I received my Apple II Plus today from eBay. I powered up my computer without adding anything into it (it didn’t came with any card either). It started up in the ROM Applesoft BASIC just fine. However, I found one problem on this machine. All modifier keys doesn’t seems to work. For example, I want to enter the quotation mark, it should be shift+2 on this machine, but both shift keys don’t work (2 works, it writes 2 on the screen just as if the Shift isn’t been pressed). Control+G should create a beep, but the control key doesn’t seems to work either as it just enters a G on the screen. The speaker definitely works as the power up sound do work. Reset and esc doesn’t do anything either.
I’m thinking it might be a keyboard problem, but it is weird that it’s only the modifier keys that don’t work though.
Where should I look next?
P.S. the return and repeat key does work on this machine.
Update: I found a switch in the outer side of the Keyboard circuit board labeled S1. After flipping that switch it appears that the reset key started working. Not sure what that do though, might be related to this problem.
Update 2: I forgot to mention that the power LED also doesn't work on this machine. After taking apart the keyboard, I found out that the 3 keys that don't work are on the same wire as well as the power LED, maybe something broke there?