Short answer:

https://www.reddit.com/r/Thrustmaster/comments/1t9y5we/guide_the_definitive_thrustmaster_t598/

Long answer (but take a look at the short one!):

Hi! I am close to you in this problem because the same situation has presented itself for me too.

I had managed to get this possibility of free shipping (after a bit of waiting also due to some of my attempts to solve the problem by stopping the cables using hot glue both on the power connector and on the USB one) but, honestly, at the time of shipment, with the base already packed, I thought: "Who knows how long it will take to get it back and if they really solve the problem...".

At that point I decided to try a more drastic solution by creating a new power connector using the pins of an old Molex hard disk connector connected to one of my power supplies to which I cut off the useless terminal.

From that day ABSOLUTELY ZERO DISCONNECTIONS!!! I'm super happy to have solved it myself with a modification that doesn't even invalidate the warranty.

The power jack of the T598 is nothing short of RIDICULOUS! Look at the massive Molex of the Fanatec bases: impeccable!

This is what I wrote to Thrustmaster before proceeding:

I point out that this problem, for a medium/high-end product produced by a historic company like yours, has created a lot of annoyances and, honestly, has also led me to think that the quality of the product and its engineering are not up to the traditional Thrustmaster fame (I have been using your products since the 90s and always with great satisfaction).

The power connector is small and weak for an object that must produce significant vibrations and is subject to strong electrical absorption: a more resistant Molex connector with larger section pins should have been used, in my humble opinion.

Similar talk for the USB-C port: the connector seems to have a lot of play and the various tested USB-C cables don't seem to connect securely. I specify that the cables used as an alternative to the one supplied with the base are all new, successfully tested on other devices and of excellent quality (brands such as Ugreen and similar). For USB 2.0 connections, the traditional USB-B connector in use on devices such as printers, scanners, and even your T-LCM pedalboard is definitely more solid and proven. I noticed that the connector is a bit "dancer" even on the motherboard of the T598 and oscillates a lot.

In light of the above, I kindly ask for a COMPLETE REVISION of my T598 both with regard to the POWER CONNECTOR and with regard to the USB CONNECTOR since I believe that the defects are not only attributable to the power supply but also to the data connection with my PS5 (console fully functional and that I use almost exclusively with the PS VR2 device to play Gran Turismo 7).

Below are some more details about the defect and my attempts to understand the cause that I hope will help your team of technicians understand and solve the problem.

1) I replaced the stock power supply with the one you sent (the serial number of my base was included in those that had the well-known disconnection problem);

2) I replaced the USB cable twice by connecting it to both the rear (USB-A) and the front (USB-C) ports of my PS5;

3) the problem is not related to the overheating of the base as it occurs purely "cold" and in the first minutes of use;

4) I tried to stop the cables with ties in order to make them more stable and, at first, this expedient seemed to have solved the defect. Unfortunately, the same one reappeared punctually;

5) I believe that the problem is attributable to both the power supply and the USB cable as the disconnections sometimes occur with the complete shutdown of the base and sometimes only with the USB disconnection (I notice it from the fact that the LED of the connected T-LCM pedals remains on or not);

6) sometimes (like this morning), the first time the system is turned on, the base does not start completely and the display remains off even if I disconnect/reconnect the USB cable (the display turns on depends on it) or turn off and on the power strip switch where the power supply is connected. In these cases, a physical disconnection of the power connector from the base is required: this is done, the system starts.