(Topic ID: 171032)

Demolition man Weak coils

By Pesmerga

7 years ago


Topic Heartbeat

Topic Stats

  • 24 posts
  • 6 Pinsiders participating
  • Latest reply 7 years ago by GRUMPY
  • Topic is favorited by 2 Pinsiders

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#1 7 years ago

Hello again got a problem with my demoman pinball all the coils except for the flippers are weak! For example the ball launcher isn't able to drop the ball and if i drop a ball in the upper-right hole the coil is too week to pull it out

I have tested the power board TP points since looking on the web the problem could be here.. these are the results:

TP1=13.3V (should be 12V)
TP2=5V (should be 5V)
TP3=12V (should be 12V)
TP6=68V (should be 50V)
TP7=1V (should be 20V) !!!
TP8=15.3V (should be 18V)

As you can see there are clearly some problems, but I really don't know where to look for the cause!

I have also tested the power on some coils --flippers are 43/45v and the ball launcher 63/64v

What do you think of the results? Any suggestion on what to do?

Thank you!!!!

#2 7 years ago

Well I think you're on the right track, it's power issue. It could be the Bridge Rectifier on the power board. Also try taking off the connectors on the powerboard and put them back, just doing that helped on my Shadow.

#3 7 years ago

Hello kvan99 already tried that way but no changes! :/ today I will try to put on another power board, took from my bride of pinbot, and see what happens!

#4 7 years ago

Ok, is the power board the same...I can't remember BOP is a sys 11, check to make sure you can swap. Worst comes to worst, rebuild the power supply, you need to change C5 and the BR2. I know people will hate me for saying this, but if the game is 15+ yrs old it probably needs those rebuilt anyway.

#5 7 years ago

Changed the power board and now it works greatly!
I have also tested the TP on the working board to see differences and here are the results:

TP1=13.5V (should be 12V)
TP2=5V (should be 5V)
TP3=11.8V (should be 12V)
TP6=68.9V (should be 50V)
TP7=20.5V (should be 20V) ----> as expected this seems to be the major difference
TP8=15.5V (should be 18V) ---> what does this 3A difference means?

now..how to detect the problem on the old power board?
I was thinking to change bridge rectifiers BR3-BR4 cause some friends told me that are usually problematic but i don't really know '^^

any help is accepted!

#6 7 years ago

Try testing the bridge rectifiers with multi meter.

#7 7 years ago
Quoted from Pesmerga:

TP8=15.5V (should be 18V) ---> what does this 3A difference means?

Actually on my Whitewater in attract mode, I see it vary between 15.6v and 17.5 v depending on when all the insert lamps are flashing on. I do not see your 15.5v as an issue. You can put your game in test mode and you'll see the game will not be in attract mode and the TP9 will be higher (mine measures 17.51 volts) and stable since the insert lamps are not putting a load on the driver board.

Quoted from Pesmerga:

TP7=1V (should be 20V) !!!

Definitely an issue. Try testing the bridge rectifier with multi meter just as MotorCityMatt mentioned. Usually though if a bridge rectifier fails, it usually blows a fuse, if one is in the circuit. Did you check all your fuses?

#8 7 years ago

Thank you guys! Which bridge you think I have to test? There are five of them! I guess i'll have to desolder them..but how can I perform a correct test? I'm new to electronic This is my multimeter, which mode should I use? And where do I put the pointer to test the bridge?

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#9 7 years ago

You don't have to desolder them. YouTube is your friend for everything.

#10 7 years ago

Check pinwiki reset info, it has the tests for a bridge. You want 5 ohms across the legs. Pinwiki shows you the four tests to conduct.

#11 7 years ago

Hello guys! I've tested the bridges as suggested on the pinwiki guide! They seems to be all good all the values are around .6 (the working range is from .5 to .7).. Maybe the problem is elsewhere.. I show you some pictures.. Maybe they can be helpful! As you can see someone did some (imho bad) works on it!

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#12 7 years ago

You checked the fuses right?

#13 7 years ago

Sure! They're all ok! I've replaced 1 which was shorter than the others but still worked..

#14 7 years ago

Not much more in that circuit but C11

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5 months later
#15 7 years ago

Hello everyone! I'm back on this topic with news! I have changed c8, c11, BR3 and BR4 but no success! Now the coils don't work at all except for the flippers! Tp6 and tp7 measure 0 and led 5 is always off! Also the flashers are off any suggestion???

#16 7 years ago

U check fuses?

#17 7 years ago
Quoted from Pesmerga:

Tp6 and tp7 measure 0

You broke the thru holes on the board and now there is no continuity from front to back.

#18 7 years ago

Fuses checked. All ok.

Grumpy you're on the good way..i checked the continuity between pin connectors, bridge rec. and capacitors and in some cases there were no connection.

It seems that the solder is not able to pass through the other side of the board and completly cover the bridge legs..
how am i supposed to do? Even adding more solder it doesn't seem to go through! It just stay on one side and form a bad ball shape joint..

#19 7 years ago
Quoted from Pesmerga:

It just stay on one side and form a bad ball shape joint..

You need to remove the solder then add flux and then resolder.

#20 7 years ago

Problem solved! Several traces were off and I recreated them with little pieces of electrical cables. Now everything is great a part of a strange smell of burned plastic! How can I be sure that cables will maintain?

#21 7 years ago

I have found the problem!
Pin 12 of J115 connector (GI) was starting to burn and melt! It doesn't seem to be connected to the previous repaired circuit but what is causing it's burning??? How can I repair this thing? This is an infinite story!!! Thanks for your help!

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#22 7 years ago

Cracked joint makes high resistance which in turn causes high heat. Now you need to replace the connector and the header pins.

#23 7 years ago

I didn't noticed a cracked solder joint here..I hope that once replaced it won't burn again..and also I hope that it is not connected to the previous reparation..any suggestion, advice or warn on replacing connectors?

#24 7 years ago
Quoted from Pesmerga:

advice or warn on replacing connectors?

By the correct tool for inserting the wires in the connectors. Take your time and do a good job.

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