Bram Stoker's Dracula
Williams, 1993Since i've put LED in my BSD i'm having problems with all the opto's in my pin.
At the test report it says: check switch 51, 53, 54, 55 and 56. As far as I know its in the same row at the switch board?? Does somebody know what to do and where I can find that problem?
Greets from Holland.
Then on your power driver board, check TP1 to ground (left top corner of board). That should be 12 volts, but if it is 10 volts or less, it can make your optos continuously record even though nothing is passing through the Infrared beam. If 12 volts is low at TP1, you'll need to change BR5.
I can say that LEDs usually do not trip optos. When I was debugging an opto issue once, I used a flash light. That worked as an opto transmitter. But my led flash light did not. Further, I always led all my machines as well as add several led spotlights. This never triggers optos. I think your issue lies elsewhere.
Thnx guys.
I'll start with pulling the LED's out. Thats the easiest way!
Already bought a multimeter because I think the problem is elsewere.
Like I said, All opto's don't work and I dont think that it's a coincident that they are in the same row at the switch matrix...
The only problem is that I cant 'translate' the switch matrix on paper to the PCB. (Wich PCB)
I still have to learn a lot about the pinball electronics... But I'll figure it out!
Not yet. :'(
Pulled the LED's out but thats not the problem and all the glass fuses are intact.
Right now I'm doin a crash course electrical engeneering for myself and try to understand how all these circuits work.
Maybe you can give me an answer what an '(A)'means at the switch test?
If you don't understand what I mean I can make a picture of the DMD whem í'm back from work.
I'ts much easier than explaining in pidgin English.
All the optos you are having problems with should say closed in switch test. It means the switch or opto in your case is active (a). They should not be. Something is triggering them to stay on. None of your opto switches you have listed shoudld have an (a) next to it.
So if I get it right. If a ball gets between the sender- and receiver- opto the switch should be opened and if the ball shoots out, the switch should be closed...
In my BSD it's the other way around. Then the theory of a LED(lightbeam) interrupting the opto shouldn't be possible..., right?
To test the go to the switch edge test. Activate the switch by passing something in front of it. The switches that are not activated will be solid blocks in the switch test. (opposite from normal switches ).
Look for 12v on the opto board, a led should be lighted ( under the playfield ) - fuses 114 & 115.
Take off column and row connections ( while in the switch test) to the cpu and see if the prob changes. If so reconnect and remove connections from opto board.
Check all diodes on opto board.
Replace all LM339 chips
Did the test like justjoe said. The opto's that having problems don't react at all. Other opto's do react.
The (red) led on the opto board lights. So the board is ok. I checked the resistors with the multimeter and encountered that none of the blue ones worked but they were al quite warm. Could it be that all the blue resistors are defect?
Go to your power driver board, check TP1 to ground (left top corner of board). That should be 12 volts, but if it is 10 volts or less, it can make all of your optos continuously record even though nothing is passing through the Infrared beam. If 12 volts is low at TP1, you'll need to change BR5.
Most of the time the blue resistors are fine. To test the optos remove each connection ( going to the optos from the opto board ) and test for 12v. Usually black and gray wires go to the transmitter LED and the orange and gray go to the receiver.
Another way to see the transmitters infrared is to look at them with a digital camera.
You also can test the switches is to tape the transmitters with elec tape and shine a light into the receiver. The switch test should be on when you do this.
* If your switches are the same in the column or row your problem is not the optos themselves. It would be rare if it blew all them at once.
A common problem with the switch matrix and optos is the U20 on your cpu. I believe I have a few of those left (although you may have a few more columns not working with this problem).
I will check my diagrams to see if I can see some areas for you to check before you start replacing parts.
I worked on 7 WPC machines that had the 12 volts low at TP1 on the power driver board. Check that before looking elsewhere. Low 12 volts even caused my flippers to act very weak as well as all the opto switches were stuck on during the switch test.
Aargh !
TP1 gives 13,5v.
Checked the opto's with a camera. They work fine.
I can't find the u20 on the cpu board. The last CPU i can find is U19...but is there something to see if U20 is not working?
I guess Dracula is testing me!
99,9% chance the U20 isn't working.
