You better remove it and check the pin that disables the safety. You may have done something wrong. The 90T came with a pin to install that disables the safety. Follow the directions on page 11 and also 14 in the owners manual. If you need a manual, PM me with an email addy
The culprit was that previous owner took Loctite and glued the safety selector trip on the trigger pack and it moved just enough not to be able to get the group out so I pried the lever and it came right out there was no pin in the group to disable the safety. I am not sure why you would want to disable it anyway it is a manual safety so just leave it in the fire position and you are good to go always it does not reset it self. So very happy with my new rib and the gun has a really good feel to it now.
Yes, there is a correct procedure for installing the 90-T trigger assembly back into the gun.
The safety button must be in the "OFF" position. In this position, the pin on the safety pawl(the little toggle on the back of the assy), will slip between the legs of the safety button.
If the safety is "ON", the small pin on the safety pawl can slip ahead of the front safety leg, preventing the safety to move to the "OFF" position. Also, because of the position of the safety pawl, the trigger assy will not come out of the receiver.
The safety buttom will need to be removed by accessing it through the back of the receiver. You will need to know how the safety assembles on the inside to remove the button.
If you're unable to disassemble, I'll correct it for you at no charge...you just pay for the shipping.