Archive for May, 2007

Sprint 2 – Stiff Steering and Hard Shifting

Wednesday, May 23rd, 2007

Problem: Stiff spinning steering modules and hard shifting between gears

(Quick little story – while bringing this beast into its location, I fell and got pinned under it for a few minutes. It is amazing how much having your chest compressed effects your ability to call out for help! :)

OK – onto the next issue… Its steering wheels were pretty stiff, and if you tried to give them a good hard spin they would come to a halt within a couple of turns. Removing and disassembling them was easy. Turns out the problem was that the old grease in them had coagulated/thickened so that it was about as viscous and sticky as cold honey!

Getting the grease out of the barrel and off of the shaft and sleeves literally took ~10 minutes (for each module) with some rubbing alcohol, elbow grease and rags. I had a friend helping me (Sean) and we each tackled one sterring wheel each.

After getting that old gunk out, a quick application of some light lithium grease on everything solves that problem – the wheels will now spin for at least 10 turns easily.

For the shifter modules, I just applied some powered graphite to the shifter “ball” at the opening of the shifter and after a few shifts to get it all around, the shifts are much easier now.

Solution: Cleaned and lubricated the steering modules, lubricated the shifter modules.

Note: One of the steering modules has a broken shaft/cone, which caused the wheel to be off-center, and it was being held in place strictly by the force of the retaining bolt that goes through the entire assembly. I managed to get it a bit straighter than it was before, but it still is broken internally. Not sure if I want to go through sanding down the two halves to try to get them melded or epoxied together – I am afraid of shortening the cone too much and causing problems. The wheel works and the game is playable, so I might just leave it as it is.

Punch-Out vertical foldover/overdraw

Monday, May 21st, 2007

The Punch-out that I recently obtained has a monitor issue (a monitors issue, really). Both displays are bring drawn starting ~2″ from the bottom of the monitor, and the upper few inches are being overdrawn on the same horizontal plane.

In other words, the beam is scanning left/right correctly but is starting too low and is not going high enough (vertically) to complete drawing the image correctly – the beam stops going up and keeps trying to draw the rest of the screen on the same horizontal line, causing a higher-intensity line to be seen (images below, apologies for their quality – I guess I shoulda taken off the Plexiglas first).

Top Monitor Overdraw Bottom Monitor Overdraw

The overdraw is visible in the image, but it is not obvious from the images that the bottom of the image is ~2″ higher than it should be. The overdraw looks like a classic capacitor problem to me, although I admit that I am not that familiar with the “starting too high” problem and I am guessing that the two are related. At least, the two things being related kinda makes sense in my mind…

I have cap kits from The Real Bob RobertsTM (highly recommended for all kinds of arcade-related parts, BTW!) for the monitors and will be capping them shortly.

More to follow…

Sprint 2

Sunday, May 20th, 2007

Problem: Static garbage on screen

Purchased a Sprint 2 in non-working condition. Saw a picture of it, monitor worked – it showing what appeared to be static garbage on it. Got it home and confirmed that yes, it is showing static garbage (first image below). Turning it off for a couple of seconds and then back on again keeps pretty much the same garbage display, but sometimes gets some sounds out of it (engine and/or screeching sounds). Moving the self-test switch does nothing. First suspect that CPU is not running, because the screen is static (i.e. not changing while the game is on).

Sprint 2 - Before

After checking the usual suspects (voltages, loose wires, harness/wire burns because this is an older Atari game…), I yank the CPU to see if I get the same results (to narrow it down to the CPU). This causes a different effect, a screen filled with a single character and I get sound, so I presume for now that the CPU is working and the problem lies elsewhere.



Sunday, May 20th, 2007

Problem: Dead

Purchased a Punch-Out in dead condition.  Got it home, still dead.  Rocking the game and/or whacking the sides a bit got a brief flash of light on it so I went in and reconnected all connectors.  Game then came up right after that.

A little adjustment to the micro-switch arms and the game is playing nicely.  Still need to rebuild the joystick as it is stiff and sticks a bit.

Solution: Re-tighten/reattach all (power?) connectors