Thanks for all the replies, Peva.
I looked far and wide at all the boneyards and came up with nothing. 99.9% of the Intrepids that had an MTC display still had them in the cars. 100% of the Treps that had ATC displays had them already taken from the cars. Very discouraging.
So, last night I decided to head up to my neighborhood Radio Shack and see if they had a 47uF capacitor to replace the one I accidentally broke off the PCB board. It's just a little can-type, aluminum electrolytic. They had one, but it was the "radial" style. The diameter was about the same, but it was about 3 times taller than the SMD type I broke off. $1.49 +tax. Probably $0.33 from Mouser but more $$$ to ship it. No big deal. Nothing to lose so I bought it. Wasn't sure the increased "tallness" of the new capacitor would "clear" the plastic cover when I put that back on.
Went home and soldered it on the board. I put the leads of the new capacitor through the small, plastic base that was part of the old SMD cap I broke off. Soldered it in. Went out to the garage, plugged the ATC back in and turned the key on. Display lit right up. Pressed all of the buttons and all seemed to be working EXCEPT I didn't have a blower. Then I remembered I had removed the 30amp fuse to shut down the unbearable heat from the heater blowing full blast without the ATC hooked up. Replaced the fuse and it seems to be working. I left it on for about half an hour. I will recheck today before putting everything back together.
Yeah, the only thing I really did to the board was resolder the resistors at R14, R20, and R21. I also re-soldered the 3 prongs of the voltage regulator and the leads of the power plug-in. I could see the hairline cracks between the resistors and the solder with my 10X magnifying headset. It didn't seem like that was enough to cause all those problems, but apparently it is.
Diagrams for this kind of stuff are nice because they usually give you more specific information about the components on the board such as tolerances and voltages, etc. No big deal, though. It seems to have worked out.
The "1Q" is MORE than on the wrong side of the board. I figured out it was an identification for the voltage regulator on the other side. Look at it. The "1" is backwards and the "Q" is backwards. Like how you would see it in a mirror. At least on my board it is. Weird.
So, hopefully, this will wrap this one up. It's been acting up for quite a while. Way over a year. I could tap on the side of the dash and get it to light up and that's what I've been doing until it wouldn't light up anymore.
I have another minor electrical issue, but I'll start a new thread. First, I'll do a search and see if it has already been talked about, which it more than likely has. "Sometimes", when I pull into park the car, and I'm moving the shifter from Drive to Park, BOTH traction control lights (Traction Control ON and Traction Control OFF) will light up in the dash display for about 5 seconds and then go out. I have my foot on the brake at the same time while shifting from Drive To Park (obviously), so it seems whatever is going on is somehow related to that sequence. The display is only on for a few seconds and then goes out. It seems to be minor. I know both Traction Control ON and OFF lights shouldn't be lighting at the same time except when I first start the car and the computer runs its checks. It's a project for another day.
Thanks for all the help, Peva, and everyone else who added their input. I appreciate it. I do still stand by what I previously posted above in that the next car I buy is going to be a much more simplified vehicle without all the bells and whistles. Hand crank windows, manual heater controls, no power seats (I have set my seat one time since buying the car and never moved it), etc. The more "crap" on a car, the more things to go wrong and the more costly it is to fix it.
Thanks again all.