IM BACK, Kind of.

I got out of pinball for a little while but it sucked me back in. I am in the middle of doing a complete restoration of a Bally Xenon. I am installing a CPR reproduction playfield and am repainting the cabinet using Twisted Pins stencils. I also have a Williams Black Knight and a Stern Lightning waiting in the wings to be restored; well the lightning really just needs a good shop job, its in great shape. I will be uploading pictures shortly and will try to make some comments on what I am doing. Layton

Well I finally have something to put into the, and stuff category. I recently acquired a 1979 Atari asteroids arcade machine. The machine was in overall good condition, the cabinet needed some small repairs, and it needed new locks and keys. There was just one small problem the monitor in this machine was very dim even with the contrast and brightness turned all the way up. I have never worked on a monitor before but I am good with electronics so I figured I would give it a shot and repair this monitor. After carefully removing the monitor and discharging the picture tube I removed the High Voltage cage and found a huge problem, the High Voltage Rectifier Diode was completely blown away from the flyback. Well this will need to be rectified, pun intended. I found the diode that I needed a H1809 at http://www.arcadechips.com and placed an order for one. Will I was at it I also sprung for a capacitor kit for the monitor, the game PCB board and a new BIG Blue Capacitor for the Atari power supply from The Real Bob Roberts. After installing all of these parts this machine works flawlessly and the picture is crisp and bright. For some reason I did not take a lot of pictures but I will put up some of the ones that I did take. This was a fun little project, and very rewarding.

Fireball II Finished

Well here it is one finished machine. I still need to put my freshly painted legs back on the machine, but that is it. This machine now plays great and is ready for people to enjoy again.

Board repair

When I first started cleaning up the boards and removing damaged components I was trying to be relay careful. But these boards where so damaged that no amount of being careful was going to save all of the traces and solder pads. Getting all of the old solder and other nasty junk off of these boards would be no easy task but I managed. When all of the damaged components where removed from the boards I sanded it clean and gave the boards a vinegar and water bath to neutralize the battery acid. I made on big mistake when working on these boards, when I pulled the game ROM's off the board I promptly misplaced them somewhere and had to order new ROM's. This caused me a lot of headaches, the new ROM's are larger 2732 EPROM's that have more memory than the old ROM's. I forgot to change the jumper settings on the board so that the boards could address this larger memory space, but more on that problem later. After replacing the damaged components, socketing all of the IC's with machine pin strip sockets, and replacing all of the male header pins on the boards it was time to power them up on the bench. I hooked the board to +12 and +5 volts that it needs to boot at test point 5 and 4, then turned on my power supply and what did I get, a locked on solid LED. Remember how I said that I had forgotten to change the jumper settings on the board, well that was part of my problem. After changing the jumper settings I still had some broken traces around the 5101 ram, three of them to be exact. These traces took quite a wile to find, I had to trace each pin on almost every IC to find all of the broken traces, My DMM relay got a workout. I found and fixed the broken traces and powered up the board again, flicker then flash 1,2,3,4,5,6 on the LED. my board was now booted. I was pretty happy with myself when I got the board to boot.

While I was working on the MPU my lab partner was working on the lamp driver board. I do not know it all of the components on that board where good or bad but they all looked terrible so I decided to replace every silicone controlled rectifier on the board. The solenoid driver board and the squawk & talk sound board looked to be in good shape so the only thing we did to them was to replace the capacitors on the sound board, and do the upgrades to the solenoid driver from Clay Harrell's guide at marvin3m.com.

Now it was time to put everything back together. When I first fired up the game everything looked to be going great, a few lights out here and there but nothing major. I put some credits on the game and started to play, what the flippers do not work. Well back to the drawing board. I first checked the power to the coils and was getting a perfect 43 volts to both sides of the coil, we defiantly have a ground issue. Good thing that I have schematics, first thing to check is the driver board. I checked the voltages at the transistors and everything reads fine but still no flippers. There is only one place to look I guessed that I missed a broken trace at the PIA on the MPU, and I was right. I pulled the MPU and the PIA at U11 and there it was a broken trace. One of the pictures that I am putting up today has a picture of this problem that I have circled in red. How did I miss this? After fixing this trace the game now works 95%, there are still some lights out and most of these light problems where more trace problems on the lamp driver boars. After pulling the lamp driver board and fixing these traces then doing some minor tweaks and adjustments to switches the game now works 100%. I will be putting these pictures up in the next post to this blog.

More Circuit board damage

Circuit board damage

Here are some pictures of the circuit board damage in this machine. The Ni-Cad battery on the MPU had been leaking for years and did some very bad things to the MPU and lamp driver board. Here are the initial pictures of these boards.