Are any switches registering in the switch test mode?

If you disconnect both J2 (harness to playfield switches) and J3 (cabinet switches) off the MPU board, do the 3 spinner lamps still stay on?

Both the switches and lamps share mostly the same control signals from U10 (6821 PIA) on the MPU board which could explain why both are playing up at the same time.
You could try swapping U10 and U11 since they're both 6821 PIA's. If your PIA in U10 is faulty, it will cause display issues if it's plugged into U11.

Did you try to disconnecting both J2 and J3 (switch harnesses) off the MPU board? This might confirm that you have a short in your switch wiring (which it appears you have).
Do you have a pic showing your flyaway targets pointing to what you were doing with them?

I presume the displays are working ok?
Have you got a logic probe or other means of checking signals on the MPU board?

Oh, in the mean time, are any switches responding in the switch test? If yes which ones?
Also if you completely disconnect the Lamp driver board, do the coin switches then respond?
Just trying to isolate if the issue is wiring or not.

1. I see in your first pic there's been some solder work on the PCB above the flyaway targets. Is that what you were working on when things started going wrong? Have you checked for shorts in the soldering?

2. What are the handful of switches that aren't working on the playfield? This will help to better understand all signal lines that are playing up in the switch matrix.

3. Do those 3 spinner lamps come on immediately when you power on the machine?

4. With the machine OFF and your DMM set to read low resistance, if you remove the 500 spinner lamp from its socket and measure the resistance between the colored wire connected to that socket and ground, what resistance is it measuring? If you compare it to a lamp socket where the lamp isn't lighting up, is the resistance vastly different?

5. With the machine ON, and your DMM set to read to 5V DC, can you tell us what voltages you're reading on the Lamp Driver board on U1 pins 1, 2, 3, 21, 22, 23 and also the voltage on pin 23 of each of U2, U3 and U4 of the Lamp Driver board. These signals control which SCRs should illuminate specific lamps.

Regarding point 2.
See attached switch matrix below. I've filled in the cabinet switches in red. The blue circled switches are the ones you mention aren't responding in the switch test. Most of those not working are on the signal marked ST1 (Strobe 1). Can you confirm if the Spinner, Tilt and Slam switches are working? This signal is essentially derived from pin 3 (PA1 signal) of U10 PIA on the MPU board.

Regarding point 3 and 4.
Ok, so those lamps aren't on due to a short on the playfield.

Regarding point 5.
LDB U1 pin 3 being 1V is a problem. This is causing those spinner lamps to come on all the time. Infact the spinner 3000 lamp should also be on. Can you confirm if this lamp is blown?
However this doesn't really explain why other lamps aren't coming on so there's also another issue.
This Lamp Driver Board (LDB) U1 pin3 signal is essentially derived from pin 3 (PA1 signal) of U10 PIA on the MPU board.

Notice something in common here?

Now you've swapped the PIA in U10 with U11 and the symptoms didn't change. Note, this PA1 signal is also used for the displays and they're working, but it's wired a touch differently, so lets put that aside for the moment.
So something hanging off the PA1 signal coming from the U10 PIA is causing an issue.

1. Confirm if the spinner 3000 lamp is blown.

2. Confirm if the Spinner, Tilt and Slam switches are working or not.

4. Are any switches shown as always on in the switch test?

5. Measure the PA0, PA1, PA2 and PA3 signal voltages directly on the U10 PIA chip of the MPU board, that's pins 2, 3, 4, 5 respectively. We're interested in how the PA1 signal on pin 3 compares to the other PA* signals). It should generally be 2.0 - 2.5V in attract mode.

6. Do these same measurements again, however this time disconnect all three J1, J2 and J3 connectors off the MPU board. Wait till after the 7th LED flash on the MPU board so you know it's reached attract mode. This is to see what the PA1 signal is reading after having isolated the Lamps and Switches bus connected to it off the MPU board.

SpeakEasy-SwitchMatrix1.jpg

Oh btw, Lamp Driver board U1 pin 1 measures 0.4V during attract mode on my early Bally. It measures 5V during the power on self test and drops to 0.4V as soon as attract mode starts. You might want to confirm similar behavior and that it's not stuck low.

Cool, yeah right star rollover switch might just be dirty / gapped too much (it's a separate issue)..

Somethings dragging that PA1 signal down on the MPU board. It could be shorted to something from previous work done. Does it look like someones replaced the 40 pin IC sockets on the MPU board or any other work?

Look around the top right of the MPU schematic. There isn't too much connected to that PA1 signal. You can try disconnecting/replacing items if you have desoldering skills and equipment. If not, you could end up damaging tracks so you might be better off sending the MPU board to someone who can do it properly.

