Can I reset tv to original factory setting without remote

If both your front panel and remote control are disabled, the best option would be to perform a factory reset to restore the TV to its original settings.
To reset the Sharp LC-40LE830U to factory settings:

1. Unplug the TV from the power outlet and wait for at least 60 seconds.
2. Press and hold the power button on the TV for 5 seconds while the TV is still unplugged.
3. Plug the TV back in and turn it on using the power button on the TV itself.
4. Once the TV is turned on, press and hold the "input" and "volume down" buttons on the TV simultaneously for 5 seconds.
5. The TV will then enter the service mode menu.
6. Press the "menu" button on the remote control to navigate through the menu and select "option."
7. Select "factory reset" from the options menu and follow the on-screen instructions to complete the reset.

Note: The factory reset will erase all custom settings, including parental controls, picture, and audio settings.

This model set uses 3 different main boards, they all look the same but not interchangable, this sounds like you have the wrong part installed. Match the old board part number to the new one, I think you will find they're different. If they're the same you received a defective board

You need a remote to do the more complex features. It depends on the buttons available in the set and the options in the menu. A replacement remote doesn't appear to be available.

https://www.manualslib.com/products/Aiwa-Tv-Sa2151-3673574.html

https://www.google.com/search?rlz=1C1QJDB_enCA643CA644&sxsrf=ALeKk03zeYGgdN6tCNDl3ZXJ7R0UgzdLOw:1628180934769&q=aiwa+%22sa2151%22+remote+replacement

I think it is time for a new set by the sounds of it!
..

Do a factory reset. There are two methods to reset TVs. Hard reset and factory reset. To make it a hard reset unplug the set from the AC mains wall socket and reinsert after an hour or so. To make a factory reset you have to enter it's service mode option. If you wish to get more details visit the site linked here. http://electronicshelponline.blogspot.com/ http://homenol.blogspot.com/

To reset it to its factory settings, you must have its original remote control. A universal remote won't go.

Without its remote control, you can't do a system reset to this set.
Try a Hard Reset to this set, and then check.
There are two methods to reset TVs. The first is simple to do; a Hard Reset. The other is somewhat skilled; is a Factory Reset (System Reset). To make it a hard reset, just unplug the TV from AC mains wall socket, and re-plug it back after 15 minutes or so. If you do this by overnight is better. This procedure will make it a hard reset. If you want to make it a system reset [Factory Reset]; you have to enter its service mode option, and select the factory reset option. If you wish to get some details; check the site linked here. Pull up older posts.
https://electronicshelponline.blogspot.com/
Service mode entry, adjust and exit procedure to many popular brand TVs are given. Never forget to exit the service mode, after all adjustments have been done.
If a hard reset do not help, you should buy its original remote control from its authorized service center.

You must have its original remote control do do a factory reset, because, there is no other way to enter its service mode, without its original remote control. A universal remote won't do.

Tries 1-800-Factory remotes originals Website.
U get same as the original remote.

Hi,

Without the original remote, sorry none. You could try pressing on any of the buttons or a combination while plugging in the unit but that is no guarantee it will reset (fully). With your indulgence, I took the liberty of checking your other posts here and here. It would seem that your original concern is that although the TV would appear to be switching to the lower channels (Ch 2-6), the TV programs on those channels would not be displayed. If yes, then I am inclined to think that there is a hardware fault internal to the TV. This would be the tuner block. The reset, even if successful, would not correct this error.

Just a start, do postback how things turned up or should you need additional information. Good luck and Thank you for using FixYa.

Basically all it takes to restore the TV to factory setting is to unplug the TV from power and all connecting cables for about 3-5 hours (depending upon your model). This is called a Hard Reset and should restore the TV back to factory defaults.