spy hunter accelerator calibration problems

tron guy

Super Moderator
Staff member

Donor 12 years: 2011, 2015-2025
Joined
Jun 26, 2007
Messages
23,145
Reaction score
2,593
Location
Eureka, California
I went to my buddys house today because he picked up a spy hunter that needed the pedal calibrated every time you turn it off.

I was told that it needed a battery on there to remember the calibration.
So I took a bob roberts mcr battery kit and installed it.

The problem is, it's very hard to get this thing calibrated properly. The machine says the pedal should be 0B to be calibrated. You can lightly step on the pedal and get it to 0B.
When I do that the game hauls ass but the gas pedal works more like a brake instead of an accelerator. It almost goes too fast at this point.

The guy he bought it from told him to go to accelerator calibration and step on the pedal 3 times then put it into game mode. It worked when he did it at his house, but when we do it, the car sits on the side of the road and won't accelerate at all.

The pedal is a little rough to push down. Should I replace the pot for the accelerator?
Also, what else?

Additionally, the +5 has been hacked and is running off of a switcher. Does that have any impact of the high score save or calibration save capability?
 
I would suspect the pot is either not placed and tightened correctly and/or needs to be replaced. Honestly the step on it three times thing sounds like the pot is not tightened and positioned correctly and therefore not catching and turning correctly. Stepping on it multiple times may have been the guys way to get it to turn a bit in the correct direction each time he stepped on the pedal. On my machine the pot placement needs to be adjusted. It actually has the same top speed slow down that you describe but only when the pedal is to the floor.
 
> I was told that it needed a battery on there to remember the calibration.

Yes, that's correct.

> The machine says the pedal should be 0B to be calibrated. You can lightly step on the pedal and get it to 0B.

Ignore the calibration screen for the moment. If you go to the user input screen and lightly and slowly step on the pedal, what number does it start and end at and does it give you a nice smooth progression?

Then go back to the calibration screen and calibrate as you suggested and go back to the user input screen. What number does it start and end at and does it give you a nice smooth progression?

When calibrated properly you want a starting value of 0 and a max value of around 22h with a nice smooth progression between them. If the number does something crazy (like start going backwards in the middle of pressing the pedal) then you probably need to calibrate it.

If you get inconsistent numbers coming back then you probably need to replace the pot.

> Should I replace the pot for the accelerator?

If it's the original blue pot, almost definitely yes. I have yet to hear of an original gas pedal pot that still works the way it should.

If it's feeling grindy when you press it, check to see if the gear that turns the pot is meshing correctly with the larger gear from the pedal.
 
is the high-low shifter working correct

yes

and to the calibration numbers, initially I was getting as high as 19 or so, then progressively it got worse. somewhere around 17, then only to 11 by the time we were done messing with it.

It did seem to have a smooth progression when I went to the other screen mentioned before.

I think the pot needs to be replaced (my initial though) I was looking in the back when my buddy stepped on the pedal and it didn't look like it missed a gear, but it looked like to turned very rough, and it feels very rough.

He can play it the way it is now, kind of. It's on super speed and if he hits the pedal it's a brake, lol.

where can I get the right pot for this?
 
> and to the calibration numbers, initially I was getting as high as 19 or so, then progressively it got worse. somewhere around 17, then only to 11 by the time we were done messing with it.

It sounds like the gears and/or the pot itself is slipping. It shouldn't be grindy when you push on the gas pedal.


> It did seem to have a smooth progression when I went to the other screen mentioned before. I think the pot needs to be replaced (my initial though)

If you're getting a smooth progression of numbers then it's probably not the pot. When the numbers jump around then it's probably the pot.

> it looked like to turned very rough, and it feels very rough.

Either the gear or the pot itself is likely slipping.

> He can play it the way it is now, kind of. It's on super speed and if he hits the pedal it's a brake, lol.

I would expect that if you went to the user input screen and reported the number with his foot off the pedal and the progression forward you'd find that the starting number is relatively high, it "wraps" at some point when he presses on the pedal, and then is returning low numbers when he presses hard.

There's no sense in trying to calibrate this -- you likely have a physical problem (slipping gear/pot) and maybe a bad pot. You won't know the latter though until you address the first issue.

