(Topic ID: 44584)

TAF opto strangeness


By kse001

7 years ago



Topic Stats

  • 22 posts
  • 8 Pinsiders participating
  • Latest reply 11 months ago by DRDAVE
  • Topic is favorited by 3 Pinsiders

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#1 7 years ago

I'm in the process of putting a TAF back together. I was getting opto errors on two optos: Bookcase 3 (#55) and Thing up (#85). All other switches, mechanical and opto, worked fine. I started by replacing the Thing opto, but it was still showing as being bad. Removed the LM339 ICs from the opto board under the playfield and replaced them with sockets and new ICs. Going into the switch levels test now, it continually cycles through all optos along with #24 (Always Closed). Strangely though, if I go into the switch edges menu, now all of the book case optos activate fine as do all the other optos except for Thing up - that one still tests bad. What would cause that strange behavior in the switch levels test though?

During testing I did unplug all the switch row/column switches from the CPU board and they started freaking out (same behavior as I described above in switch levels test), but I powered the game off and pulled the batteries so I'd have thought that would reset any issues that may have caused.

#2 7 years ago

Thing opto - new one good ? Soldered in right ? ( not all optos are created equal ).

LTG : )

#3 7 years ago

Not sure, but I believe so - it's a replacement board I bought from BAA. Both the original and the replacement test bad for Thing up, so it seems likely that it's something other than the opto (or it's a heck of a coincidence). I have the board hanging and was manually trying to activate the switches but no difference. Both switches are getting power to the transmitter (can see the glow when viewed through a digital camera).

Kyle

#4 7 years ago
Quoted from kse001:

Not sure, but I believe so - it's a replacement board I bought from BAA. Both the original and the replacement test bad for Thing up, so it seems likely that it's something other than the opto (or it's a heck of a coincidence). I have the board hanging and was manually trying to activate the switches but no difference. Both switches are getting power to the transmitter (can see the glow when viewed through a digital camera).

Kyle

Too cool. No one has never heard of having two bad receivers or a new one wired wrong.

Hey it's only two wires, you know before I start checking all the switch matrix wires on the same row and column, or the LM339 on the opto driver board, I'd try swapping wires just to see if it starts working.

If not you won't hurt anything, can easily swap them back, and then start digging through everything else.

LTG : )

#5 7 years ago

Hmm, something seems really odd. I swapped the two row wires on the IDC connector that plugs into the Thing opto board like you suggested. When I booted I still got the switch up error, but when I went into switch edges and tested, both optos seemed to be working fine (just opposite of where they should be obviously: up was 84, and down was 85).

So I switched the wires back to the way they are supposed to be and now the up one isn't working again. What would cause that behavior?

Kyle

#6 7 years ago

Connector mixed up ? Wires in wrong spots for both optos ?

You might have to do a facotory reset to clear error and see if it returns.

I'd get 84 and 85 working right first then see where you are at.

LTG : )

#7 7 years ago

Thanks. That's pretty much where I'm at too. But I'm not sure how to proceed with the switches. Why would both work when I swap the wires but when I put them in the right place the up opto doesn't work? I'm not sure where to look for that problem.

#8 7 years ago

How far apart did you dismantle the game? Time to trace all your steps. Did you mark all plugs to match the headers that they were removed from? Did you replace any diodes, or other components? Maybe post a few pics of how things are currently connected, and some TAF owners like me can help to identify proper locations of things.

Do a little research here too.

http://www.pinwiki.com/wiki/index.php?title=Williams_WPC#Miscellaneous_WPC_Boards

#9 7 years ago

Hey Kyle,

While I can think of some obscure reasons why you'd get that result when swapping the wires, at this point I'd start with simpler solutions like something else changed while swapping the wires around.

Are you testing the optos with a business card?

Is the thing assembly in the game? The reason I ask is the last little bit of movement that blocks the up opto is done by gravity. If the thing assy is not in the right position the opto won't close properly.

