I just joined the club last week. Such a great game. It is actually the first game in our lineup that my wife wants to play together.

I would say that is is working about 98%. There are one or 2 lamps out and I am not sure if some of the switches are working. In order to check these out further, I need to get the self-test to work.

When I hit the self test button, I can hear a click under the play field and then everything but the GI goes dead. Not sure where to start on this. My thought is maybe a solenoid is shorting and killing the MPU???? Anyone run into this before or have an idea of where I can start?

Thanks Chalkey. The rectifier is integrated to the wiring harness via wire nuts (not by me). Looking through that spaghetti is not going to be fun.

I will try unplugging connectors to see if I can get into test mode. That should at least narrow the options

I am fairly certain the switch works. It goes into self test, but the first step in the test is causing the boards to shut down everything. The GI is the only thing that will continue to run

OK, got home and tried things out. Looks like the self test does work, but I may, indeed, need a new switch. It appears that sometimes a single push of the switch would register twice.

I was worried that I may have some switches not registering, but they all seem to work. One interesting thing is that I have to press the switch down for a second or more for it to register in self-test, but it does register fine in game play.

Th knocker doesn't work. It appears to be connected, but it never fires. I did not put the meter on it to see if it gets voltage or not. My daughter hates the cabinet knockers, so this is low on the list.

I have a few bulbs out. There does not seem to be a lamp matrix chart. I can't really make out the list in the schematics to a chart. Does anyone know if a lamp matrix chart exists, and if so point me in the right direction?

So instead of a matrix, each lamp is controlled by it's own connection wire and circuit?

It looks like I have 10 lights out. (I metered the sockets and no power goes to them during lamp test)

J3-1
J1-1
J1-8
J3-19
J1-28
J2-4
j3-16
J3-23
J2-8

The last one is Advance Loop Value 1 from the bottom drop target, but I can not match that up to a description on the list.

I found that Q48 is missing and there is a burn spot in it's place. That maps to J3-16, so that makes sense.

The transistors are almost flush to the board so trying to get a logic probe on the legs while the board is in the machine is going to be near impossible.

Doesn't look like I have the transistors or thermistors handy. Just placed an order for some replacements. I'll post back when I can change these out.

I also ordered some molex connectors to get rid of the wire nuts.

Working on doing some diag on the lamp board while I wait for the new transistors to show up. Schematics tell me that a lamp that is not working leads back to Q37. Q37 is testing good (while on the board which I know is not 100% accurate). Assuming Q37 is good, I am looking up stream. It looks like it leads to resistor R37 and that resistor leads to U3. I have a problem there. The schematic shows the connection going to pin 5/6. I am not sure how to read this. Should I be testing pin 5, pin 6, pin 5 and and 6? How do I read this?

SeaWitch Diagram Chip Pins (resized).jpg

Thank you all for your replies. I appreciate all the help.

No, I haven't been back under the playfield. Just trying to take a look at 1 of the obvious ones.

This still sounds weird to me, but if pin 6 is the one to test, I will just ignore the 5.

found a video on testing the Stern/Bally lamp boards. Put the multi-meter in diode mode, assuming the flat face of the SCR is facing you, put the red lead on the center pin and the black lead on the left pin. A reading of around .6 would indicate the SCR is OK.

I did this on all the SRC's. It did show 1 of the SCR's as not OK, and I was able to track that down to one of lamps that was out. All the others tested good, so I still have 8 I need to figure out.

The chip may be working just fine. I am just trying to find the signal and trace it through. If I don't find the signal at pin 6 then I need to go further upstream.

Thanks @quench! It may be a day or 2 before I can try that out, but this is great information. The MCR's are soldered very close to the board, not sure I can get to the pins reliably, but I will see what I can do.