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Archive for the ‘Repair Log’ Category

G07 monitor chassis wash

Wednesday, March 10th, 2010

This topic has been given a lot of coverage in the various newsgroups and arcade collecting forums. I’ve done lots of research and read all the comments I could find. I’m also lucky enough to have a good friend that knows a great deal about electronics and was kind enough to share the pros and potential cons of bathing them. After talking with him I decided to give it a go.

G07 chassis

I neglected to take a couple of before pictures to show the nasty grime covering these three G07 chassis, but we’ve all seen similar parts. Any arcade pcb’s that have been sitting around in a warehouse for 20 plus years are bound to be covered with crud. Makes it hard to see what you’re working on when trying to do repairs and sometimes a standard cleaning just doesn’t do the trick. So into the dishwasher they go! (more…)

Repair Log: Poker Machine: 022010

Saturday, February 20th, 2010

Patient: Poker Machine UR, manufacturer unknown
Technician: Chris M
Problem: Game will not power on.
Troubleshoot: This poker game is in very nice shape other than a broken corner on the coin box door. I’m used to seeing these poker’s in horrid shape. This one was so clean I was hopeful for an easy fix. I unloaded the game in my garage and gave it a quick once over. Checked all the fuses and they were fine. Looked over all the connections and found a bad crimp on the single crimp wire near the transformer, the wire just pulled right out. Must have been a bad factory crimp as the wires were stapled in place and not easy to move around.
Solution: Pulled off the bad connector and extracted the pin. Crimped a new male pin in place and put the connector back in place. Powered it on and game fired right up with a nice picture on the monitor. I played a few hands and everything seems to be working just fine. I have no space for this game, so it will be hitting the sale page. Drop me a line if you have any interest in a nice working Poker Machine.

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Repair Log: Cube Quest: 011410

Tuesday, January 26th, 2010

Patient: Simutrek, Cube Quest UR
Technicians: ???
Problem: Game would power up, but die after a few minutes. No sound.
Troubleshoot: I was just a lucky observer with this project, so I can’t provide too many details. (I will ask and update if possible) I did get to see the huge board set and the massive cage that housed it. What a monster.
Solution: The easiest way to work on this board set was to have it out of the cabinet, but the cage and cabinet has connectors that are all dependent upon one another. Sticking your head into a dark cabinet to probe with an Oscope is not a fun time, especially when the cab is in the garage during a wonderful Midwest winter.

cube-quest-pcb

The cage itself prevented effective troubleshooting, it was just in the way. What to do? Build an equally complex testing harness and power supply, of course. After many days of painstaking labor to develop and build a dedicated test station for Cube Quest, the tech was finally ready to get down to business.

After only a short time, the technician was able to get the board working, as you can see. One interesting bit about this game is that it was designed to work and play even if (or should I say when) the laser disc player failed. What you see here is game play minus the laser disk effects. Still pretty cool. The next step is to restore the sound and then connect the laser disc player to see if it will all work together. Want more info about this particular game? Check out the post over at rotheblog, happy gaming!

Repair Log: Space War: 081209

Thursday, November 5th, 2009

Patient: Vectorbeam Space War UR
Technicians: Mark H, Bill K and Chris M
Problem: Slightly shaky graphics during game play.
Troubleshoot: After discussing the problem with Mark H, I pulled the monitor and got it over to his place for testing. He didn’t find any issue with the monitor and suspected the ribbon cable, which I hadn’t brought along. Apparently the ribbon cable is a common failure point on the old Vectorbeam and Cinematronics games, similar to those crappy MCR ribbon cables that are always brittle and prone to failure. Good idea to just replace it. Here’s the old red ribbon cable attached to the monitor/pcb. (more…)

Repair Log: Warlords: 081409

Wednesday, September 9th, 2009

Patient: Warlords upright
Technicians: Bill K and Chris M
Problem: Continuous tone with intermittent screeching noise. Volume must be turned all the way down to play the game comfortably. Listen to this sound bite on You Tube and you’ll get the idea.
Troubleshoot: We first attempted to swap in a known working AR II board, but there was no change. Next step is to check the audio oscillations to see where they are originating from. We checked the audio test points on the pcb with an oscilloscope by hooking one lead to the test point and the other to ground. This was the resulting square wave display.

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The scope leads were then connected to the sound test points on the AR II, with the same result, except the square wave was amplified (larger). This ruled out the AR II pcb as the cause of the problem because the oscillations were the same. The noise was originating from somewhere else. We had to take a closer look at the schematics which I didn’t have on hand, but could easily find at the arcade archive. The schematics show that the audio section on the pcb can be traced back to leg 37 on the pokey, a likely culprit as they are known to fail. Quick history of the name…”The pokey is an I/O chip used by Atari in many of the classic era games, its name comes from POtentiometer and KEYboard, as it was commonly used to sample (ADC) potentiometers (such as game paddles) and scan matrices of switches (such as a computer keyboard).” – Wikipedia. We powered down and swapped out the pokey with a known good chip, but there was no change. Isolating pin 37 on the pokey, responsible for audio output, also gave us the same wave display result on the o-scope. This ruled out the pokey.

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Since it appeared that the pokey was good, the likely problem was now with the audio portion on the pcb. That was all we could do at this point because I didn’t have any of the audio amp chips on hand to replace or piggy-back onto the existing chips. Bill took the board home to change out the chips and capacitors from the audio section. I took this opportunity to lay the game down and add some gliders (levelers with nylon). This would allow me to move the game around a lot easier without damaging my floor like the metal levelers do.

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Picked up the repaired Warlords pcb from Bill along with a spare pcb Bill had on hand, just in case. Installed the original pcb into the game and fired it up. Same problem with absolutely no change. Installed the spare pcb and got the same noise issue, but at least I was able to verify it was working and also potentially rule out the pcb as the noise problem. At this point I was a little irritated and because I use tokens to run my game room, the coin door on the cab was open to allow me to easily add credits. I closed the door a little rough and got a fluctuation in the sound, interesting. Opened the door and noticed the sound fluctuated as I moved it around. Jiggled the coin door wires and got the same changes. So now it appears that the connection to the coin door is the issue. With so many wires and connectors to check, this is going to be a pain. Bill stopped by later that night to poke around at the coin door. He moved wires, jiggled coin mechs, pulled on coin shutes and then moved the slam switch. Huge change occurred. Bill pulled the leaf apart on the switch and the sound vanished, bingo!

Solution: Slam switch on coin door was closing/sticking with door movement causing leaf switch contact and the horrid sound. A simple piece of blue tape between the switch contacts keeps them from closing and the sound is gone. I guess it pays to check ALL the simple solutions before running the repair gauntlet, but at least I learned a few things.