You still have the issue that no other switched lamps are coming on during attract mode right?

If it's not U20, some remaining items that connect PA1 to ground are R111 (56K ohm resistor) and C27 (390pf capacitor) via diode CR1.
So disconnect one leg of diode CR1, this will take out these 3 items from the PA1 circuit. It's sitting just above dip switch 32.
The non working switches still won't work but if there's something wrong there, the spinner lamps should no longer come on all the time and so you'll need to diagnose which of those 3 components is faulty.

If the spinner lamps still come on, the last remaining item on the PA1 signal to ground is C42 (470pf). It's about 1.5 inches to the right of connector J1. Disconnect one leg of this cap and see if the lamps still stay on.

Failing this, if you can provide clear detailed pictures (front and back) of the top half of the MPU board maybe we'll be able to spot something abnormal.

Thanks for the pics. Nothing immediately stands out. What are the small brown stain spots on the top right area? Might be worth cleaning the area later.

1. Are you still getting 1V on the PA1 signal or has it returned to around 2.2V?

Lifting the leg on diode CR1 has disconnected the coins and other switches on that column of the switch matrix so that's why they're still not working.
The CR1 diode is the most likely component of the three so time to check it. Do it with the machine OFF and disconnect J2 and J3 off the MPU board.
While the diode is still disconnected, set your DMM to diode test mode. Put the black lead of your meter on the side of the diode that has the band (which is the leg you've lifted towards the J2 connector) and put the red lead on the other side of the diode. It should measure about 0.6V . Swap the leads around and you should get no reading (i.e. the meter shouldn't respond). Do the same with diodes next to it to get a feel and comparison of how it should read. If it reads differently replace it. It's a 1N4148 diode and they only cost a few cents.

If the diode measures ok, then measure the R111 and C27 combo to ground. Set your DMM to high resistance mode and measure the resistance across R111. It's at the top of the board above dip switch 32. It doesn't matter which way around you put the leads and should read 56k ohms. Compare it to R108 which is right next to it to get a feel. If it measures differently let us know.
Lastly just measure the resistance across C42 and make sure it's the same as C41 and C43 next to it. It won't tell you if it's out of capacitance, but might tell you it's shorted (although it's pretty unlikely to be at fault), but worth doing anyway to get a feel of the load on the signal.

1. Can you list which lamps on the playfield aren't working?
2. Are the Spinner lamps still stuck on?
3. If you disconnect the Aux lamp board, does it make any difference to the playfield lamps?
4. What resistance is R32 measuring on the MPU board? It's next to SW33 up top and is a 3.3k ohm resistor. On my boards it reads about 2k ohm in circuit.
5. Can you post front and back pics of the MPU board, this time of the right hand side middle to lower area? The PA1 signal on the other end of the CR1 diode also goes there to the J3 connector for the cabinet switches (coins etc).

With the machine OFF, have you checked with your multimeter that these non functioning switches are actually making electrical contact? With your DMM in low resistance mode they should read zero ohms when closed.

Spend a few minutes and check every diode in the switch matrix throughout the playfield and cabinet including tilt/slam switches. While you're there, check the capacitors on switches that have them looking for any that are shorted.

With your multimeter, measure for any shorts to ground against the lugs of the coin switches.
Make sure you've got continuity all the way from the MPU board itself to the coin switches. Presuming you've got a "Rev L" Alltek board, next to J3 there are some small surface mount resistors.
The right side of resistor R116 goes to one of the lugs on all three coin switches.
The right side of R125 goes to coin switch 1 (left chute).
The right side of R128 goes to coin switch 2 (center chute).
The right side of R124 goes to coin switch 3 (right chute).
Check all these for continuity.
If you've got a Rev K or older Alltek MPU board, the resistors are different. If you know how to read schematics, they're available on the Alltek site.

If you want to try, you can simulate a coin switch on the playfield by briefly jumpering a wire from the left outlane special switch (the lug that doesn't have the diode connected) to the playfield Tilt switch on the diode lug with no wire, that should simulate coin switch 2.

Also regarding the lamps, did you try what Cheddar mentioned way above by shorting the SCR metal tabs on the LDB to ground to see if the corresponding lamp illuminates?

A few examples:
Q1 Right out special lamp
Q3 125k center cards lamp
Q9 Wheel flasher lower right lamp
Q10 5k right lane lamp
Q16 Ball in Play (backglass) lamp
Q22 10k right lane lamp
Q34 Wheel flasher lower left lamp
Q35 60k Bonus lamp
Q56 Right lane special lamp