Got other machines you can swap driver and cpu boards with?

In my expedience albeit a short one..LM323K seldom go bad. I would look elsewhere..is there a Z connector on the game? Sorry I'm not home or else I'd look at my NF. Also if you say the last owner screwed up the eyelets make sure you have a good connection and solder work at C5 and the BRs. Lastly, the Dmd controller sometimes prevents the game from booting..make sure all cabling and wiring is good there also.

try swapping the ribbon cables with the WCS.

Likely the machine is resetting because the voltage at the MPU board is 4.84 volts or lower. Good chance the game may not even boot up with 4.7 volts from my experience.

This is good to know, but now you need to measure across the blue capacitor on the MPU board. If you see it measure >.7 difference than the TP2 on the driver board compared to the blue capacitor, try just reseating J114 on the driver board and the MPU power connector at J210, then measure the voltage again. I suspect your voltage will rise back up close to what you measured at TP2. There is a good chance that may work for a while, but it acts up again, I would repin J210. And if it craps again, repin J114. Also inspect the pins on J101 for any burnt pins as well.

If reseating the J210, J114, and/or J101 seems to solve your problem, it will be of great benefit to repin these female connectors and replace the male pins on the board if they look tarnished.

You want to buy the "WPC Power Fix Daughterboard" from here:

http://kahr.us/

I just installed one on a No Fear that had resetting problems. That cured it.

Good bet you have a filter capacitor problem and excessive ripple on the DC side. Got a 'scope to see how dirty the various V+ buses are? If you don't find someone who does and have a look.

You can pull your hair out for a *long* time with what appears to be good voltages on a DMM yet in fact they're crap.

http://www.ezsbc.com/index.php/featured-products-list-home-page/psu5.html#.V1EQUr4giUk

Do yourself a favor and try these, it has an adjustable voltage pot on it, set all my games to 5.10, of course changed the caps and BR's and all the pinwiki troubleshoot tips, resets are gone! These made a huge difference, many games were still reading 4.88 give or take, not any more.

These do not fix all resets. I bought one for a bsd I had with a reset issue, It made the reset worst. When I emailed him and asked about it making the reset worst I got an email looked to be a default made up just for people with a ?. It said something like this board/pcb is not a miracle board so it will not fix ever rest issue on a wpc game. Its been a year or more but let me see if I can dig up the email.

Anyone know his email address I can search for it then.

I had games resetting at random, did the pinwiki guide, new ribbon cables, Daughter boards, 2 stacked voltage regulators maintaining 120, nothing worked until I installed the product I listed for you, I was then able to adjust the pot and raise it to a level of over 5V, And my resets were gone, I put one in every WPC game I have, does not even require the heat sink any longer. And you can get 3 of them for the price of one daughterboard.

The blue capacitor (normally on most MPU boards anyway) is C31 that I mentioned.

Good. Now it seems resistance built up so much on J210 and/or J114 that it should be easy to see once you repin J210 if it helps or not.

Mate do your self a favour. Replace the Header pins on the Power driver board and the CPU board. J210 and J114. Chuck away the Insulation displacement connectors on the cables attached to those headers and repin them using Truficon connectors.
No amount of resetting will correct worn out connectors that have lost their tension over time, in fact the more you pull them in and out the less tension they will maintain and as you have seen the problem is becoming worse.
The high resistance joints these old connectors cause will be enough to drop the voltage low enough to trigger U10 MC34064 under voltage sensing circuit on the MPU board.

Well said. Include J101 in this list to repin as well. 5 volts comes in the driver board through this connector.

As c_mario stated, if you haven't changed all the connectors, you're throwing darts. Change everything from the two red wires on the transformer connector up to the driver board, and then the connector from the driver board to the CPU. Change the header pins too, on the driver board (AC in and DC out) and the CPU. 9 out of 10 times this takes care of resets.