I'd suggest unscrewing the adjustment screws on the plate that holds the pot in, take the pot out, and on the calibration screen turn the pot until it says 0B. Then calibrate it. Then go to the user input screen and check out the progression as you slowly turn the pot shaft. If you get a nice smooth progression then your pot is good. You should start at a number of 0 and the number should increase as you turn the pot.

Now with the pot reading 0B in the calibration screen, put the pot back in and wiggle it until the gear on the pot shaft meshes nicely with the gear from the gas pedal. Tighten it -- does the 'rough' feeling go away?
 
Last edited:
> and to the calibration numbers, initially I was getting as high as 19 or so, then progressively it got worse. somewhere around 17, then only to 11 by the time we were done messing with it.

It sounds like the gears and/or the pot itself is slipping. It shouldn't be grindy when you push on the gas pedal.


> It did seem to have a smooth progression when I went to the other screen mentioned before. I think the pot needs to be replaced (my initial though)

If you're getting a smooth progression of numbers then it's probably not the pot. When the numbers jump around then it's probably the pot.

> it looked like to turned very rough, and it feels very rough.

Either the gear or the pot itself is likely slipping.

> He can play it the way it is now, kind of. It's on super speed and if he hits the pedal it's a brake, lol.

I would expect that if you went to the user input screen and reported the number with his foot off the pedal and the progression forward you'd find that the starting number is relatively high, it "wraps" at some point when he presses on the pedal, and then is returning low numbers when he presses hard.

There's no sense in trying to calibrate this -- you likely have a physical problem (slipping gear/pot) and maybe a bad pot. You won't know the latter though until you address the first issue.

I'd suggest unscrewing the adjustment screws on the plate that holds the pot in, take the pot out, and on the calibration screen turn the pot until it says 0B. Then calibrate it. Then go to the user input screen and check out the progression as you slowly turn the pot shaft. If you get a nice smooth progression then your pot is good. You should start at a number of 0 and the number should increase as you turn the pot.

Now with the pot reading 0B in the calibration screen, put the pot back in and wiggle it until the gear on the pot shaft meshes nicely with the gear from the gas pedal. Tighten it -- does the 'rough' feeling go away?

thanks

since it is a pain to go to his house, I would like to have a new pot in hand when I go next time. Anywhere know the value, or where to get this correct one?
 
Mouser has them.

I use: 360 degree 1K linear pot 882-eup1125-1K

Radio Shack has some too with very long shafts. 271-1714. I bought one to play with but didn't put it in my game. It's not 360 degrees and I'm not sure if it's as durable.
 
Last edited:
You'll also have a little bit of work in store for yourself.

When you pull the plate out that's securing the pot you're going to have the pot itself with a gear attached to the shaft and the gear is secured by a small pin.

You'll have to carefully knock the pin out (hint: have it pressed up against a piece of wood when you use the hammer and pin punch) and it should come out without too much trouble. For some reason that I can't fathom, when you try the same thing with the gear/pot end pressed up against concrete the SOB won't come out.

Next you'll need to drill out an exact sized hole precisely in the same position on the new pot shaft. Then re-secure the new pot with the pin you punched out earlier.

You might want to buy a couple of pots because one mistake and you're screwed. I learned the hard way with mine, even with lots of generous help from CDJUMP.

Anchor the shaft of the pot on the far end, away from the pot itself in a vise. Drill carefully to keep the shaft centered all the way through. Don't use a drill with weak batteries. (LOL; I ruined 2 pots this way before I bought a new battery for my Makita; the next pot was flawless). Go easy on the pot when you're drilling.

This isn't hard but it'll take longer than you expect.

When you put the new pot back into the game you want to start with a very low number on the calibration screen before you calibrate it. The main thing is to not let the numbers wrap when you press the gas pedal all the way down and you can ensure this by getting a low number when you calibrate. 0B is fine but any low number will do.

You'll likely have to fiddle with the calibration and turning the pot until you're happy with it.

What really matters: the numbers returned in the user input screen. You want 0 with your foot off the pedal. You want around 21-23h when the gas pedal is pressed all the way down. And of course you want a smooth progression from 0 to your max range.

When you get 0 to 21-23h, you're golden. Make sure that gas pedal pot plate is tightly screwed down.
 
Last edited:
Mouser has them.

I use: 360 degree 1K linear pot 882-eup1125-1K

Radio Shack has some too with very long shafts. 271-1714. I bought one to play with but didn't put it in my game. It's not 360 degrees and I'm not sure if it's as durable.

