(Topic ID: 150543)

BSD Mist Woes - Long Beam Opto - SOLVED

By The_Director

5 years ago


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  • 35 posts
  • 12 Pinsiders participating
  • Latest reply 1 year ago by unlockpinball
  • Topic is favorited by 17 Pinsiders

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IMG_5425_(resized).JPG
12755305_10102111636061451_85233300_o_(resized).jpg
24_inch_opto_board_with_extra_LED_(resized).jpg
diode_J3_1-3_(resized).jpg
A-15646_BSD_24_inch_long-beam_opto_test_22K_(resized).jpg

#1 5 years ago

OK, this one has gotten me, so I'm reaching out. Working on this for someone else. He sent me a video early on of a ground short to row 2 and the machine being really wonky. It wasn't doing the wonkiness when I got it and the U20 had already been socketed, so I dropped a 6803 in there.

Anyway, everything was working fine except Mist. So, I used Terry's guide and began troubleshooting Mist. The long beam opto read OPEN all the time. No amount of adjustment could get it to read closed without a ball there in single switch test. Long story short, all 3 LM339s on the 10 board opto have been replaced, both trans and receive opto replaced on long beam, have home pin board in the game and still that bastard won't read closed. Every other switch in that column and row work too, every other opto works. Am I missing something? Any help would be appreciated - thanks!

#2 5 years ago

Gotta start with the basics... You're sure the transmitter and receiver are working? Make sure the gates aren't in the way?

#3 5 years ago

I've lifted both gates to no avail. Home pin board green beam light is on, both optos have been replaced twice just to be 100% sure I hadn't erred and installed one backwards, etc.

#4 5 years ago

Is the opto getting power? can you see the beam with your cell camera?

#5 5 years ago

Yep, opto is getting power too. I'm beginning to feel it might be on CPU, but strange that every other switch in row and column is working fine.

#6 5 years ago

BSD has the 24 opto board for the mist ball optos. Your problem may lie in that board.

2 weeks later
#7 5 years ago

Replaced with the home pin board and still reading open all the time. I'm at my wit's end on this game -- any other ideas?

#8 5 years ago

I just went through what you are going through and got it after I replaced the optos, replaced the 24 board, and bent the metal.

Ok, did you take a remote control to the receiver and did it say closed at all when you pushed buttons? did you hold up you cell phone camera to the transmitter to see if you see the led light? I'll help you from there

#9 5 years ago
Quoted from nikpinball:

Ok, did you take a remote control to the receiver and did it say closed at all when you pushed buttons? did you hold up you cell phone camera to the transmitter to see if you see the led light? I'll help you from there

This ^^^.

#10 5 years ago

Today I had the opportunity to test with this 24" opto board.
With a 22K resistor ( that was the first resistor I had in reach ) it is possible to transfer the 40KHz output of the NE555 timer to the input of the MC3373 so that its output sets U2 optocoupler active and makes a signal for the switch matrix. Piece of cake !

So, put machine in switch test T1 with J1 and J2 disconnected from 24"opto-PCB and have a resistor by the hand to trigger this board as shown in the picture. If this works you can conclude that PCB + wires to switch matrix are all right and the problem has to be found at the opto on playfield.
A-15646_BSD_24_inch_long-beam_opto_test_22K_(resized).jpg

#11 5 years ago
Quoted from zaza:

So, put machine in switch test T1 with J1 and J2 disconnected from 24"opto-PCB and have a resistor by the hand to trigger this board as shown in the picture.

Fantastic idea zaza. I will definitely add this to my mist opto troubleshooting guide.

#12 5 years ago

Well done zaza. That'll help anyone working on a mist issue for sure.

#13 5 years ago

Also terryb your guide helped me fix all of my issues over the last week and i had 3 so thanks very much

#14 5 years ago

Thank you so much guys, this sounds very helpful and promising on helping narrow this down. Will test out tomorrow and update as needed. Thank you all again!

#15 5 years ago

If the green indicator LED on the Homepin 24" opto board is illuminated it is telling you that the beam across the playfield is operational and that both the TX and RX optos are working as they should be. It further tells you that the 40khz signal is being generated, transmitted, received and decoded correctly and that all the wiring and connectors to the TX and RX LEDs are intact.

Wave your hand through the (invisible) beam and you should see the green indicator LED flash on and off as you break the beam.

With this board fitted there is no need to be jumping resistors all over the place. That was the very reason we included the green LED- to make fault finding dead easy.

