donkey kong - wont climb ladders

feynman

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one thing after another with this machine :(

latest problem is i cant move up, i have eliminated the microswitch and the wiring, they are fine, and i dont think its the harness connector on the pcb becase i can read 5v across the ground/up pins...

what else can cause this problem? must be something on the board, i have reseated all chips...any help would be appreciated...

cheers
 
I would make SURE it's not the wiring or microswitch before messing with the PCB. It's very easy for the wiring to get pulled from a connector, especially if you're constantly taking off the CP to check things. I've had that happen on multiple occasions. Check the connections from the micro-switch all the way to the board (make sure no wires have been pulled loose). Cross check everything by swapping wires, etc.
 
thanks, i have a spare harness so have swapped the cp harness and the cp/pcb cable and tried a different microswitch with no change so i am sure of the connections...
 
one thing after another with this machine :(

latest problem is i cant move up, i have eliminated the microswitch and the wiring, they are fine, and i dont think its the harness connector on the pcb becase i can read 5v across the ground/up pins...

what else can cause this problem? must be something on the board, i have reseated all chips...any help would be appreciated...

cheers

I would say Arthritis... He's old. He was old 30 years ago, so he has to be in his 70's by now. :D

If he moves left and right and jumps, then the controls are probably ok. Could be a bad IC for Up and Down, or something related to the collision detection with Mario and the Ladders.

To eliminate the controls, do you have another PCB you can put in the cabinet (DK, DK Jr, Dk3)?
 
If you are absolutely certain the wiring is ok... then the problem is most likely the ls240 located at 2P on the CPU board. It takes the UP signal (among others) and makes it accessible to the CPU.
 
How did you eliminate the switch and wiring and come to a pcb conclusion?
To me, just sounds like a ground issue to that input.

Did you take a working direction and try to use that for an up movement?
 
same problem with two different harnesses, and the microswitch is working, i can move sideways by pushing up after swapping the connectors...
 
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ok so last night it spontaniously started working again, then problem became intermittent where jumpman would climb a couple steps then stop, repeatedly pushing up he would eventually get to the top of the ladder.

then today it was working perfect for a few hours but now he suddenly cant jump...

does that help narrow down the problem? am at a loss what to do :-(

cheers
 
If your is the 2-board version, sounds like a bad 74ls240 at location 4P on the CPU PCB. It handles the control interface between the buttons and the CPU.
 
yes its 2 board, can you buy replacements of that chip? not sure my skills or soldering iron are up to a job like that anyway but worth a try...

cheers
 
Heh.. actually I forgot I had already replied to this post. And the 1st time I looked at the schems I noticed 2P.. the 2nd time I noticed 4P. Both do the same thing.. So I guess it depends on how the controls are connected to the PCB. If it's through connector P5, then you'll want to change 2P. If it's connected through the P6 connector you'll want to change 4P.

74ls240's are available all over the place:
Mouser, digikey..even ebay.
http://www.ebay.com/itm/1PCS-74LS24...ltDomain_0&hash=item19d3a7911b#ht_1280wt_1397
 
ok so i replaced the chip at 2p, god dam they dont make those things easy to remove do they - soldered to both sides of the board, and a bunch of caps also soldered both sides were in the way of the chip legs.

i was just not able to get it off without damaging some of the tracks, and it was just to fiddley to solder back on the parts side anyway...

i ran wires from the chip legs and stuck it on the back of the board, and followed the tracks to points i could solder the wires to...

anyway its acually working! am really pleased, if you saw the dog ugly hackjob i made of this you wouldnt believe it worked...

am not convinced it will hold up long term but for now i finally have my dk working :)

thanks ajcrm125
 
Awesome! And that reminds me... I'll be doing an instructional video soon on how to remove IC's flawlessly and with the cheapest tools possible. So stay tuned for that.
 
nice one, maybe i should have waited...

main problem was the iron was struggling to melt the solder and it just was not possible to be precise. and also there was not clear access to this particular chip...

also my technique is probably bad, look forward to your demo...

cheers
 
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