Its A 4 pin jack, It Uses 1,4,5 & 2. East Fix. Part Number 099-0912-000.. Common Problem, They Break All The Time.

This Is A VERY Easy Fix. That Brace You Speak Of Is Also The Heat Sink. 1st.. Remove The Two Screws From The Chassis. Leave The Two One The Circuit Board. 2nd. Pop Off The Two Wires Next To The Fuse (It Doesn't Matter If You Mix Them Up On Reassembly). 3rd. Pull Off ALL The Pot. Knobs. & Remove The Nuts. 4th. Remove The Two1/4" Jack Nuts. 5th. remove The Philips Screw From The Aux. In. The Chassis Will Now Slide Out Enough For Servicing. Reverse Procedures To Re Assemble.