If all this works as described your problem is elsewhere,

#16 5 years ago

Most likely I will be able to test this trick with a resistor on a BSDracula today at the D.P.Museum.
If the machine is gone or I don't have time there, I will test it tonight with 'the Shadow' at home.

#17 5 years ago

Zaza if its any help, I can bring a Homepin board to that BSD today. It currently has the factory board.

#18 5 years ago
Quoted from Homepin:

jumping resistors all over the place.

Yes, that gives me the idea to jump a diode on J3 between pin 1 and 3 to give a direct signal to the switch matrix in switch test T1.
That also gives information in which direction to look.
diode_J3_1-3_(resized).jpg

#19 5 years ago
Quoted from jrcw:

I can bring a Homepin board to that BSD today

Hi jrcw, that will be handy
I have a WMS board with me to experiment with but let's see if we can test the homepin-board as well.

jumping in my car and heading for Rotterdam right now.

#20 5 years ago

It worked as expected in the BSDracula.
After all there was no need to use a resistor. This circuit is so sensitive, making a bridge with 2 fingers is enough.
And indeed very handy with an extra LED. With only power on the PCB connected it was easy testing to see if it was active or not.
24_inch_opto_board_with_extra_LED_(resized).jpg

#21 5 years ago

The OP sent me a PM a couple of days ago and I responded. I sent a detailed reply on faultfinding this board but I am unsure if he has seen it? I will reproduce it here in case it helps others with problems in this area. This same technique applies for testing of the original board as well as the Homepin replacement although it isn't as easy to fault find the original without the green "tell tale" LED:

************************************

I suppose the best way to start the fault finding is to separate the different functions of the board.

Let me say first though, reversing a diode (or LED) usually will not cause any harm. More damage will be done soldering and unsoldering it usually. Generally it just won't work if installed incorrectly. Diodes are designed to operate being reverse biased.

You can easily test the 24" opto board on the bench. Make up a couple of plugs - one with a TX and one with an RX LED soldered directly to the plugs, don't use long wires, just the leads on the diodes. (see picture) Plug them into the board and apply 12V to the correct pins on the connector (+12V to pin 5 and ground to pin 4). With the two IR LEDs facing each other, and only about an inch apart, the green beam light will almost certainly be ON. If it is NOT double check the orientation of your TX and RX LEDs and if still not on, get back to me!!!!!!!

Use a steel ruler, knife or similar to break the beam to confirm the green light goes on and off. Paper won't work here, it must be a metal sheet or similar.

This is the first step to prove that the board is OK and working as it should be.

A further step you could do to confirm that the board is working 100% is to wire a spare LED in series with a resistor (value of resistor is not critical, anywhere between 100R and 2K2). Fit this to the 5 pin plug between pins 3 & 4 (4 is ground) with the Cathode end of the LED facing pin 4 (ground)-(refer picture) and run a jumper wire between pins 1 & 5 of this same plug.

This LED will then turn on and off as you break the beam and PROVE that the OUTPUT from the board (that connects to the switch matrix) is operating as it should.

If you do all of the above you can rule out any issue with the board itself.

Next step is to plug the board into the machine and ensure it has 12V applied. Connect the TX and RX LEDs mounted in the machine. IGNORE anything else as you just want the green LED on the board to come on and off when you break the beam. Forget about the test mode in the machine. Just get the green LED on the 24" opto board working NOTHING ELSE!

If this doesn't happen you have faulty wires or plugs to the TX/RX LEDs or faulty RX/TX LEDs or incorrectly oriented TX/RX LEDs.

Once you have the green LED going on/off by placing your hand in the beam across the playfield, turn your attention to where the OUTPUT of the board goes in the games switch matrix.

Do the above procedures in the order suggested and once you have the green light working by breaking the beam DON'T go back and start changing TX/RX LEDs as you have confirmed they are working.

Move forward logically with fault finding - don't jump all over the place - get each section working, or confirm it is working and move on to the next.

Once working, this section of BSD is every bit as reliable as any other machine - it's just that the board is a bit of a mystery sometimes and it's easy to start jumping all over the place when trying to pin down an elusive fault.

Please let me know how you go.

EDIT: can't attach a picture to this message so please go here:

http://www.homepin.com/kits/bsd_jig.jpg

#22 5 years ago
Quoted from Homepin:

detailed reply

excellent tests !
With this write-up, I'm sure The_Director is already playing the machine.

