Dell Optiplex 5050 SFF - strange behavior and service_mode jumper not working anymore

[MMH3]

Hello,

i have many 5050sff. all of them, and how i experienced over many years for all about 250 DELLs goin through my hands, are fully flashable and can be serviced in any way when the service_mode jumper is set.
Never ever i experienced problems with that.

Now i have one 5050sff machine, where this jumper isnt working at all.
I do not get the normal messge that the jumper is set when booting and a short test with FPT just confirms this. Everything is locked -->> EVEN for reading !?

The history of the machine is that i used it in my office many years, so, as for all "my" machines I did 100% documentation and a chip-off backup of the whole SPI.

Then the machine was sold used and came back one week later as "faulty" with the fan running all the time as soon it is shutdown and the power LED went off.

Now at a closer look, I am finding that this .. lovely.. customer messed around with the bios getting TPM 2.0 for Windows 11 can be installed. Originally there is TPM 1.2

This customer oviously even changed the Bios-Chip from the original Macronix to some GigaDevice type !! As a see comparing it to my documentation of this machine-servicetag

So, knowing all the problems could be a "ME=not clean" or Bios corrupt Isssue, i already took out the chip replaced it with a new one of the original type and reflashed it via programmer with the 100% original working SPI backup mentioned before.
Hoping this will restore 100% the previous working state.

But this does not change the fan problem.

Instead now i have two more additonal issues

1.)
the machine alerts every boot that the TPM module can not be found !? An now every option for this TPM completely dissapeared in the Bios
(the alarm i got "under control" downgrading the bios as far as possible with the normal F12 dell option, but still not any option for TPM in the Bios)

2.) .. most strange...
the service_mode jumper is not working in any way

Anybody have an idea what is wrong with this machine?
Is there a additional hardware for TPM the "customer" took out and i´ve overseen this?

Find the full boardnumbers in the screenshot attached and the SPI backup (Bios-Ver. 1.20) which was working 100%

Servicetag: 91QSZL2
Servicecode: 19696529702
Board-serial: /91QSZL2/CNFCW0078N02UH
MAC: D8-9E-F3-14-66-B8

Any help is appreciated.

[MMH3]

ok, i have to admit myself being a little bit stupid.
the "service_mode jumper" problem i was able to solve myself .. replacing the CMOS-Battery..

but what is left are the two problems with the TPM-Modul missing alert in all Bios Versions greater than 1.4 and the CPU-fan spinning up at full speed as soon as the machine is fully shut down.
also i forgot to mention that the fan and the PSU was already exchanged for test with known good ones. both good units result in the same behavior of the fan.
also the perboot diagnostics are testing the fan-behavior audible as 100% normal.

as i not know wether i did something wrong i also upload the SPI Bios Version 1.20 again
as mentioned before this was 100% working previous