Issue with Sound in Spy Hunter Upright

[Jasonbar]

Howdy-

My Spy Hunter has exhibited some occasional strange sound issues & I'm looking for help in resolving them.

The other day, when I played, a quiet static started up in the speakers & then grew louder & louder & louder until it was quite loud. The game sounds & music were still also playing normally. Turning the left or right volume knobs made no difference. Then the sound went away.

Today, upon power-up, there was a loud hum in the speakers. Again, the in-game sound effects & music were still there & fine, though the hum was quite a bit louder, and adjusting the volume pots didn't affect the hum.

I was on my way out the door to work, so I didn't get farther than wiggling a few of the connectors, which made no difference.

Know where I should start looking? Or, if somebody knows which board(s) is wrong, got a spare for sale?

Thanks,
-Jason

[Clownzilla]

Try wiring in a temporary speaker to see if the problem continues. It doesn't have to be permanent, just for testing purposes.

[Jasonbar]

Problem solved! Here's the scoop on my research & my fix:

Spy Hunter is very sensitive to the power supply not being tuned in. Capacitors go bad over time, the power supply goes wonky, & the sound boards start complaining & freaking out.

I ordered replacement 55000 microFarad & 100000 microFarad capacitors (from arcadeshop.com for $20 & $25) for the power chassis, installed them, & I was back up & running! Spy Hunter still had a hair of background hum/hiss/static, but it's very quiet relative to the game sounds. I had a bit of wave on the monitor that I didn't recall seeing before, & my accelerator pot was way out of wack (surely due to the fact that the ADC on the board is reading 0-5V from the pot & that 5V changed when I changed the caps in the power supply.

So, I went 1 step further & installed the $75 switching power supply replacement kit (also from arcadeshop.com...I'd bought these items all at once, so I might as well use them--plus, this kit bypasses another old board w/ a modern switching power supply, so that's little insurance investment...).

1st, I wired the new switching PS to a brand new 3-prong cord & plugged it into the 3-prong outlet on the power chassis. Oddly, that outlet is always hot, so part of the game would always be on when plugged in, so that was no good. Also odd is the fact that, of the 3 connectors on the little kit board, 1 goes straight back to the big old power chassis, so the chassis can't be removed altogether with this kit. It replaces one of the power boards instead. Oh, this might be a good time to mention that the manual makes note that Spy Hunter is the red-headed stepchild of this era of Midway games, & you might need to try a higher-current switching power supply, installing a jumper on the Cheap Squeak Deluxe board, or sacrificing a chicken (OK, I made that last one up...). This would be good to know *before* buying this kit! :\

Powered everything up, tuned in the switcher PS 5V to 5.1V per the manual, and the game worked fine still. Phew! Monitor seemed a bit less wavy too--bonus!

Then I looked a little closer @ the manual & kit & realized that the kit includes 2 splice wires to get the switcher's 120VAC from the marquee light instead of the chassis, as the marquee light is (obviously) switched by the main power switch on the cabinet.

Did this step. Game still worked great. Monitor waviness still good.

Realized I was no longer grounding the switching PS to the main PS chassis, so I re-plugged my hacked 3-prong cord in & tied just the ground line between the old & new power supplies.

Still good!


However, I have had a beeear of a time trying to tune in the accelerator pot. If I set it to 0B (not touching the pedal) per the calibration screen, then my top speed is noticeably slower than it ought be. If I get the top speed set, then the car idles along very slowly when my foot's off the gas (it ought stay put). Also, throttle response seems a tad flaky. I gave up after >1hr of tweaking & left it where the car creeps at idle, & it's *almost* OK. There is a *sliiight* bit of backlash in the gear mesh, but not enough to account for this much tuning difficulty. I think my pot's gone south--it ought be cheap enough to slap a new one in to test it.


Anybody got a source on Spy Hunter pedal pots?

Thanks
-Jason