Yes you need the 90w one which is probablywhy the 65w put the lights on but no one was home.
Also confirmed here
HP Pavilion dv7-6c54ea Entertainment Notebook PC Product Specifications | HP® Customer Support
There are several different models of DV7 all with differing PSU specs. The 120Watt one is for the model with 17 inch screen and ATI Radeon GPU. Lesser spec models have a 65Watt PSU, so, it's important to get the right one. There are also variants of CPU to consider as well, so I would check the exact specs of your model and order the correctly "sized" PSU for your specific model.
That's what the previous post did with the exact model number ...
I'm not convinced to be honest. The laptop has a battery in it - it should power on regardless as to whether or not the connected power supply is adequate. It should also charge if left turned off with the smaller PSU connected.
Only if the machine is running flat out with the dedicated GPU running will the battery gradually discharge whilst in use.
I can't see how an inadequate power supply can be causing the symptoms the OP is describing (lights on, HDD spinning up, but no video).
Ah... yours has in i5 CPU and AMD Radeon GPU and needs a 90W PSU......
He has no battery (a dead one)....
Thanks for confirming. 90w on the way.
Just out of interest as you guys have been so helpful maybe you can help identify which charger I would need for small Medion SIM2090 Notebook? Nothing we have fits in the AC hole as the barrel is smaller. Pic attached.
Amazon has replacement if you search for that particular charger model number
Okay it's 90 Watt version due to the two gpu's
https://www.amazon.co.uk/CYD-PowerFast-Replacement-Laptop-Charger-Elitebook/dp/B07M9TD3J6/ref=sr_1_1?keywords=hp dv7 90 watt adapter&qid=1562690877&s=gateway&sr=8-1
Better price
90W Adapter Charger for HP Pavilion DV5 DV6 DV7 CQ35 CQ40 Laptop Power Supply UK 611745774479 | eBay
But as I said at least with Amazon you can return it if laptop if you no longer need it due to the lappy not working.
Here you go
https://www.amazon.co.uk/Wikiparts-ELECTRONICS-ADAPTER-SIM2090-ADAPTOR/dp/B00DGVS93K
Genuine DELTA MEDION SIM2090 Laptop 65W AC Adapter Charger Power Supply New| eBay