Doctor Who: yet another opto bank problem

0

#1 2 years ago

OP

CTD

CTDnEUG

Pinside member

3y 25,400 22

I have an issue with my Dr Who 5-opto target bank (that is not quite addressed by the many other opto-bank posts on Pinside).

I had a problem with switch 74 not working since I got the machine. After disassembly and a quick visual inspection, the opto receiver for that switch seemed to be damaged. I soldered in a replacement receiver, but it still does not register hits to the mushroom button. And ... now switch 73 stopped working as well.

However, when I test with the opto bank plugged into its connector (but not reinstalled in the MPF), I noticed if I jam a fingertip into the space between emitter & receiver, I can get both switches 73 & 74 to register (on the Switch Edges test)! So it appears that both emitter and receivers are working, but somehow even with the mushroom button stems blocking the IR beam, still enough light is reaching the receiver that it does not trigger.

Is that possible? Any suggested fixes?

I have checked the emitters with a digital camera--all seem to be shining brightly.
I have installed Swink's aftermarket channel stiffener (https://www.shapeways.com/product/W3GJK4YJQ/doctor-who-mushroom-target-channel-add-on) which has light baffles built-in, so light leak from an adjacent opto seems unlikely (and these are 2 of the middle targets, so light is not leaking in from the end of the channel. And my original construction paper light shield is intact.
I have a multimeter, but am not sure exactly how to test the receivers for proper resistance, etc. with the bank unplugged from machine.

Any suggestions for next steps? pinball_faz have you seen this before? Thanks!

0

#2 2 years ago

KJO

eyeamred2u

Pinside member

Cleveland, OH

6y 63,300 2,367 6

OP
Quoted from CTDnEUG:
I have an issue with my Dr Who 5-opto target bank (that is not quite addressed by the many other opto-bank posts on Pinside).
I had a problem with switch 74 not working since I got the machine. After disassembly and a quick visual inspection, the opto receiver for that switch seemed to be damaged. I soldered in a replacement receiver, but it still does not register hits to the mushroom button. And ... now switch 73 stopped working as well.
However, when I test with the opto bank plugged into its connector (but not reinstalled in the MPF), I noticed if I jam a fingertip into the space between emitter & receiver, I can get both switches 73 & 74 to register (on the Switch Edges test)! So it appears that both emitter and receivers are working, but somehow even with the mushroom button stems blocking the IR beam, still enough light is reaching the receiver that it does not trigger.
Is that possible? Any suggested fixes?
I have checked the emitters with a digital camera--all seem to be shining brightly.
I have installed Swink's aftermarket channel stiffener (https://www.shapeways.com/product/W3GJK4YJQ/doctor-who-mushroom-target-channel-add-on) which has light baffles built-in, so light leak from an adjacent opto seems unlikely (and these are 2 of the middle targets, so light is not leaking in from the end of the channel. And my original construction paper light shield is intact.
I have a multimeter, but am not sure exactly how to test the receivers for proper resistance, etc. with the bank unplugged from machine.
Any suggestions for next steps? pinball_faz have you seen this before? Thanks!

What color is the Swinks channel stiffener? Needs to be solid black.
Many times, Opto's need to be replaced in pairs, both emitter and reciever.

I believe there are posts that explain how to test emitter and recievers with a multimeter and you can use a flashlight on the reciever and your multimeter to see voltage change when you shine the light on it, then remove it. I have notes, I will post more when I find them

0

#3 2 years ago

FAZ

pinball_faz

Pinside member

Chicago Burbs, IL

12y 94,300 2,733 5 32

Run a full switch test... all of them with a ball. Make sure you don't have a matrix issue.
Buzz the wires from the connectors to he opto board component LEGS not the pads.
Inspect the solder joints on the board
Camera check is a good one.. half the system works.
Check the 12 way connector to make sure the pins look good.
Plug the connector back in and buzz to the board from the other side of the game-side connector.

Put game in switch test, press in the buttons, give the connector assembly a good wiggle... see if there's intermittent contact... broken wire / bad connector.

faz

0

#4 2 years ago

OP

CTD

CTDnEUG

Pinside member

3y 25,400 22

Yes I noticed Swinks only offers black ones now--unfortunately I had it made in blue for some reason. I'm going to blacken the inside of it first, and see if that makes a difference. Will start further troubleshooting from there, if needed.

0

1

#5 2 years ago

???

catvilledoorman

Pinside+ Addict

Spokane, WA

5y 34,650 48 21

Look at your leds with a cellphone camera, your finger test might have been blocking ambient light. Look very close at your solder connections, cracks are really common, this area gets slammed. I had your prob exactly. combo dead leds and cold cracked solder. Wires as well as led leads.

0

#6 2 years ago

???

catvilledoorman

Pinside+ Addict

Spokane, WA

5y 34,650 48 21

sorry, reread and see you used a camera...good on ya.

0

#7 2 years ago

JDS

swinks

Pinside+ Addict

11y 124K 9,456

my apologies that the blue carrier option that has been an issue for 2 people and hence why it is black only - only sold 3 in blue with one having no issues.

Tape off and give a light paint of the black to the inside.

0

#8 2 years ago

KJO

eyeamred2u

Pinside member

Cleveland, OH

6y 63,300 2,367 6

OP
Quoted from CTDnEUG:
Yes I noticed Swinks only offers black ones now--unfortunately I had it made in blue for some reason. I'm going to blacken the inside of it first, and see if that makes a difference. Will start further troubleshooting from there, if needed.

when I painted the inside of mine then plugged in my opto board, it made the sweetest sound of all the optos working again. I hope this solves your issue. If not, we are here to help.

0

#9 2 years ago

OP

CTD

CTDnEUG

Pinside member

3y 25,400 22

eyeamred2u that's encouraging! I haven't had time to implement the fix yet. (And I'm a little nervous to try to buy black spray paint at the moment!) Will let you know.

0

#10 2 years ago

KJO

eyeamred2u

Pinside member

Cleveland, OH

6y 63,300 2,367 6

OP
Quoted from CTDnEUG:
eyeamred2u that's encouraging! I haven't had time to implement the fix yet. (And I'm a little nervous to try to buy black spray paint at the moment!) Will let you know.

I used Testors Acrylic Black Flat model paint and a small hobby brush rather than spray paint to do the inside.

0

#11 2 years ago

FAZ

pinball_faz

Pinside member

Chicago Burbs, IL

12y 94,300 2,733 5 32

I've not had much issue with light reflection inside the opto carrier. Most light noise I've seen is from outside the carrier. The white light from the lock lights is enough and if you but some crazy bright LEDs in the game that could do it too. Is the carrier wrapped in some sort of light blocking material?

https://pinside.com/pinball/forum/topic/tech-doctor-who-please-help-survey

faz

0

1

#12 2 years ago

OP

CTD

CTDnEUG

Pinside member

3y 25,400 22

Well, I obtained some no-name flat black spray paint at the drugstore. Sprayed the inside of the swinks carrier. Reassembled and now all 5 switches work perfectly. Apparently it was just the reflections from the blue carrier. Grateful for such an easy fix! Thanks everyone.

By CTDnEUG

2 years ago

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