#23 5 years ago

Bench tested the board using Homepin's suggestions and have verified that the board, transmitter and receiver are good to go! This really helps narrow it down -- thank you all, going to dig in in steed tomorrow and hopefully have this knocked out. Thanks again everyone, will update the final results soon.

12755305_10102111636061451_85233300_o_(resized).jpg

#24 5 years ago

So, I re-installed the board back into the game and know the board and optos are totally fine from bench test. However, I can't get the green beam test light on installed in the game. I've adjusted and removed about everything I can think of and not sure what is causing the beam to not register in game. I've attached pics of them in game right now. Terry's guide says, "It can be adjusted by loosening the three screws holding it in place and sliding the white case towards the front of the game." I'm not sure I understand where the three screws are that could be loosened and slid? There's only two holding it in place that I see. Thanks, again!

IMG_5425_(resized).JPG

IMG_5426_(resized).JPG

#25 5 years ago

I think he just means the two that are holding down the white casing? What if you shine a TV remote at the receiver? Does that light your green LED?

#26 5 years ago
Quoted from aobrien5:

I think he just means the two that are holding down the white casing?

Correct, I'll fix the typo.

Radio Shack sells an IR sensor card (at least they used to--if not MCM Electronics sells one). It would be well worth the money to pick one up and use it to align the beam. Even with the camera trick alignment can sometimes be a pain in the ass.

#27 5 years ago

Due to the way this circuit operates the adjustment (alignment) of the TX/RX LEDs is not that critical. Simply aligning them by sight will be good enough.

Determine that you have the correct LEDs in the correct positions and also that they are fitted the correct way around (orientation of the pins). Black plastic LED is the RX and the clear (or light pink) is the TX LED.

Also make sure the LED's are suitable for this application. Some people suggest certain types only will work but from our experience all LEDs that are 940nm wavelength specified worked when we tested them. We settled on a Taiwanese brand (Everlight) and have never had a single failure from over 2000 LEDs. We also use these same LEDs in our replacement trough opto boards and recommend them highly.

Spec sheets for the LEDs we use are here if it helps you determine the correct legs on the parts you are using:

TX http://www.homepin.com/parts/IR333C.pdf
RX http://www.homepin.com/parts/PT333.pdf

#28 5 years ago

Ok, so homepin board, receiver and transmitter are all working in game now. I guess the original transmitter I had wasn't 940nm or something. I think it was one I got from Marcos, but not entirely sure. It worked on bench, but not in game. I had a Radio Shack transmitter that was definitely 940nm that I installed and now we are functional in game but still OPEN in single switch test. At least we're narrowing down. Hopefully, this thread will be helpful to someone else once I'm through this. I'm sure it will be, wealth of knowledge here and thank you all again.

#29 5 years ago

The homepin board is awesome as it has been fixing most long range opto issues I have run into on both BSD and the Shadow.

#30 5 years ago
Quoted from The_Director:

Ok, so homepin board, receiver and transmitter are all working in game now. I guess the original transmitter I had wasn't 940nm or something. I think it was one I got from Marcos, but not entirely sure. It worked on bench, but not in game. I had a Radio Shack transmitter that was definitely 940nm that I installed and now we are functional in game but still OPEN in single switch test. At least we're narrowing down. Hopefully, this thread will be helpful to someone else once I'm through this. I'm sure it will be, wealth of knowledge here and thank you all again.

Man, I forgot all about the long beam opto being a different part from the regular ones. Glad you figured it out!

#31 5 years ago

BSD is good to go! Here's my blog update on the repair: http://carolinapinballrepair.com/2016/02/24/1992-williams-bram-stokers-dracula-repair/

Thanks again guys -- one of the main reasons I love this forum so much is the wealth of knowledge and willingness to help!

#32 5 years ago

Congratulations, but you should report your final fix here for posterity in case Pinside survives longer than your blog site does.

Also mark the topic as resolved.

#33 5 years ago
Quoted from The_Director:

I guess the original transmitter I had wasn't 940nm or something.

he did. But you're right, he should also mark it resolved.

#34 5 years ago
Quoted from aobrien5:

he did. But you're right, he should also mark it resolved.

The opto wasn't the ultimate issue. Per his blog, the red/white row2 wire had an open causing the switch to read open.

4 years later
#35 1 year ago

The HomePin board saved my Dracula!! A must to install in all Drac's. The green light opto test, adjustment screw, and updated board design is a must even if your current board works.

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