I've fixed resets on games that were using the Kahr reset boards. The Kahr board worked for a while, then resets started again. Why? Because the connectors and header pins were the actual problem. The Kahr board is fine if your issue is caps, bridge, or the regulator. They aren't a good solution if the problem is connectors. And since the problem is usually the connectors...

Games that have reset issues I do the following in this order. Typically the games I do are someone else's and I don't want to have to go back to pull boards out again.

Replace J101 header and connectors
Replace J102 header and connectors
Replace J114 header and connectors
Eliminate or replace J114 Z-connector to CPU
Replace C4
Replace BR2
Replace C5
Jumpers between BR2 and C5
Put driver board back in and measure voltage at TP2. If its around 4.95V or above you are probably good to go. If not, I replace with an EzSBC LM323K adjustable voltage regulator.

Pretty much guarantee to within 99% that your resets will be gone (outside bad thermistor or several other non PDB components).

You need to see both voltage (which you can do with a DMM) and *noise* (any AC component in said voltage), which you cannot see with a DMM. DC logic (e.g. the CPU) needs *clean* DC power to work properly. An AC component of materiality can and *will* cause a watchdog that is voltage-triggered to fire, and bang -- there's your reset.

If you just want to throw parts at the problem you'll probably fix it (eventually) but IMHO that's the wrong approach. Are IDC connectors less than ideal? Yeah, they are, and any connector has only so many cycles before it degrades (the ones used in this sort of application have rated mate/unmate cycle lives in the tens or hundreds, *not* large numbers of cycles, as they're not intended to be routinely plugged and unplugged) but unless you like unnecessary work it's IMHO crazy to just chase these problems with parts. It would be nice if pins were assembled with high-quality crimped-pin connectors as they're clearly superior, especially in a vibration-prone environment, but they're not (and if they were then you'd have to own the correct crimper to make quality wiring repairs, and the proper crimpers designed by the manufacturers of those connectors are *not* cheap.)

I would remove the CPU board and examine it closely under magnification to see if you can detect any sort of problem with the solder joints around the connectors. Those sort of problems are common; I had a DMD that was flaky on my Apollo 13 which proved up to be a bad connection at the header on the DMD power board. But if you've already checked those visually then out comes the 'scope and start looking at the power. If you find noise you work your way back until you find the source (the point beyond which it's clean) or you get to the filter cap; on the other side should be CLEAN rectified but not filtered DC (if so then you replace the filter cap.) Beyond the bridge should be *clean* AC. If you have a bad connector then replace it but first know where the problem is rather than scatter-shot changing out parts.

The fewer times you have to rework a PC board the better; changing out parts on one for grins and giggles is IMHO a bad idea as there is always a risk of lifting a trace or breaking a through-hole's plating and then you're in for a lot more troubleshooting and work.

Do that. I'd like to see the results. I bet it doesn't reset.

Here's one someone mentioned to me recently that I haven't had time to include in the PinWiki.
Make sure the line voltage fuse connection is solid. Remove the fuse. Sand the conductors and reinstall. Shot in the dark...might work.
--
Chris Hibler - CARGPB #31
http://ChrisHiblerPinball.com/contact
http://webpages.charter.net/chibler/Pinball/index.htm
http://www.PinWiki.com - The Place to go for Pinball Repair Info

Mike....ugly bugly. Trust your part removal technique my friend and lose the jumpers.
--
Chris Hibler - CARGPB #31
http://ChrisHiblerPinball.com/contact
http://webpages.charter.net/chibler/Pinball/index.htm
http://www.PinWiki.com - The Place to go for Pinball Repair Info

subscribing, currently working on a reset problem with my Corvette. Would like to see how this is resolved.

I don't use the jumpers but the last few that I've done had already been 'reworked' by someone else. It's been a while since I've a clean PDB that has never been touched. The last one I've done was just this week and it was heavily reworked. Just about all the bridges and caps were replaced previously. There was not much left of some plated through holes and pads on the 12V circuit and that caused some WEIRD opto issues. I had to run jumpers. Now that I have a nice desoldering station I can remove without damaging traces/pads; but I figured I'd throw that out as most don't and compromised traces/pads will make you pull your hair out.

