A500 rev.5 game port issue

[Jurtappen]

Hi,
All new to this board and I can't find the exact issue I am looking for.

Stumbled across an A500 rev.5 in the attic from my early age of gaming.
It fired up with no fuzz, except the gameport 2 issue.
The upward direction will not work in port 2. All good in port 1. Even the tank mouse works in port 1
Tried several joysticks. Also tested them all in a joystick tester I got from ebay.
Any clues where to begin?

[DownshiftDX]

Check the 74LS157 multiplexer (U15?) near the gameport. I had a similar issue on one of my A500s several years back and I tracked it down to that chip. Once I removed it, put in a socket, and replaced it everything was okay again.

[Jurtappen]

Thanks, I'll see if I can find it. I'm not a trained technician, but is there an easy way to find out if it has a defect? I have both a soldering iron and a measuring device 

[F0LLETT]

Thanks, I'll see if I can find it. I'm not a trained technician, but is there an easy way to find out if it has a defect? I have both a soldering iron and a measuring device 

Download the schematic and use meter to check track (and components) going to port from chips.

I had one with issues in past, turned out to be pin snaped inside port 2 socket.

On side note, you have tried reseating all chips? you can get some really wierd issues with dirty contacts.

[DownshiftDX]

Download the schematic and use meter to check track (and components) going to port from chips.

I had one with issues in past, turned out to be pin snaped inside port 2 socket.

On side note, you have tried reseating all chips? you can get some really wierd issues with dirty contacts.

I did mine in 2017. I was trying it blind based on reading I had done at the time somewhere on some old cached Amiga forums talking about the same problem. I'd already confirmed there was nothing wrong with continuity from the pins on the port to the chip. I didn't have a scope at the time to look at the outputs (not sure I would be able to make proper sense of it anyhow) so I just went for it as I was confident enough if my soldering skill to get the chip out without lifting anything and installing a socket.

[Jurtappen]

Thanks for the feedback. It helps to get some input. Have now removed all chip's that sit in a socket. Even CPU and Fat Agnus. Going to do like "DownshiftDX", order a new IC (multiplexer) and socket for this. Without having tested with a measuring device first. At the same time, I am waiting for two new 9-pin game port connectors that I will also change.

[Jurtappen]

Replaced the IC and it went from bad to worse🙈 Fire button works, but when I try joystick left side it goes left and one step up. Same thing when trying right side, it goes right and one step down. Up and down doesnt respond at all now😁 (tested in Lotus espirit turbo II menu). Also tried to turn the IC the other way around but then the Amiga wouldnt start at all.