PCEngineFans.com - The PC Engine and TurboGrafx-16 Community Forum
NEC TG-16/TE/TurboDuo => TG/PCE Repair/Mod Discussion => Topic started by: Lemony Vengeance on February 18, 2014, 08:28:42 AM
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hey all,
Just picked up a CG with R-type I and II with a pad and while the console plays perfectly the pad doesn't. It recognizes up and down, but when I press left it hits the run button as well. The right direction is the fire button. I'm not sure what's wrong..
Has anyone encountered this?
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Sounds like something is wrong with the chips in the controller. For two button game pads, there's a line switching chip and a turbo fire chip (unless it's the original non turbo pce gamepad). The chips are off the shelf parts, just make sure you get the replacement kind (if it's an HC chip or such, get the HC series part).
IIRC, the 74xx157 chip is the line select (outputs either start/select/II/I or Up/Down/Left/Right). The 74xx163 is the auto fire chip. Sounds like the problem is with the '157 chip.
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according to datasheet, state of the pin 1 "s" of the HC157 select 1 way on 2 (demultiplexer), I can see that with this schematic
http://www.archaicpixels.com/index.php/Controllers#Schematic
that run button (pin14) is multiplexed with left (pin13) and right with button "II" .
check alignment of pins of your pad connector (do you console works with another pad ?)
check if solder is clean on pull up resistor (47Kohms between pin 1 of hc157 and 5Volt)
while pad is open check wires of your cable are not damaged and check alignement of copper part who made selection on 3 position button turbo, the fork should not be twisted or contamined (clean it with alcohol)
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Will do. Thanks!
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If the pad isn't working out for you, many prefer tampons.
LOL, good one!
checked.. clean solder, clean turbo selector, everything looks very clean clean. :/
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I have nothing productive to add to this conversation. I just wanted to go on the record that I think "Lemony Vengeance" is an awesome handle. :D
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I have nothing productive to add to this conversation. I just wanted to go on the record that I think "Lemony Vengeance" is an awesome handle. :D
Thanks! I've had it for about 10 years now :D while a relative noob in the PCE scene, I'm well known in arcade circles.
on a lighter note, I added a transistor RGB amp to my Core Grafx, complete with 8 PIN DIN. Even made my own scart cable :). just don't have a pad to play with. Next step, replacing the IC. Will the Genesis pad's IC work with the PCE pad?
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Omg, Lems is here! Hey, if you want to borrow one of my extra pads hit me up in slashchat, that would give you something to play with until you fix this one.
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just to update you all, I replaced the IC and it's now working!