[Electronics] Sega Megadrive controller - D pad 'up' not working.

[Jimbo Mahoney]

Retro one for you electronics guys:

The 'Up' doesn't work on a Sega Megadrive controller I have.

I've taken it apart and tested as best I can with a multimeter - the contacts are clean, as is the rubber button contact. The cables are fine and the voltages are all good.

The only difference I can detect with a multimeter is a resistor - the three resistors that do Down, Left and Right are all 9.9 kOhms, the one that does Up is 9.7 kOhms - is this enough of a difference to cause it to not register a button press?

 

[Apopcalyptic]

Couldn't tell you I'm afraid, but I've got several spares if you want one!

 

[JaFFa]

it will be a lot easier to go to a second hand shop and get another one.

 

[Chaos]

I think the megadrive controller is all digital and uses the 157 chip shown in this pdf -

http://www.ti.com/lit/gpn/cd74hc157

I think pin 1 is joypad up according to a book I have.

 

[Werewolf]

.2k difference on the resister probably wouldn't make a difference on the controller as it's only ~2% out on a 9.8-10k resistor (IIRC it's within tolerance for a general purpose resister).

It sounds like the controller chip, or one of the joints is bad.