Quoted from kse001:

Going into the switch levels test now, it continually cycles through all optos along with #24 (Always Closed).

Not sure what this means.

#10 7 years ago

So right now I have been testing with a business card. The opto board is all wired up but not attached to the Thing assembly for ease of reaching it. When the IDC connector is wired correctly the opto for Thing down (sw 84) opens when the beam is broken by the card, but switch 85 (Thing up) does not. When I pulled the two row wires on the Thing opto board IDC connector and reversed them (I.e. put the wht/yel one where the wht/grn one was and vice versa) both opto switches worked. If the up opto switch.itself was bad I'd expect it to consistently fail, not work when the wire for rows 4 and 5 were swapped on the IDC connector. So that's where I'm currently stuck.

#11 7 years ago

Did you replace any of the opto's for thing? Did you replace any other electronic parts?

If you have these same wire colors/tracers, this is how mine is wired.

+12V (Grey w/yellow tracer)
GND (Black wire)
The next one with the arrow is unused
COL (Green W/Purple tracer)
ROM2 (White W/Green Hash Tracer)
ROM1 (White W/Yellow Hash Tracer)

#12 7 years ago

No replacements of the opto on Thing - I ordered a whole new 2 opto board from BAA to replace it completely since it wasn't that horribly expensive. But both boards (the original and the replacement) act the same way so I'm thinking the problem isn't the opto but something else.

I did swap out the LN339s on the 7 opto board under the playfield - installed sockets and added new chips. Prior to doing that both Thing optos were showing as being bad as was one of the book case optos. After I replaced those chips two of my 3 opto problems cleared up. But other than that, no electronics were replaced anywhere.

#13 7 years ago

Before we head down the complex path, just want to make sure you've replicated the result 2/3 times that when you switch the wires everything works.

I know it's a pain, but I've screwed myself before by not double or triple checking something like this. Especially when it gives such an odd result.

Next I would check the voltage at the optos and check all your voltages on the opto board.

If all that is good, I would say you've either got resistance in the wiring for switch 85 and/or a weak component in the 85 circuit. Check the resistance vs 84. It could be that two weak points are combining to make 85 not work and when you switch the wires you separate the two weak points and things work.

Based on what you've tried I would suspect the thing opto circuitry if it's a component. I don't remember what's on the board, but check resistors and anything else you can.

#14 7 years ago

Also, what does the switch levels continuously cycle mean?

#15 7 years ago

I had a very similar problem after doing a complete rebuild on my Addams Family.
After putting my playfield back in place I got and error on the thing up or down opto, can't remember which it was. When I put the machine into switch test and tested the optos they all worked fine.
Turns out when putting the molex back in place on the CPU board, one of them was one pin off and was causing the error.
May not be your problem, but any idea is a good idea for a broken pin.

#16 7 years ago

HighSpeed1: Yes, sorry I didn't see the wiring info you had posted before. Mine is the same as yours

Terryb: No, I have not tried it several times. Good point I will try it again today and verify that I get the same results. One thing I notices is that the end of the molex where the wires attach was kind of "crushed" like someone may have squeezed it with a pliers or something at some point. This would be where the row wire for the up opto connects. So I thought this was probably the issue, but reseating it with a proper IDC insertion tool didn't help and when I swapped the wires the other one worked fine like I said. Still, I suppose I could replace the whole molex just to be safe.

Regarding the switch levels, what I mean by that is that when I go into the switch levels on the test menu (T.2), the game starts cycling through the switches and alerts/displays them in the following order: 24, 53, 54, 55, 56, 57, 82, 84, 85. At first I thought this was a problem since I didn't recall this test working this way before, but after looking at the manual I see it is just cycling through all the switches that are closed. Makes sense for the optos, except that both 84 and 85 should not be registering as closed at the same time.

