13.2VAC is fine.

What DC voltage do you read across the - and + pins of the BR2 bridge rectifier? Does it change if you disconnect J3 from the rectifier board?

Yep, you need J2 connected since your wall mains power goes through it to the transformer. J1 goes to the playfield - the output of BR2 doesn't go to the playfield so no need to disconnect it.

The point of disconnecting J3 off the rectifier board is to see if something downstream is loading down the BR2 bridge. Did you by any chance do any work on the solenoid driver board like change the large filter caps maybe?

Time to do a diode test on BR2 (machine OFF). The bridge is basically four diodes - if you look at the rectifier board schematic, you can see how the "diodes" are wired.

Yes, test BR2 using the solder points on the front of the board. Make sure J3 is disconnected so the meter results aren't affected by circuitry downstream.

Note FYI, BR1 and BR3 have ceramic resistors connected across them on the rectifier board so testing those two bridges in circuit in diode mode isn't so straight forward.

But BR2 can be tested in circuit no problems.

TP1 shouldn't have read zero volts with J3 disconnected off the rectifier board. Maybe your meter didn't make good contact during that measurement.
TP2 voltage commonly appears lower when J3 is disconnected. It needs the solenoid driver board connected via J3 to give proper meter readings.

The output of BR2 goes to the MPU board (J4) and the solenoid driver board (J3).

Reconnect the rectifier board J3 connector. Disconnect the J3 connector off the solenoid driver board and remeasure TP3 on the rectifier board. If voltage is ok, suspect the C23 capacitor and/or the 5 volt regulator on the large heatsink on the solenoid driver board .

BTW, what fuse have you got in F3 on the rectifier board? (should be a 4 amp fast blow). I'm a little surprised it's not blowing.

Both the AC voltage input to the bridge and the DC voltage output of the BR1 bridge measured ok but TP1 measured zero volts?

The 5.4V output of BR1 only goes to feature lamps - it's not connected to any other boards.

Can you post some clear pictures of the solenoid driver board and the rectifier board?
You can try unsoldering one of the wires connected to the large C23 capacitor on the solenoid driver board (to disconnect the capacitor). Reconnect J3 on the solenoid driver board and J3 on the rectifier board. Disconnect the MPU board J4 connector to isolate it away from power. Power up. If TP3 on the rectifier board now measures ok it might be the C23 capacitor at fault.

Just make sure you screw the rectifier board back in. BR1 needs to be mounted to the metal plate to keep it cool. Note there is an intermediate aluminum block that sits between the bridges and the mounting metal plate. You can see it's fallen down in your second picture. If you have some heat transfer paste, apply some.

Possibly.
With the machine OFF, disconnect J3 from the solenoid driver board (SDB). Use your multi-meter to measure the resistance between the metal case of the 5V regulator and TP5 on the SDB. You're effectively measuring if the 5V regulator input has some sort of short. If you have the C23 capacitor reconnected, the resistance will slowly rise over about a minute or so until the C23 cap charges. The final resistance reading when it steadies is the one to note.

Those resistance readings look about right to me.

Somethings not right here. As I mentioned earlier, a load drop like that on the 12V line should be blowing the F3 fuse on the rectifier board.

The battery in your multi-meter isn't flat is it?
Where are you connecting the black meter lead as a ground reference point? Does this ground reference point measure zero ohms continuity to the earth prong on the power cable plug?

Hook up J3 on the SDB again.
What voltage do you read between the ground leg of the big resistor on the rectifier board and the "GND" test point on the SDB?
What voltage do you read at test point TP5 on the SDB?
What voltage do you read at test point TP2 on the SDB?

[Edit] With the machine off, disconnect J4 from the MPU board and then power up. Measure the voltage at TP3 on the rectifier board The 12V supply also goes to the MPU board so let's see if it's related.

The TP3 voltages you're getting are kind of floaty and the value isn't saying much.

Ugh, sorry I meant TP1 (5V output of the regulator), not TP2.

