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.

[Boing-ball]

That’s not normal. Looks like you have something failing on the mainboard. You mention A500. Is it a A500 or a A500+ ? If the latter, they had Varta Batteries that would leak out battery acid whic in time causes trace failures and green gunk.

[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.

[F0LLETT]

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.

I never see any A500 faulty, only even seen dodgy connections. Try reseating all chips.
I see really wierd stuff, if the CPU connections are poor.

[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?

[Boing-ball]

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?

That sounds like the Keyboard membrane. Might need to buy a replacement.

[hd74ami]

The keyboard membrane traces might be possible to repair with silver glue, but it's difficult. You can use a multimeter to measure the resistance between the membrane pads and the connector to the little circuit board on the keyboard frame.

[Boing-ball]

The only other thing I can think of, is the Graphite of the key plunger maybe failing. You can clean these by rubbing a bit of plain paper. Either all, it will mean keyboard disassembly.

[F0LLETT]

The keyboard membrane traces might be possible to repair with silver glue, but it's difficult. You can use a multimeter to measure the resistance between the membrane pads and the connector to the little circuit board on the keyboard frame.

The keyboard membrane traces might be possible to repair with silver glue, but it's difficult. You can use a multimeter to measure the resistance between the membrane pads and the connector to the little circuit board on the keyboard frame.

Your forgetting something. This is an A500. Completely different to A600 / A1200. Keyboard chip is on keyboard. So its more than likely an issue there, as apposed to membrane itself.