The only way you can get a partial row or column failure is a wiring problem under the playfield. The switches before the problem will work and the switches after the problem will not work since they're daisy-chained. Use switch diagnostics while following the wire downstream and closing each switch (remember the manual will give you the wire color) until you find the point where the switches quit working.

Somewhere between the non-working switch and the last working switch the wire is broken or there's a bad connection. The usual problem is a wire has become broken at the solder joint on the switch, which can often look like it's still connected so you should gently tug any suspect wires.

Don't forget that a wire can break internally. If you can't find it visually, you'll need to use a DMM to check continuity.

Do you have a meter?

Did you run the built in diagnostic switch test first?

Read on how to check a diode.

Remember the wires are daisy chained from one to the next. Start with the switch before the bad ones.

Yea vid1900 is spot on here. Each of those switches share a column wire. A meter in continuity mode will beep when you touch the leads. It should also beep when you touch the two of the column blades on the switches. So test each switch on the column starting from a working one. Find which one beeps and which doesn't. When you find one that doesn't beep trace the wire and you should find the break.

If you were messing with the target bank, look if you bent a nearby diode so that it is making contact with some other connection.

Look for a cracked diode too. Give 'em all a little tug.

So if it were anyone else, I would say no way to this. But you know more than I do so I'll ask as a question. So how could a cracked or bent diode cause the rest of the column to be out? I can see it causing more switches to be *on* but not dead / off.

The matrix strobes each column in sequence, pulling down column 1 and checking all of the rows, then strobes column 2 while checking all of the rows, and so on. This sensing happens at a rate of 500 reads per second.

By cycling through each column sequentially, the system can differentiate between the switches in each column while the rows are separated by the blocking diodes. If a diode is shorted, or has been installed incorrectly, the system will get confused since the isolation between switches no longer exists.

Very cool. Thank you.

Something is not right there. You should not get the same readings in both directions on the switch diodes. Can you borrow a meter with a diode test function?

Testing a Blade/Leaf Switch's Diode.
Testing the diode on a leaf switch is far easier. No wires need to be disconnected, and the switch should not be activated. This technique assumes the switch is wired in the standard configuration: green (ground) wire to the center lug, the banded end of the diode solo, and the non-banded diode lead and the switch wire(s) to the other switch lug (as shown in the pictures below).

Leave the leaf switch's diode and all wires connected.
Make sure the switch isn't activated.
Put your DMM on diode setting.
Connect the black lead of your DMM to the diode's banded side, and the red lead to the non-banded side.
You should get a reading of .4 to .6 on the meter.
Reverse the DMM's leads (red lead to the diode's banded side). You should get a null meter reading.

Simple solution: kill 2 birds with one stone - sleep at work.

Keith, I gotta admit, I probably would too, if you were my surgeon. but if you told me why, I would understand.
Seriously though, is it coincidence that the diode on switches #33,34,35 all burnt at the same time?

Wow, small world, I live in new castle now, but graduated from Wilmington Area, then attended westminster.
Is your meter on diode setting, 'cause I don't get those readings either. it should be just like wayout said .4-.6 one way, null or 0 reading the other. Anyway, keep us posted on what your guru has to say.

I'm having a similar issue with a Williams 11a machine. When I test the switch diode (outlane) its tests bad, unless the switch is activated, then it tests good. All the inlane switches diodes test the same this way. if you disconnect the diode, its test good.

The difference of testing is what to expect when the switch is activated vs. not activated. The test is different if you are testing a microswitch vs. a leaf switch, and I have highlighted the step where it is different between each below:

Testing a Microswitch's Diode, without removal.
You can test the diode on a microswitch without unsoldering a diode lead from the switch. This technique assumes the switch is wired in the standard configuration: green (ground) wire to the center lug, the banded end of the diode to the far switch lug, and the non-banded diode lead and the switch wire(s) to the close switch lug (as shown in the pictures above).
Disconnect the middle green (ground) wire from the switch. It should have a quick connector. If the middle green ground wire is soldered to the switch, ignore this test and do the above "fail-safe" diode test.
Put your DMM on diode setting.
Connect the black lead of your DMM to the diode's banded side, and the red lead to the non-banded side.
>>>>>>>>>>>>>>>Activate the switch.<<<<<<<<<<<<<<<<
You should get a reading of .4 to .6 on the meter.
Reverse the DMM's leads (red lead to the diode's banded side), and keep the switch activated. You should get a null meter reading.

Testing a Blade/Leaf Switch's Diode.
Testing the diode on a leaf switch is far easier. No wires need to be disconnected, and the switch should not be activated. This technique assumes the switch is wired in the standard configuration: green (ground) wire to the center lug, the banded end of the diode solo, and the non-banded diode lead and the switch wire(s) to the other switch lug (as shown in the pictures below).
Leave the leaf switch's diode and all wires connected.
>>>>>>>>>>>>>Make sure the switch isn't activated.<<<<<<<<<<<<<<
Put your DMM on diode setting.
Connect the black lead of your DMM to the diode's banded side, and the red lead to the non-banded side.
You should get a reading of .4 to .6 on the meter.
Reverse the DMM's leads (red lead to the diode's banded side). You should get a null meter reading.

