Neo Geo CD P1 START button not working

[Demiurgo]

Something strange happens on my top loader. Console does not start any game, it keeps on the CD menu, and I am able to play CD tracks, but to start the game I must press START button, as a message indicates, and this is not working.

I can move by the menu, so the directions and selection buttons work, but not the START one. This only happens with the pad on the P1 socket. If I use it on the P2, the game runs flawlessly after pressing START button.

I tried a pad and a controller, both from SNK, and neither work on P1, but they do in P2. I checked continuity of the START pin on the P1 socket to a resistor array, so is working until there.

Any idea to fix this?

 

[egg_sanwich]

Perhaps try cleaning the controller port on the console? A q tip dipped in isopropyl should do it.

 

[Demiurgo]

Thanks for the advice. Tried it, but no changes.

 

[GadgetUK]

Something strange happens on my top loader. Console does not start any game, it keeps on the CD menu, and I am able to play CD tracks, but to start the game I must press START button, as a message indicates, and this is not working.

I can move by the menu, so the directions and selection buttons work, but not the START one. This only happens with the pad on the P1 socket. If I use it on the P2, the game runs flawlessly after pressing START button.

I tried a pad and a controller, both from SNK, and neither work on P1, but they do in P2. I checked continuity of the START pin on the P1 socket to a resistor array, so is working until there.

Any idea to fix this?

The most common cause is the pins on the joystick ports being pushed too hard and the pin for start has probably cracked off the PCB inside. I've seen this happen on a few ports on the Neo CD. If it's not that, it could be a problem with the neo buff chips on the Neo CD controller PCB, the ribbon between the controller input board and the main board, or one of the 74HC245's on the motherboard - but that's quite unlikely I think.

You can see the two videos I did covering the exact same problem here:-

Part 1 https://www.youtube.com/watch?v=E81QVouw2yo (see around 8:17 - EDIT: And also see around that part of the video how they can sometimes get pushed inwards)
Part 2 https://www.youtube.com/watch?v=GfXWMFMM7TY

 

[Xian Xi]

Haven't really looked at a NGCD but if it's like the other systems then it could just be a bad resistor pack.

 

[Demiurgo]

Thank you both!

As a last resort, I was about to replace the resistor arrays, following Xian Xi´s comment, and even the capacitor, but first I was following the extensive videos from GadgetUK. I was using my logic probe after feeding the board with 5V when I checked again continuity for the P1 START button... and it was gone. Using a magnifying lens, I saw a crack just where the trace joins the soldered pin. My guess is the crack was there before, but was only cutting the trace when a controller is inserted, this is why I was able to confirm continuity when I tried first. Probably the crack widened when I inserted the controller with the board removed from the console.

Anyway, I used a wire to join the START pin with the appropriate one in the resistor array, returned the board to the console, plugged everything, and... IT WORKS!