The Aussie Pinball Arcade
Aussie Pinball Forums => Technical Matters => Pinball Repairs / Problems & Assistance => Topic started by: Agentbarry on August 27, 2014, 12:32:10 PM
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Hi guys,
recently my WH20 has started to randomaly reset its self during gameplay. sometimes it can last 10 mins and other times it will only last 1 min.
i really dont know where to begin looking, could this be a bad ROM?
Cheers
Allan
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First thoughts would be a bad bridge rectifier BR2
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Connectors or rebuild the power supply section of the power driver board.
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J101 and J102 connectors - far right hand side of the largest green board of the backbaox.
With the machine off, unplug them and plug them back in again a few times.
This is usually only a temporary* fix and you will probably need to do some further investigating to narrow down the actual cause.
*Based on firsthand experience, temporary being anywhere from one minute to one year. %.%
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Taken from the old pinrepair guides......
Bridge rectifiers or diodes (and their corresponding filter capacitor) convert AC
voltage to smooth DC voltage. This is very important, as all the circuit boards run on
DC voltage. If a game plays fine, but randomly resets, often the bridge rectifier BR2 (or
diodes) and its filter capacitor and J101/J129 connector are over stressed and need
replacement.
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Thanks for all the info guys, I will check it out and will keep you posted
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J101 and J102 connectors - far right hand side of the largest green board of the backbox.
With the machine off, unplug them and plug them back in again a few times.
+1 - I found with my WPC machines that this more often than not was the issue and not the bridge rectifiers. I replaced the headers and connectors and the problem was solved. I would suggest starting at the connectors first, then if its still resetting start looking at the BR's.
'Parts wise' the BR's are easier to obtain (Jaycar etc) and don't require any special tools (ie crimper's) - so perhaps this is why they tend to get done first. !@#
Andy
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Capacitors have a "useful life" of 10 years. BRs should last longer, but the history of these boards developing faults in the future has the "shotgun" approach of replacing all BRs and Capacitors done at the same time in one repair session. A faulty BR will blow a fuse. A leaky capacitor can contribute to a reset.
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Yesterday arvo i had a bit of a play around, the first thing i tryed was just reseating J101 J102. After doing that i turned it back on and it played fine.. has not reset once since.
I have ordered the replacement caps from RS and got some BR from alrtonics. Even though it is playing fine now i still think im going to go ahead and replace all the caps at least
Thanks for all the help guys!
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It would be well worth your while replacing the header pins on J101 as well as replacing the actual connector. if that is what was playing up, you may as well tidy it up whilst you have the board out doing the other work. At bare minimum, reflow the solder joints, every chance they will be cracked.
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The fault came back yesterday and am waiting on the 15kuf caps to do the job
I got a good laugh though, my housemate was playing the machine and was having a great game. Completed whirlpool challenge, got to class 6 river, wet willies round 2 collected. all leading up to a nice vacation jackpot. he hit it, it does its usual thing of looking like its dead..... Reset just at the time the screen goes blank.
good old machine stoped my housemate from setting any more high scores hahaha
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Be very VERY careful replacing the bridges and caps as they are a tight fit in the PCB holes and the plating used in the plated through holes in those days was nowhere near as good as todays technology.
You run a very high risk of 'pulling out' the plated through hole and thus losing the connection between the top and bottom traces.
Make sure you check the finished job using a mulitimeter on continuity and use wire links if you need to to ensure all connections are sound or you run the risk of having a board with many more faults than when you started.
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Cheers for the heads up, i pulled the board out yesterday to find that someone has done this before me but only replaced 4 out of the 5 15kufd caps.
the attached photo is before i did any work and as you can see they had exactly the problem you were talking about.
Turns out i was an idiot and ordered the wrong bridge rectifiers, i did not realise they are a wire leg and not a spade leg ><
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Looks pretty ugly!! It is possible this existing work is adding to your reset problem. Make sure to clean off all that old flux. Isopropyl alcohol or circuit board spray cleaner from Jaycar and small a brush is good for this. Also as suggested before, use a multimeter to bell out the tracks when finished. I found taking a photo of the board with the components removed is a good way to remember where the tracks go. The large caps cover the tracks and could leave you guessing what's connected to what.
