I think there is another board called opto ramp board that have 3 optos on it. Check that board first.

Have you tried to bridge the receiver in test?

* I am no expert *

The thing I would do is disconnect J209 on the MPU and J2 on the opto board. Then I would check if I had continuity between the J209-1 and J2-4 (the white brown wire) plugs. We know that the column wire at J2-6 (Green-Gray) is good because the other optos on the ramp work.

If you do not have continuity from the J209 header to the J2 plug I would check every switch in that row for a wire break on the white-brown wire (Slam Tilt, Left Sling, Top Yellow, Top Green, Top Jet, Top Loop). I would say this is the most likely problem.

If continuity is good, you can try to fix the opto board or buy a new board. Since that board is loaded with 30 year old components and already hacked up badly at U4 personally I would just buy a new board.

Part A-15189 $99 on Marco

https://www.marcospecialties.com/pinball-parts/A-15189

But, if you want to try to fix the board:

plug J209 back in on the MPU, leave J2 on the opto board disconnected.

While you have the opto board out I would check the work that was done on U4. Page 118 in the manual has the schematic for the board. I would double check that each pin tones out to where it is supposed to go on the top and bottom of the board. If it doesn't, correct the work. Someone really butchered that chip swap.

Then I would jump J2-4 to J2-6 on the J2 plug and see if Opto 81 registers. You would be doing that without a diode in the opto 81 switch circuit so other switches might register as well. I would probably check continuity from J2-4 to the diode at D2 and from D2 to pin 2 on the LM339 at U1. Then I would look at replacing that LM339 at U1.

But before all of that, I would let somone else chime in and make sure I'm not giving bad advice.

He's looking at the correct board for Opto 1 (switch 81)

The ramp board only runs 2 optos (switch 84 and 85) Opto Made Loop and Enter Left Ramp.

I assume that switch 81 is the only switch giving you grief. If the other two switches 82 and 83 are causing grief then the following may help but it is possible that there is a problem elsewhere affecting all three optos rather than a single opto.

Try this:

• Get two alligator clip connectors.
• Disconnect J5 on the Ball Accelerator board.
• Enter switch edges test.
• Attach one alligator clip to one end of each of the colored lines in the pin list below.
• Attach another alligator clip to the other end of the colored line.
• Touch the alligator clips together.
• Note whether the switch registers in switch edges.
• Repeat for each of the brown, red and orange pin pairs.
• Report your results.

getaway_accelerator_board_opto_wiring.jpg

The reason I suggest using separate alligator clips is so you don't accidentally short pins on the header. Keep the pins as separate as possible using as much insulation to prevent accident shorts.

If you're concerned you should consider posting images of the optos that you installed. Images of the board and the wiring as you have connected it. Well illuminated and in focus images help tremendously.

For the record ... I do not have a Getaway and I have never seen inside one so I am working on theory not experience.

I just looked at the schematic and it shows that the corresponding LED (LED2) should change state when the opto is interrupted. Using the alligator clip test above you are actually causing the opto to be CLOSED. In other words the state should change in switch edges when you disconnect the alligator clips not when you connect them. Check the corresponding LEDs change state on the board with the alligator clip test when you disconnect the clips.

Another test you can do is take the transmitter (white plastic) and point it in front of another receiver (black plastic). The transmitters are all the same. Using different transmitters that are known to work can help sort out which receivers don't work.

I am not familiar with that receiver board you have installed. I do not know the manufacturer or merchant that you used. It looks like a replacement because Williams did not use A/C and K/E markings on their boards. Because these are likely replacements the phototransistor may be installed "backwards". You ruled out the actual circuitry of the Ball Accelerator board by using the alligator clip test. Try swapping the WHT-BRN and GRN-BRN wires in case the component is reversed. The phototransistor C and E leads are dependent on the manufacturer of the phototransistor. The datasheet specifies what it is but you don't know who the manufacturer of the phototransistor is when you buy a replacement board.

If you traced your row and column wires all the way through to that opto (which you said you did) and still have an issue.

Take a measurement of the 12v power supply at the opto board

I can only think of three possibilities
The opto transmitter receiver pair
MPU problem
Low 12v power supply to the opto boatd

Don't be so hard on yourself. You wired it correctly according to the manual and schematics. The WHT-BRN is the collector (higher potential). The GRN-BRN is the emitter (lower potential).

The issue is that whoever put the board together installed the phototransistor "backwards". They installed the collector lead of the phototransistor to the emitter on the board and visa versa. You should assume that the manufacturer installed the component correctly but unfortunately there are manufacturers who don't pay too much attention to detail. In essence they manufactured the product incorrectly. Ideally you should ask for help from the manufacturer or merchant who sold you the product rather than this forum.

With regular leaf or microswitches on the switch matrix there is pretty much only one way to wire them correctly. Otherwise they don't work properly. If you want to see an example of this you can take a look at recent posts in the scratch build Addams Family thread.

Both will NOT work correctly if wired incorrectly. They are BOTH polarized components. The transmitter has an anode (positive) and cathode (negative). The phototransistor has a collector (higher potential) and an emitter (lower potential). Because they are a form of "diode" the current only flows one way (from higher potential to lower potential). This is why you must wire them correctly. Or in this case install the component correctly so that whoever connects the wires is wiring it correctly.

You can get visual feedback of the transmitter working properly because it is an infrared LED (light emitting diode). If you have an infrared capable camera (most phone cameras are capable although the regular camera may have an infrared filter forcing you to use the "selfie" camera) you can often see the LED working. The phototransistor ... not so much. You need to measure voltage to see if it is functioning. The other way is to short the phototransistor (as you did above) and verify the state detection side of the circuit is working.