Final diagnosis: AC adapter not recognized due to a fault in the motherboard caused by an electrical surge through the ethernet port.