Well, the issue can be caused by various reasons. Broken ribbon cable, broken LCD, bad BIOS, etc. Connect it to an external monitor and try again.

dominusprog wrote on 2024-07-13, 23:32:

Well, the issue can be caused by various reasons. Broken ribbon cable, broken LCD, bad BIOS, etc. Connect it to an external monitor and try again.

I connected it to an external monitor but the monitor display was still blank and didn't seem to recognize a device was connected.

Open it up, there's a NiMH battery in I think the palm-rest area somewhere around where the memory card plugs in. It's probably corrosion / damage to some traces, my 4000C is non-operational from the same thing

Try to replace memory or HDD, this can be issue too. I have 4000C and it works fine.

Thermalwrong wrote on 2024-07-14, 00:57:

Open it up, there's a NiMH battery in I think the palm-rest area somewhere around where the memory card plugs in. It's probably corrosion / damage to some traces, my 4000C is non-operational from the same thing

I flipped it over too look at the battery contacts and it seems to be fine. Or are you suggesting disassembling the entire notebook down to the board and looking there for signs of damage?

MAZter wrote on 2024-07-15, 14:25:

Try to replace memory or HDD, this can be issue too. I have 4000C and it works fine.

I have a CMOS battery on the way to me now, could that solve this issue? Didn't think that HDD or memory could cause a no-boot situation. I have a CF to IDE adapter but it seems this NEC 4050c has a proprietary HDD connection. Do you think these adapter/connectors on ebay are the right kind?
https://www.ebay.com/itm/184216746184

https://www.ebay.com/itm/110890417176

Does anyone know how to connect to this type of hard disk connection? Is there an adapter?

Or are there any other suggestions for getting this notebook to boot?

I've disassembled the 4050c is there anything here that should be inspected or replaced? Looks pretty clean to me.

I don't know how to disassemble further than this. There is at least a better look at the backside of the weird HDD connection. Does this make it easier to identify a way to connect to it?

footnmouth wrote on 2024-07-20, 21:50:

I don't know how to disassemble further than this. There is at least a better look at the backside of the weird HDD connection. Does this make it easier to identify a way to connect to it?

Huh, your one looks way nicer condition than mine was.

Remove that green battery and don't reconnect / replace it, it only powers the RAM in standby mode and isn't important. Then check the opposite side of where that battery hooks up since it's got some important memory lines running through it, look for anything green and crusty which would indicate that green (NiMH) standby battery has leaked. If there is any, clean it off with some isopropyl alcohol (IPA) and a stiff brush.

Try re-seating that top PCB with the CPU on it since a bad connection on the board-to-board connectors will also stop the computer from working. You can try spraying some IPA or contact cleaner into the connector and push it back in a couple of times to make sure it's clean.

Hopefully it'll just be that that's stopping your 4050C from working 😀

Have you tried connecting the laptop up to a VGA display to see if it outputs to that? It could even be something basic like the internal display's backlight not working

Thermalwrong wrote on 2024-07-20, 23:12:

footnmouth wrote on 2024-07-20, 21:50:

I don't know how to disassemble further than this. There is at least a better look at the backside of the weird HDD connection. Does this make it easier to identify a way to connect to it?

Hopefully it'll just be that that's stopping your 4050C from working 😀

Have you tried connecting the laptop up to a VGA display to see if it outputs to that? It could even be something basic like the internal display's backlight not working

Disconnected green standby battery. No corrosion. Reseated the cpu board and reassembled. Hooked it up to a monitor and it still does not boot same as before.
The monitor doesn't even recognize that a device is connected via VGA when I turn the 4050c on.

Managed to find and overpay for an untested OEM NEC 810Mb HDD+caddy. Hopefully when it arrives it'll work and magically allow this 4050c to boot.