I saw your recommendation and ordered a couple of the 882-eup1125-1k pots for my Spy Hunter. I just pulled the gas pedal and the old pot was 5K. Are you saying that a 1K pot will also work? It has been mentioned elsewhere (http://forums.arcade-museum.com/showthread.php?t=169443) that it is a 5K pot.

Thoughts?
 
1K works fine. I've got one in my SH right now.
 
Another hint -- spend the time to fine tune the calibration once you get the new pot in there. Foot off the pedal should return 0, floored it should return around 21-23h in the user input screen.

If you don't fine tune it you're kind of wasting your effort. You don't want the car creeping forward with your foot off the pedal and you want to get all the speed out of the car that the game allows w/o causing weird side effects.

Let me know how the replacement works out for you!
 
Thanks for the tips. I had been reading a lot about the pot replacement and calibration before I did it last night, as it seems there are lots of posts about it. And rightfully so, cause what a pain in the ass it was!

Replacing the pot wasn't too difficult (although the hole I drilled through the replacement pot shaft was slightly off-center, and hence the pin wouldn't fit all the way through). But I had to pull the whole pedal assembly out the front of the cabinet every time I wanted to adjust the pot position, because I couldn't get any tools in there with it in place. So it went like this: Check the travel in the User Input screen; walk around back of the machine and disconnect pot; walk around front and pull pedal assembly out; adjust pot position; put pedal assembly back in; walk around back and connect pot; walk around front and check again; rinse and repeat (probably 5 times!). If I had any molex connectors I would have made an extension cable to allow me to keep the pot connected while the pedal assembly was pulled forward from the cabinet. Phew!

I finally left it at 00-24 in the User Input Screen. The pot calibration screen shows it at 0C (instead of 0B) but it seems to work well and I was sick of adjustments. When the little turbo tire-screeching flames come on, are they supposed to stay on, or just a little burst before they go off again?

I have to say, I don't think I have ever played a properly calibrated Spy Hunter, now that I have seen what it is supposed to be like!

One more question: would the gas pedal sensitivity *change* if I use a 5K pot instead of the 1K replacement?
 
Last edited:
Hey congrats!

You're supposed to just get a burst of flames when you hit the turbo, not flames all the time.

There was no need to pull the entire pedal assembly out to adjust anything -- I never removed mine. There's no tools required to adjust it other than a screwdriver. You should be able to easily access the pot from the back. Here's a picture I took with my original pot. Not the best picture but you can see where the pot goes in and the little gear meshing with the bigger gear.

attachment.php


I started by putting the pot manually to roughly the correct position (calibration screen showing a low number), calibrated it, then carefully put the pot so the little gear meshed well with the bigger one, and snugged up one screw on the pot mounting plate. Then I'd walk around front and go to the user input screen and press down on the gas pedal and look at the readings. If it needed to be adjusted up or down, then I'd go back around into the back and loosen up the screw, turn the pot a bit, re-tighten the screw, and repeat. It took me 4-5 times to zero it in just the way I wanted it. Then I tightened both screws down snugly.

I think you made it a bit harder than it had to be but you got there in the end! And don't worry about the pin not going all the way through -- mine doesn't either.

> I have to say, I don't think I have ever played a properly calibrated Spy Hunter, now that I have seen what it is supposed to be like!

Yeah, tell me about it -- you don't realize what's missing until you get it back again. It's supposed to be an 800hp car and with it adjusted properly it feels like it!

Don't know about using the 5K pot -- I don't think it would matter because people have described using all different ranges and they all seem to work fine. The thing that would definitely change the sensitivity is the degree range of the pot. If you were to use a 90 degree range pot the pedal would be so sensitive it would be insane. I think the one I provided the link to is 300 degrees but has 360 degree rotation -- can't remember.

It is kind of a pain to replace it but it's not only well worth it but if you had to do it again tomorrow for a buddy you'd probably do it in 1/3rd the time now that you know the ropes.

I could do 5 SH's now in the same time I took to do it my first time on my game. That's why I've spent all this time on here trying to document this so other people won't get bogged down like I did. :)
 

Attachments

  • DSCF1473 (Small).JPG
    DSCF1473 (Small).JPG
    44.3 KB · Views: 81
Last edited:
Well, mouser and xon have sold out of those 1k pots- we're going to need a new source. Or someone really nice could sell me an xtra :)
 
Back
Top Bottom