Favorites for posterity sake.

OP, I am sorry youre going through this. If it is any consolation to you, some of us are paying attention and learning from this so we know what to do down the road.

I'm sure it'll get resolved soon. Hang in there!

isn't the blanking circuit supposed to prevent this type behavior?

This type of board abuse makes me sad

Pay Clay $20 for his pinball ninja website, he covers tons of reset issues with videos. Best money you will spend.

This is where eyelets come into play, I actually never use the stitch method and always eyelet the board since they will outlast the board if installed properly. This is a picture of a board I repaired after someone pulled burned resistors with a soldering gun.
eyelet_repair_(resized).jpg

Did you reflow the solder on the back of j102 yet?

Stiching is fine.

They are expensive; I happened to come across a manufacturer sample kit that contained 10's of thousands of copper board repair eyelets, and since I have all the ball mills, there really is no reason for me to stitch anything.

You really want to check the 5 volts for ripple. While a scope is by far the best method, you can do a poor man's version of testing with a decent meter. Put it on the lowest AC range and measure from 5 volts to ground--cheap meters will give you really wacky readings, like 10 volts for example. If you have another machine you can compare the readings between known good and unknown.

While not as cool as an eyelet press, you can put together the tools to do eyelets for about $50.

http://pinballrehab.com/1-articles/solid-state-repair/board-rework-test/230-repairing-plated-through-holes

I forgot to mention the eyelet insertion equipment

That is kind of an important detail.

I feel your pain, Frax.

My No Fear driver board was hacked also. I just wholesale replaced ALL the bridge rectifiers and related electrolytics, a new LM323K, new J120, J121, J101, J102, J115, and a few others just for the hell of it, among other things.

I have a Pace desoldering station from the 1980's with a complete trace/eyelet/solder pad restoration kit that I use for all my PCB repairs, plus I have the advantage of being trained in PCB rework by TRW/NASA, so I guess I'm lucky in that regard.

terryb is correct. Don't stop at the 5 volts, though. Check the 12 volts that the 5 volts is derived from also. Personally, I check all regulated voltages in the machine. I don't bother much with the unregulated for obvious reasons unless there are fuses blowing.

If you would like, I have a personally scanned copy of the No Fear manual I can send you if you need/want it, and also archived copies of Clay's guide for WPC repair in either PDF or Word format.

I would be happy to share them with you if you have the need or desire. Just send me a PM.

Greg

Based on you mentioning this in your first post

I have no doubt that the driver board is good without you swapping the board. So it is at least making it to the J114 with a solid 5 volts. You are losing some voltage due to resistance through either the J114 female/male and/or J210 female/male connections.

Think of it just like the GI connectors in WPC games. As the resistance builds up on J120 and J121, the voltage to the bulbs gets lower. Thus, whole strings of lights are dim or even completely off depending on which pins are affected.

That would do it.

I was taught the first three steps in troubleshooting are visual inspection, visual inspection and visual inspection. Over the years I would bet I've found 60% of board problems thanks to that advice.

You've got contact adhesion on a few of those pins--not surprising with a solder sucker. Heat them with a soldering iron and use a spudger (wooden dowel with beveled edge) to push them towards the center of the through-hole. Before you remove the socket give it a clockwise and counter-clockwise twist. That should break free any remaining solder.

You really don't want to damage any traces/pads on the ASIC. They're a bitch to fix.

Frax-
You did an excellent job with just a soldapullt. You may want to try some solder wick also, make sure it's got rosin in it to wick up all the remaining solder.

GREAT job.

Greg

Very nice job on the desoldering, I would have never even attempted that without a desoldering station, it's just to big a risk ... especially if its someone else's board