Have you got any 12 volt incandescent globes? Say something around 5 watts?
If yes, hookup some wires to it. Disconnect J3 from the rectifier board. Connect your multi-meter to ground and TP3. Powerup.
Connect the globe across the two AC pins of BR2. Does the globe light? What is TP3 measuring?
Then connect it across the + and - pins of BR2. Does the globe light? What is TP3 measuring?

Just trying to see if the voltage supply into and out of the bridge is working under some known load.

If you're getting 16V DC with the SDB connected (and the C23 capacitor is reconnected), then this high reading can be normal! Capacitor C23 stores voltage and will bring the DC supply anywhere up to between 14.5 to 17 volts. You can confirm this by disconnecting J3 at the SDB where you will notice TP3 on the rectifier board will drop back to around 12 volts DC output.

Firstly, resolder that "-" pin on BR2. The solder on it looks a bit frosty in your picture above. If resoldering doesn't fix it then jumper ground to it. You are definitely onto something..

Are any feature lamps coming on?
What DC voltage are you measuring across the "+" and "-" pins of bridge BR1 on the rectifier board?

Solenoid power is also used on the sound board as a power source for the amplifier so the 43V supply is working.
What happens when you go to solenoid test mode and the game cycles through activating the solenoids?
As CanadianPinball mentioned, do you hear the flipper enable relay clicking on the SDB when you start a game and during solenoid test mode at solenoid test #11?

BTW before I forget, you have a couple of incorrect fuses on your rectifier board. The only slow blow fuse that should be on there is the one at F6 for mains power. Make sure your mains wall power cable is disconnected before touching that fuse and even the others for your safety..

Yes the lamps under the inserts are called feature lamps.

Sounds like BR1 might be blown. Did you power the game when the rectifier board was unscrewed from the mounting plate?
Those bridge rectifiers can be difficult to remove. Do a diode test across the BR1 bridge - you will need to unsolder one leg of resistor R2 (25 ohm ceramic resistor) and pull the unsoldered leg out of the board to disconnect it, remove fuse F1 and disconnect J1 and J3 from the rectifier board so you isolate BR1.

Press the little red self test button inside the coin door 3 times. The player displays will count from 1 to 11 and repeat with each number representing a coil/relay. The coil identification numbers are listed in the troubleshooting section of the manual.

First thing, measure the voltage at TP3 on the solenoid driver board. If it's zero volts (should be 5 volts) you have a connector issue on the short brown-white wire between SDB J3 pin 13 to SDB J3 pin 25. An open circuit here will cause no solenoids/coils to activate. Infact this is one of the recommended mods on the SDB to solder a wire on the back of the board from TP1 to TP3 to make sure the logic chips on the SDB have power.

SDB_TP3.jpg

If the pop bumper has a capacitor across the switch (it should) it might be shorted which is a common failure.

BR1 will die from overheating if not thermally cooled, but actually in your case with it not screwed to the metal backing plate it probably wasn't a cause of failure since the game hasn't been booting so none of the feature lamps were on anyway and there was no current draw through the feature lamp BR1 bridge.

It's a good idea to change all those capacitors on the switches under the playfield - the caps Bally used are prone to failure after all these years.
Replace with 0.047uF (47nF), 50V or higher caps. They can be sourced very cheap.

Yes, the trace path from transistor Q11 to J5 might have burnt out. Happens sometimes, the trace fuses before the playfield fuse (especially when someone has installed a higher amp fuse under the playfield
Check it with your multi-meter. You should read zero ohms continuity from the metal tab of Q11 to J5 pin 14.

I've had problems with the earlier Bally boards where they were not properly treated before they were soldered. Eg, when repairing MPU boards by replacing IC sockets and header pins my solder sucker leaves bare copper behind after sucking the solder. Recently I repaired a friends rectifier board in similar toasty condition to yours and the bridge legs had no solder contact with the copper traces - i.e. removing the solder revealed bare copper traces so the solder had never properly bonded to the copper from factory.

Anyway, great to hear she's up and running!