I would start with the flipper button for obvious reasons. (test menu)

Does the right flipper work in game normally?

If not I would check for contact of button to blades and insure blades make contact.
Make sure all wires are on solid and no crappy solder job or breaks are present.
It could be an open in the wire between flipper and backbox.
It could also be driver transistor. Check your manual and or ipdb.org for virtual manual.

The left "slingshot" or kicker rubber: you can leave the machine off. take the glass off. Get down close and physically press on the rubber slowly with your hand. Do the contact points touch on both blades sticking out of the playfield? If not you can tweak them and get them touching just after you start depressing the rubber. Give a little bit of room or they will be hyper sensitive.

I have never had the pyramid apart so I am no help there without looking things up to give you ideas.

On the Glider issue, I believe I had the same problem. As I recall there is a fuse bank on the underneath side of the playfield. One of those fuse was blown. I replaced it and the glider worked fine. Good luck.

Hello. Just got a Stargate myself and have a similar problem to your left kicking rubber. My center and right kicker targets don't work during the game, but test fine during a solenoid test, and the switch test shows them as constantly closed. I looked and none of them were closed. I did realize target kicker switch does work because it resets the drop targets when struck (but no kicking or scoring). So I called the pinball resource, inquiring if the switches were available (thinking short). He said it didn't sound like a switch problem to him (six switches -two inoperative and four stuck closed- failed the game's test) and to check the switch matrix. He said the computer remembers that the switch closed but nothing is telling it that it has opened back up so any further input is ignored by the system. In short, check the switch matrix column where the switch appears (pg 50-51 in the manual) for loose wires (both before and after the switch in question). Also check if the other switches (glider forward - left return rollover - left kicking rubber) are in the same matrix. If so, one fix to the faulty part of the matrix may help restore function to them all. I will get to work on mine later and will let you know if I find anything that can help.

Got back late last night but checked the switch matrix diagram. It looks like left kicking rubber, right flipper, pyramid end of stroke, and left return rollover are all in the same matrix. Seems too coincidental. I'd scour that matrix if i were you. Check the diagram column three beginning with #3 coin chute and work down from there. Good Luck

On mine, I replaced the transistor Q3 and cap C16 (? I think that was it - it was the cap in circuit with Q3), also had to replace the coil (was toast) and the 1.5A SB 3AG fuse. Just about everything relating to it.

I used IRL-540 for Q3, and a 0.01 mfd cap for C16.