Hey wayout-
That is some good info about the micro vs. the leaf diode check, is that because the micro is a NC switch? And is Imeh's outlane switch on his system 11 a micro or a leaf?

They are micro switches. All connections are soldered. I,m sorry but what is the fail-safe method you are referring to ?

Fail-Safe Diode Test.
With the game off, use your DMM set to diode position. With the black lead on the banded side of the diode, you should get a .4 to .6 volt reading. Reverse the leads, and get a null reading. If the diode test bad, cut one lead of the diode from the switch to remove it from the circuit, and test it again just to make sure the diode is really bad. Reconnect the diode after testing, or replace it if bad.

Ok, that is what I did. When wired to micro switch, it reads bad unless switch is activated, but when it is disconnected it reads good. I assume this means it is good?

There is either a break or a bad connection on your green black wire between 35 and 36. If the diode is bad it will only effect the one switch. Electricity is just like a blood vessel, it flows until there is a clog (break in the wire.)

and most always take the path of least resistance.

"Wayout - My DMM has a diode function and I used it. I did get .4 readings on lamp diodes, and a null reading when I reversed the leads, like I should. But when I tried the diodes on all switches, I got null readings in both directions."

That is just wrong. You should really concentrate on the switch issue and really try to do exactly what folks are trying to carefully tell you. As a lot of times you can not test a diode in circuit. With Lamp in parallel with diode you should get a reading in both directions. switches should be the easier of the two. situations. In diode test your meter is outputting a small current and reading the voltage drop or turn on voltage for that diode. DO NOT test diode or ohms with machine on. ONLY Voltage and Amps with machine on.

Funny it seems like a ton of problem start with I put in this aftermarket board and ......

Don't start replacing wiring please. They would consider that a shotgun approach which has good chance of going very wrong.
Try a couple things, take notes and if you feel stressed call it a day and have a drink. Try again the next day.

To me troubleshooting is fun, it is a puzzle. But that is just me. You might just be a player. RELAX

Oh thick smaller number wire can handle more current before melting and thinner higher number wire can handle less current. So 16 gauge is actually thicker than 18 and can handle more current.

I do agree win CNKay, don't replace wiring until you have actually CONFIRMED that there is a missing connection because of that wire. Conductors can break within the insulating jacket, but that is really rare. Usually only with really really old games where that section of wire has been flexed.

A brief story, I have worked a some games and a few of them are Williams sys 11s so I am fairly familiar with switch problems with them. To make a long story short, I was beating my head against the wall for a long time with a switch problem with F-14 Tomcat before I solved it forever. I had a target that would suddenly give me game startup or switch test error. I went 'round and 'round with this. It was intemittent and would work fine for weeks and then would begin to fail. Usually when I had guests over. I had already replaced the diode. I had already check and replaced other diodes and wiring. Eventually I pulled the target out itself. The stupid contacts were registering a short with my meter out of the game. There was no rhyme or reason for it - I wanted to dissasemble the target and fix it. Unfortunately, the target switch contacts are separated by nonconductive plates and the whole mess is riveted. I ordered a new target switch, installed it, and it has been 100% perfectly operational since.

I am not saying this is your problem. I am merely saying you need to have a lot of patience, troubleshoot the heck out of the machine before you give up, and weird s%@! happens to all of us at times. It may be hard to troubleshoot your game when you are right there next to it, but for us folks helping others online who are not with your game it's that much harder. Don't part it out, hang in there...converse with folks and eventually it will get solved. A switch error is no reason to scrap a pin.

OK so from your original post it sounds like you are having issue with 4 Target, Right outside rollover and E rollover.

Look on pinwiki: http://www.pinwiki.com/wiki/index.php?title=Williams_System_3_-_7#Switches

Well, that does make some good sense that the other columns are out. As it is a new board, it should work. Start by unplugging everything on the board. Then get the manual, turn to the schematics page in the back that shows where the wires are supposed to be plugged in, and then plug everything back in. Let's assume that something didn't get plugged in properly before we start assuming that there is something wrong with the board. (There might be something wrong with the board, but let's not start there.)

Those are all caps the little yellow things. all marked like C104 C103. NOT resistors.

Don't remember know what the heck i posted. Well yes to test diodes across coils, you have to take at least one end off. And well it depends where they are in circuit whether need to be tested out of circuit. Williams have a diode across each switch. So to test any diode. Put meter in diode function place Red lead on non banded side and Blk lead on banded side. You will normally get reading of .6-.7 volts. If you reverse leads you should get nothing or OL on meter. If meter beeps reads like .002 or something diode is bad. OR OL both directions.

Also for switch issues make sure you did not short switches during blub replacement and such.

I don't believe I knew it was a new board, I can't help at all as I don't know about them and have no schematic.