Arcade: Yep, I've checked that a bunch of times as I've already made that mistake in the past

#17 7 years ago
Quoted from kse001:

So right now I have been testing with a business card. The opto board is all wired up but not attached to the Thing assembly for ease of reaching it. When the IDC connector is wired correctly the opto for Thing down (sw 84) opens when the beam is broken by the card, but switch 85 (Thing up) does not. When I pulled the two row wires on the Thing opto board IDC connector and reversed them (I.e. put the wht/yel one where the wht/grn one was and vice versa) both opto switches worked. If the up opto switch.itself was bad I'd expect it to consistently fail, not work when the wire for rows 4 and 5 were swapped on the IDC connector. So that's where I'm currently stuck.

Does it look like either of the thing opto's have been replaced? I keep thinking that you say things worked when you reversed the wires, It reminds me of some opto's I bought from Marco to rebuild a Sys 11 stepper board. I replaced everything on the stepper board, and it still didn't work. I ended up buying a great lakes modular board, but a year later I decided to tackle the original board. Long story short, what I found was the Opto's I bought from Marco were backwards from the labeled DOT. I removed the Opto I put in and installed it backwards per the indicator dot, and my stepper board works fine now.

#18 7 years ago

Thanks a lot for all the responses. This project has really been a pain but I am so close now. I truly appreciate all the comments because as one person pointed out, when you're trying to troubleshoot these problems there really are no bad ideas.

Anyway, I think this has to be some kind of wiring issue. First I tried switching the wires around like I said I did earlier and this time it worked both ways. Then I removed the Thing assembly from under the playfield and just held it in my hand with the wires connected. When I did that and booted the game I had no switch errors and the Thing test registered both optos properly. But as soon as I installed it back under the playfield the up opto switch is stuck closed again.

At this point I'm not really too sure what to do other than try using a new IDC connector in case the "crushed" end of the original is somehow causing these intermittent issues. Unless anyone has any better ideas based on what I've been able to describe.

#19 7 years ago

One other possibility: the metal tab that blocks the opto is not rotating fully into position. Typically the last little bit of movement needed to block off the opto is provided by gravity rather than the motor.

While it's out of the game hold it in different positions and you can see how the thing arm (and therefore the metal tab) will rotate around as it's held at different angles.

2 years later
#20 4 years ago

Hello,
I'm having a similar issue with my TAF, but I'm quite positive that this is more than just bad connections.
Did you ever solve your problem?

If you're lucky, this video might help

Cheers,
Shachar

2 weeks later
#21 4 years ago

I had my thing up/down opto board rendered non-functional when somehow out of the blue that little tab that slides in and out of the optos caught a wire and tried to drag it through the opto space. It looks like the opto cracked at the PCB but haven't dug heavily in to it other than to see that the down opto fails the switch test now.

Anyway - I have heard that there is a new opto replacement board for this that buffers the optos from the switch matrix and supposedly draws significantly less power. Does anyone have any info on this? Was there a thought that the current design was problematic? It has worked fine for 20 years ....

3 years later
#22 11 months ago
Quoted from not4tilts:

I had my thing up/down opto board rendered non-functional when somehow out of the blue that little tab that slides in and out of the optos caught a wire and tried to drag it through the opto space. It looks like the opto cracked at the PCB but haven't dug heavily in to it other than to see that the down opto fails the switch test now.
Anyway - I have heard that there is a new opto replacement board for this that buffers the optos from the switch matrix and supposedly draws significantly less power. Does anyone have any info on this? Was there a thought that the current design was problematic? It has worked fine for 20 years ....

The new buffered Thing opto board should work well with Rottendog replacement MPU boards. Talking with an EE friend of mine about this and he concluded
Bally should have used the same LM339 opto board for the thing optos to report to but they didn't for some reason. So no buffering on thing optos just direct reporting to the switch matrix. And depending on sensitivity and thresholds of the different MPU boards, thing may not report correctly as the optos are not buffered. New board is how Bally should have designed it in the first place as it is a game weakness for this title.

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