Windows 10: TPM missing in BIOS after tech reinstalled same motherboard

I have a Dell Inspiron 7373, I use Bitlocker with password
I have the latest BIOS 1.17.0 Aug 2020
Support is going to replace motherboard but the new motherboard did not work so he reinstalled the old one until he receives the new one and schedules another visit - since the reinstall restarts have been requiring the full Bitlocker recovery key, I tried to change the password but it wont let me, TPM is missing
I currently suspended bitlocker, should I just wait for the new motherboard before I troubleshoot this or is their a simple solution?
Note: when I try to resume bitlocker, it says TPM Module is missing
I do not see TPM in security or system in Device Mgr

:)

 

Move Install to New Motherboard, TPM On/Off, and Fresh Start

Thanks for the reply and the links. In the TPM link, it mentions that only TPM 1.2 can only be turned off and only with Windows 10 Builds 1507 or 1511. I double-checked in tpm.msc and in Windows Security > Device Security > Security Processor Details and
there's no option to turn of my TPM 1.2 in the current Windows 10 build (version 1903, build 18362.418). According to that document:

"You can use the Windows Defender Security Center app to clear the TPM as a troubleshooting step, or as a final preparation before a clean installation of a new operating system. Preparing for a clean installation in this way helps ensure that the
new operating system can fully deploy any TPM-based functionality that it includes, such as attestation. However, even if the TPM is not cleared before a new operating system is installed, most TPM functionality will probably work correctly."

So, I thought to just do a Clear TPM from Windows Security instead, but also according to that document, it will just automatically re-initialize itself afterwards:

"Clearing the TPM resets it to an unowned state. After you clear the TPM, the Windows 10 operating system will automatically re-initialize it and take ownership again."

"...

1. You will be prompted to restart the computer. During the restart, you might be prompted by the UEFI to press a button to confirm that you wish to clear the TPM.
   
2. After the PC restarts, your TPM will be automatically prepared for use by Windows 10."
   

So, if I Clear TPM, do I NOT restart the machine on the current motherboard or before doing a Fresh Start/Reset/Reinstall? Or would it be better to just leave the TPM entirely alone since "most TPM functionality will probably work correctly."

Also, do things like Fresh Start, themselves, notice a TPM is present and prompt to do something with it before wiping the current install?

 

TPM

Press Windows key + R

open TPM management by enteringtpm.msc in the Run window.

Hit Enter

In the right-hand pane, click on Clear TPM and wait for Windows to restart automatically.

After restarting, open BIOS settings (UEFI in my case).

Again clear the TPM from the BIOS settings. It may be listed under Security tab.

Save the changes and exit the BIOS.

 

TPM update

Don't know if this is the right place for this thread but whatever, laptop informed me that " a firmware update is needed for you security processor (TPM)," now, i looked up what to do and from a microsoft support thing, the last step says to clear the tpm. it has a warning saying to back up my data, i would like to know what clearing the tpm does, and what measures i need to take to make sure nothing goes wrong.