The Party Zone: party pooper

[capnbzarr]

Hey folks--the name's Matt; long-time pinballer, first-time poster.

I bought my first and only machine, The Party Zone, a few months ago on eBay from a Tacoma coin-op company.

At first, it worked fine (except for the rotating/talking head of Captain B. Zarr, which doesn't rotate, but that's purely aesthetic), but then switches 61 (shooter lane), 63 (Out of Control), 65 (skill shot), and 67 (DJ eject) started working only intermittently. It didn't occur to me at the time that they're all in switch column 6, so I bought new switches--upon later testing, I realized that the switches themselves are still perfectly functional. It was when I was replacing switch 67 without turning the machine off first (PZ was unfortunately built shortly before the innovation of having the opened coin door disable the high voltage circuits) that I short circuited something with the body of my soldering iron. The machine started showing a "ground short - row [#]" for every row that had a single switch closed, when it wasn't acting as though I was holding down the Volume+ button. I went on another pinball discussion board and asked for advice, and they pointed me to a website that suggested I might have blown out the switch matrix's voltage comparator (ULN2803A). I bought a new ULN2803A and plugged it in, and the machine worked again. Except that now all the switches in column 6 were dead.

I decided to fix column 6 later and just enjoy having a mostly-working pinball machine for the time being.

Well yesterday, I turned the machine on and didn't touch it for about an hour. At which point, I heard it, from the adjacent room, repeatedly making the "BONG!" sound that it makes when you power it on and it runs the self-test. All the illumination (including the dot matrix) was dead, and it kept making that sound every 5 seconds or so. As far as I can tell, it's rebooting itself over and over. And it started doing this when it was being untouched, in attract mode (in fact it hadn't been touched since I turned it on--when I first turned it on, it was behaving normally). On the CPU board, diode D20 blinks twice, with the "BONG!" sound happening on the second blink. There is a faint odor of burnt electronics, but I can't see anything obviously broken. I checked all the fuses, and fuse F109 (general illumination circuit 4) was blown, but I'm almost positive it was blown before this happened. I replaced that fuse but it's still just making that sound over and over when I turn it on. None of the switches has any effect.

So do any of y'all have any idea what's wrong with it? I ran into a CFF guy (sorry, I'm terrible with names) at the Lutz back when the only problem was switch column 6, and he suggested two of you guys (again, terrible with names but he did name two of you) might be able to fix it for me or tell me how to fix it. At this point I'm out of ideas so... Help me CFF; you're my only hope!

[videomode]

Jake or Eric would be the guys.

[eric]

The reset problem is likely (though not definitely) unrelated to your switch matrix problem. Have you added additional appliances to the circuit the pinball is on (like an air conditioner)? Check your wall voltage and make sure it's at least 115VAC.

[capnbzarr]

[revtest]

Hows the battery look have you or has it been upgraded to a remote battery pack could be some corrosion on the MPU???? I'd be happy to come take a look (I'm Jake by the way) pretty busy week though today would be the best bet or evenings later this week. My email is ( rev-test at pin-life.com ) shoot my your contact info.

REV

[eric]

Before diving into the MPU, I'd recommend making sure voltages are within spec on the driver board. Follow the link below and scroll down to "Check the Drive Board Voltages".

http://www.pinrepair.com/wpc/index2.htm#reset

BTW-Welcome to the board.

[revtest]

OH right it's a WPC game huh. I don't know why I always think that game is older than it is. +5 DC voltage drop possibly, definitely need to check voltages at the TP's .

[capnbzarr]

[eric]

All of the driver board voltages appear to be within spec though 4.94V is at the very bottom end of tolerance and a low 5V will definitely cause resets. 75V is actually totally fine as the 50V supply isn't regulated and isn't under load when you're taking your reading.

How does connector J101 look on the driver board? Try re-seating it with the power off and see if your 5V at TP2 is any higher.

ZC is the zero cross circuit.

[capnbzarr]

[eric]

Sorry, I just re-read your initial response and missed something. The IC marked D27C020 (i.e. 27020) is the game ROM and you should NOT see voltage of pin 32 of jumping around. It should be exactly what you see at TP2 on the driver board. Try checking voltage of pins 4 and 5 of MPU connecter 210. This is where +5V enters the MPU. What do you see?

[capnbzarr]

[eric]

Sorry, I did mean TP2 on the driver board and it should not be fluctuating. Remove J114, J116, J117, and J118 from the driver board and check TP2 again. What's the voltage? Any fluctuation?

[capnbzarr]

[eric]

OK, starting with J114 reconnect them one at a time and check the voltage at TP2. At what point does the voltage become erratic? Make sure the machine is turned off when you reconnect a connector.

[capnbzarr]

[eric]

Discharging the caps won't make any difference, and really by the time you sat down and composed that last message they probably had already discharged. Watch the LEDs on the board when you power down and you'll see what I mean.

At this point, I'd strongly recommend replacing BR2, C5, C4, and Q1. These, along with the board connectors, are the most common failure boints in the 5V chain.

Before you do that however, check AC voltage across pins 1 and 2 of J101. DMM on AC voltage one lead on pin 1 and one on pin 2. This is where the voltage that eventually becomes +5V enters from the transformer. Anything erratic here?

[capnbzarr]

[eric]

9VAC is right where it needs to be. Also worth noting that cracked solder joints at J101 will cause the 5V to be erratic and I also believe there's a connector between J101 and the transformer that could go flakey. Checking the AC voltage right at B2 would be a way to eliminate those suspicions but it can be really hard to get your DMM leads under the bridge without accidentally shorting something else.

At this point, the problem is just too intermittent and too erratic to pinpoint. I think the best thing would be to replace BR2, C5, C4, and Q1. While you have the board out you should also reflow the solder to connectors J101 and J114 and make the jumper mods recommended on Clay's site. This would eliminate a huge number of variables.

Not sure how much soldering experience you have, but this probably isn't the best "first project" to take on. Those bridge rectifiers can be a bear to remove and you could seriously damage the board by applying too much heat.

[capnbzarr]

Thanks for all your help. Sounds like I have my work cut out for me. I'm not that experienced at soldering but fortunately Jake has offered to help with the installation.

BTW, I was just testing the fuses again and found F116 had blown. I'm 99% sure I tested it yesterday and it was still intact. I'm not sure what to make of that...