Amiga 500 repair question

[ebauman]

Hi. I recently found an Amiga 500 and have been trying to get it running. Does anyone recognize those vertical black lines and know what that means? It asks for the Workbench disk but won't boot if those lines are displayed, and just returns to asking for the disk again. The one time that they didn't appear it booted normally, so it appears that the computer does work. I'm new to the Amiga and have no clue. Thanks.

[ebauman]

It's just a regular A500, Rev 5 motherboard. I don't see any blown caps, but I'm no expert. I tried replacing the Denise chip. It worked normally one time, then went back to displaying the black lines and wouldn't boot. I'm afraid I just blew the replacement chip.

[ebauman]

Hey thanks, that worked! I re-seated the chips one by one and it turned out to be the PAULA chip. It now boots fine.

[ebauman]

But... one more issue. Some of the keys don't work. It's not random, but in vertical columns. For example the number 1 doesn't work or any of the keys beneath it (Q, A Z). Nor does 2, W, S, X. Some columns work fine though, as does the numeric keypad. Does that make sense to anyone?