I have reset issues on Indy 500. I've read the pinwiki section on resets, it just isn't clear on a couple of points. I sometimes get a reboot right at start up, and other times I can play for a few minutes, and seems more likely when flipping both flippers.

Pinwiki mentions 9VAC coming from the transformer. At J101, I measured 7.8V - 8.0 V on pin1 and 7.3V - 7.8V on pin2 after a few tests and reseating connectors.

BR2 output is 8.64V and TP2 is 4.99V. Pinwiki says about 9V: is 8.64V close enough? Or is this lower because of the lower AC in I'm seeing?

Any thoughts on whether these readings indicate problem is before the board, or should I keep investigating?

Thanks for those tips. C31+ reads 5.0V, and ROM P32 also at 4.99V. J101 P1-P2 is 8.8VAC. It seems I need to investigate further as those appear okay.

I just played a few games with DMD disconnected. No further resets, so I'll take a look at that carefully.

I cleaned and reseated both sides of the DMD power connector, and resets are gone. Pins were a little tarnished. If it comes back, I'll replace those connectors.

Seems you are right, maybe it was just good fortune. I only reseated particular connectors between testings, and it looked like it was the DMD connection. Pinwiki did mention an instance where DMD was to blame, but after more playing, I still got reset with DMD disconnected.

Then I checked the flipper coils, and did find a broken diode. I replaced that, but still got a reset, so the search continues.

Since I have 5.0 on the CPU board, I didn't think it would be that connector, but rather some kind of strain / drain issue. But I suppose it still could be those connectors after all.

I eventually realized the times it seemed fixed after I did something was really just a matter of the machine having been on long enough to warm up. After about 5 or 10 minutes of being on, it no longer resets. I'll replace the thermistor once I get one to verify. Tomorrow morning rather than cold boot, I'll pre-heat the thermistor with heat gun and see if those resets go away.

Sorry, I wasn't specific enough. I reseated each of those connectors between test plays. Sometimes it seemed like I had fixed it, but then I noticed the coil.

That coil was a mess, and the whole diode was missing. I decided to remove the whole coil and replace both diodes on it. It took a while, and when I finished, the machine was resetting like crazy. I wondered if I messed something up on the coil, that was the only change, but I measured the coil and it was good, and I did a careful job with the diodes, removing all old solder and old diode legs. After more test playing, the resets subsided. I finally realized it was the machine was getting warmed up.

This morning, before turning on, I heated up the thermistor with my heat gun until it was hot to touch. I turned on, and still got a reset. I really thought that would be it. Then I played for a couple minutes, another reset. Then I played for 15 minutes, no more resets. Is there anything else that could be warming up and work better?

I'm going to let it cool down and read voltages on cold start and after it warmed up for a while.

So I hooked up clip to TP2 and to meter to watch the voltage from cold boot. It starts at 4.95V. In about 1 minute it climbs to 5.0V. In another 5 minutes it slowly reaches 5.05V. Playing with J101 (thanks for the reminder to keep checking this), pressuring it just right I can get the voltage up to 5.07V.

I was going to replace the connector with trifurcon when my crimper I ordered arrives anyway, but the way I played and torqued with J101 made me suspect the header and pressing the wires in better didn't really change. So I pulled the board and replaced the header. This board has some pretty ugly soldering work on it.

But interesting is that it looks like someone tried to do the voltage boost trick on the regulator. But what is going on here? Why 2 series diodes rather than a resistor? Does that do the same thing? Or was this someone reversing the hack, pulling the resistor and putting in diodes instead? The other oddity is I'm not sure this is effective anyway, because this board seems to have the path to ground still on the front side via C9. Should I cut that trace to allow this boost trick to work?

LM323K (resized).jpg

Before putting the board back, I was hoping to get some thoughts on these other changes, and whether I should try to finish it or leave it or what.

There was definitely tarnish, and very ugly solder on the underside.

Also, forgot to mention, if I didn't start any game until after 5 minutes, letting the voltage rise, there were no resets at all.

But what about the trace to C9 that pinwiki mentions?

Well, I fixed the 5V. It boots to 5.05V right away now after changing header and connector, doing some other relevant resoldering and swapping C4 to 470uf.

But, I read some other advice, to always jumper BR2 to C5 because of ... traces ... solder... blah blah. So I did. Except I didn't. I jumpered to C11 right next to it instead. Argh. Now I get to test what I wrecked for 12V! Anyone know what this would do?

I'm getting the Check F114 / F115 Fuses error on boot up now.

It appears from the on board test procedure BR1 is fully open. Blah, made a simple fix more difficult. Should have stuck to just doing the header and connector!

I have to order parts. Any thoughts on if it is just BR1, or what else should I order as a precaution? Hate to replace BR1 and find something else broken too, only to order again.

Unfortunately, I verified all the 12V LEDs are out and the TPs are each under 1V. Seems something happened right at power entry to the board. I don't understand why that harmed the bridge, but the readings indicate it's open from all positions.

I have a new bridge on the way.

My bridge arrived today, and I installed it. But that did not solve the problem, even replaced the caps for good measure. Nope, same thing. I finally tried to figure out by theory what I might have wrecked by the previous misswiring. As mentioned I jumpered BR2 to C11 instead of C5. But the polarity was not mismatched at least. I just assumed when I re-installed and 12V was all out, and saw that mistake, I must have blown out the 12V. But now I checked the schematics, and C11 isn't even in the 12V chain. I was stumped for a bit, but finally just tried to trace the incoming 12V power. The very first step from J101 to F114 didn't have continuity.

When I installed the header, I somehow lost continuity to the fuse. I still don't know how or why, everything looks good. I re-soldered a couple of times, but couldn't get continuity. I finally gave up and just jumpered the pins to the fuse. Re-installed the board and everything is fine.

Oh well, at least I improved my board work and debugging skills. Next time, just basic tracing of steps and check schematics, rather than make assumptions!

I think what threw me off the first time, I looked rather quickly and checked the cap nearest to the bridge, saw it was C5 and went ahead. But that "C5" referred to the lower cap, not the upper, which was labelled above as C11. Need to measure twice and cut once next time.

Do you put the jumpers in only if you are changing the related components? I replaced BR1, C7, C8, and did one jumper from BR1+ to one of caps that hole didn't look completely intact. That's a nice reference pic, thanks. I'm selling this machine to someone new to pinball and am considering adding those other jumpers, if this is good general bullet-proofing that might save some future trouble?

I'm going to look for some 1mm threw holes too, sounds like good to have on hand for this.