Iv'e been to a gameroom last weekend and explained the problem. When you cause a short circuit this happens more often. To be sure we will put my CPU board in another BSD and see what happens. If we have the same problem it's the U20 and not a wire breakage. A wire breakage is unlikely because all opto's have an own wire. These 2 failures are my only options as far as I know.
U20 is for columns. If U20 is defective, an entire column of switches will be out. If any of the switches in the column works, your issue should not be related to U20. If you are having row problems, those are U18 (first 4 rows) or U19 (second 4 rows). U19 would control row 50. (51, 52, 53, 54, etc). Again, the same thing applies here. If 51, 52, 53 are out but 54 works, then U19 is fine.
Have you disconnected your switch inputs on the CPU board and tested with a jumper wire yet? That will isolate your CPU board. You can test each and every switch in the switch edge test with a single jumper wire. This procedure is very well explained here http://www.pinwiki.com/wiki/index.php?title=Williams_WPC#Switch_Problems
Scroll down to this: 4.13.2 "Switch Matrix Problems" and follow along. Do those things and report back.
After we get that information above, then we can offer further advice regarding CPU board repair vs wiring, power, and switch repair.
Quoted from the_don:Thnx Markmon, the url you send will really help. (tought I sorted it out)
Homepin, As far as I know the opto board is only there for the sending opto's. These ones work fine.
I'm not quite sure what you mean there? The 10 opto board has 10 circuits on it and it connects to 10 TX as well as 10 RX optos.
Quoted from the_don:Hmm.. I was told this board was just for the sending opto's...
So the problem could also be there. I will check that as well. thnx.
Good idea - this board actually does give a bit of trouble. First thing to look for is the electro capacitor as it can leak and cause issues and then there are 3 x LM339's - and we all know how reliable they are.…..........
Actually I will second the likeliness of the 10 opto board to be the issue. First run the switch tests then if it shows it's not the CPU board then I'd start at the opto board next. You can buy replacement boards cheap if you're not good with soldering.
Quoted from markmon:Actually I will second the likeliness of the 10 opto board to be the issue. First run the switch tests then if it shows it's not the CPU board then I'd start at the opto board next. You can buy replacement boards cheap if you're not good with soldering.
or even build it yourself if the one in the machine is too far gone:
Quoted from the_don:Haha, looks like a challenge! Hopefully it's not necessary.
Most times change the electro and maybe a dud IC and it's away again.
Not worth checking and you can't tell by looking - they only cost a dollar or so - just replace it. It is a VERY common problem on this era of MPU.
take a close looks for burned connectors/pins on the opto board mounted under the playfield. this board controls all but one opto (long range mag opto). might have to replaced the male pin, and re-pinned the female connector with .156 molex. reseat and wiggle it first. restart a game.
Quoted from the_don:Just took the CPU-board out to test connections.
The U20 'looks' just fine, does anyone knows how to isolate and check the U20 (with a jump wire)?
Looks like you completely ignored my post above from last week. Not only did I explain what u20 does but I gave you a link on how to test your switch matrix. I guess I wasted my time typing all that in 
Markmon,
I'm sorry, but thats not how it went. I actually dit that test, but because I don't know a lot about elektrical circuits etc. I wasn't quite sure if I dit the test the right way.
I also don't like to create another failure by making a wrong connection...referring to my lack of skills.
Because I was already asked to bring the CPU to the gameroom, that seemed to be the best thing to do next.
Maybe I'm a slow starter, but I already learned something about the connections. So don't see it as a waste of time...
Quoted from the_don:Markmon,
I'm sorry, but thats not how it went. I actually dit that test, but because I don't know a lot about elektrical circuits etc. I wasn't quite sure if I dit the test the right way.
I also don't like to create another failure by making a wrong connection...referring to my lack of skills.
Because I was already asked to bring the CPU to the gameroom, that seemed to be the best thing to do next.
Maybe I'm a slow starter, but I already learned something about the connections. So don't see it as a waste of time...
Your question was about how to test U20 with a jump wire. My response above at the top of this thread links you to a pinwiki site that talks about how to do exactly this. So I'm not sure how I could have perceived this any other way. Again, I also explained that U20 is for columns. Is the whole column out in the switch test menu?
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Hensbroek
Hopkins, MN
Malmoe