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It is also possible a previous owner had a reset issue and has replace these components which has just patched up the real problem. I would be wise to check the whole power train from transformer through the driver board to the CPU.
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I will just throw this out there as i had the same issue with my WH2O resetting.
Most people would think this is a no brainer silly mistake &^& but i never thought the screws that hold the board in place actually earthed the board... i thought they were just to rest the board on... it was only after multiple pages of reading on this site someone said " tightened the screws and has good earth"..... Bingo.... tightened the screws and no re sets ever since..... may be your case too... screws come loose and its not a random reset its just when the board looses the earth and turns off.
Hope this helps
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+1 to tightening the screws on the boards. I had issues years ago with a machine that kept on losing sound. It would fade out and then come back and fade out again. Ended up being a lose screw on the power driver board.
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Cheers for all the ideas, i left the machine doing a auto burnin and no resets yet, will see if the fault comes back
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I've been fixing a great deal of WPC boards as of late.
In my experience, resets are most often caused by cold solder joints or connectors.
You would be amazed at how much the +5 volt supply will come up by doing some simple things. Removing the solder on the 2 legs of Q1 and resoldering. Resoldering the legs of BR2. Resoldering C4 and C5. Resoldering J101 and F113. Note that I didn't say *reflow*, I said *replace*.
I've removed all the caps on a WPC driver board, and thrown them on my cap tester. On many 20 year old WPC driver boards, the caps are all fine.
There are some where the caps and bridges do fail. But, those are a whole lot less common.
The whole 'replace BR2 and C5' thing has worked for so many people because when they replace BR2 and C5... they remove the solder, and replace it.
I've fixed my fair share of boards, too, where someone took the 'replace all the bridges and caps' method, and managed to run a whole bunch of plated through traces. They ended up spending twice as much as they would've, if they'd just sent the boards out to begin with.
Don't get me wrong, we all learn somewhere. But I try to convince people to solder on some old junk boards before diving into pinball boards. Mess up an old alarm clock or something, learn, and them apply what you've learned to your pinballs :)
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I agree with John above - i am no expert on this stuff, but have been doing quite a few repairs on the possum pins and a few for mates around town. Most reset issues i have come across are header pins that need to be replaced, then resoldering components. I have no way of testing caps,so cant say if the ones i replaced needed replacing, but i think only once have i had a bridge fail.
Of course the counter argument is that since you have the board out, why not replace all components that have potentially reached their lifespan...i will do that if i am doing repairs for someone else, but for my own, i'm happy to leave them and repair when required.
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the fault has not come back in the last week and its been getting played quite a bit. i dont think the caps were bad, i do think that the solder was the main cause of all the problems
fingers crossed it stays working
Thanks again to everyone for all the help
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Great that it seems to be cured.
A couple of points that this thread has raised. One is tightening of the mounting/earthing screws. This is not only a good idea but is actually required in Zacs. I had a buyer of a Zac MPU say it had worked fine for a year but suddenly started going beserk and blowing fuses. Naturally the first thing that the finger gets pointed at is the replacement MPU ^.^.
Turned out to be loose PCB mounting screws on the power supply PCB causing the random problems and fuse blowing.
The second point is RoHS (Removal of Hazardous Substances) or "lead free solder". Thanks primarily to Europe, practically all new electronics for the past 10 years has been made using this hideous stuff. That coincides with a drastic drop in the reliability of almost all electronics from TVs to Pinball machines.
This will get worse and quickly as RoHS solder ages poorly and seems to break up after just a few years creating dry joints that simply cannot be corrected on some of the microscopic parts used these days.
Be aware that this RoHS issue WILL affect new pinball machines probably about NOW!!!
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I'm a noob at pin repair but have been doing bench repairs/ service to varied ewuipment for a long time. I'm sure other techs with more pin experience have given good advice.
Reseating board connectors has worked in the last three pins I've seen with resetting issues.
This work is also done when replacing bridge rectifiers.
I agree with Mike, lead free solder is problematic and I just don't seem to get off on the fumes as much! ;-) Z