Over the years I have collected a number of these - eight to be specific. All of them came bundled either with Atari 2600 jr or 7800 consoles.
Recently, I took the time to clean them all up and test them. Since I had a 7800 up and running it was the logical candidate to do so! The Asteroid-game is already installed and it uses all of the buttons on the gamepad.
Lo and behold, 50% of the pads (4 to be specific) had a non-working secondary fire button! At first I thought this must be due to age, but I'm not so sure anymore. Using my multimeter I isolated the problem to pin 5 of the DB9 which has no contact to pin 2 on the fire button-pcb.
This is consistent with all four of the pads. Since my eight pads are in very different conditions - ranging from almost new to pretty worn down - I'm wondering what may be the cause. Especially since two of the ones in very good condition also show this problem!
Pin 5 is on the very left of the db9 female-plug, so maybe there's more pull on this side or the cable breaks more easily when being plugged in and out?
On the other hand, no 2600 game (to my knowledge) uses the secondary fire button, so is it possible, that Atari packaged non-working gamepads with 2600 jr consoles? No way to test and no way to know without a 7800?
Any ideas/theories on this?
(Fact is, the plug must be replaced, else you can't use the gamepad (properly) on a 7800!)