CobraPin Coil wiring requirements

[Ryan HoltKamp]

I've wired up all coils.  In service mode, every coil works fine with coil_pulse.

Just got my game shooting.  The ball is bouncing around three pop bumpers, I'm flipping the flippers, and may have been pushing on the slingshots too.  When I do so, it blows fuses.

My question is whether there's a limit to how many coils per bank can be fired at once?  I've got slings and 3 pop bumpers on one bank.  Flippers are on another bank.

My coil default_pulse_ms is set to 20.

I'm using the most current beta version of mpf.  0.56 iirc.

Using a matrix for all switches except the flippers

It's certainly plausible I've wired grounds incorrectly.  I'll investigate that further.  I'm also using a dead Baywatch pin for my playfield, and that could have wiring/component issues I'm unaware of. 

[cobra18t]

I have no good answer for how many coils can fire at once on a bank. It depends on the coils you have connected to them and the rating of the fuse you are using. I also have pops and slings on the same bank but do not have an issue.

So is it the fuse for the pops and slings that blows or the fuse for the flippers? What size fuse are you using? Are you confident that 20ms is the correct default pulse? A pulse that is too long for your hardware can cause an overcurrent. 

Share the log when an event like this occurs and we can at least see which switches are being activated. Sharing your config could help as well.

[cobra18t]

Also, is it possible your pops or slings are machine gunning? You should limit how often they can fire with something like recycle factor:

https://docs.missionpinball.org/en/dev/hardware/opp/drivers.html?highlight=recycle%20factor#recycle-factor

[Ryan HoltKamp]

First fuse blew for the poppers/slings.   Replaced that, and the second playtest blew the flippers (maybe both).  I may have a mutual ground there somewhere; gotta do more digging.

How do I learn what's the proper fuse?  Also, how do I know what the correct default pulse would be?  Especially with several coils on the same bank/circuit?

I'll definitely share the log in the future!  For now, it's likely no use.

The right flipper is definitely machine gunning.  One thing to note is that there is an upper and lower flipper on this machine.  I've wired them together in parallel so they fire at the same time.  I'll rewire them separately.  I just noticed the right flipper tag was set to "tags: right_flipper0"  Maybe that appended 0 was part of the issue?

My coils are single wound with no hold circuit.  Config below:

coils:
  c_flipper_left:
    allow_enable: true
    number: 0-0-9
    default_hold_power: 0.125
    default_pulse_ms: 10
   
  c_flipper_right:
    allow_enable: true
    number: 0-0-10
    default_hold_power: 0.125
    default_pulse_ms: 10

flippers:
  left_flipper:
    main_coil: c_flipper_left
    activation_switch: s_flipper_left  

  right_flipper:
    main_coil: c_flipper_right
    activation_switch: s_flipper_right

switches:
  s_flipper_left:
    number: 0-0-11 #0-0-17
    tags: left_flipper
  s_flipper_right   :
    number: 0-0-9 #0-0-25
    tags: right_flipper0

Thanks for all your help!

[cobra18t]

The original game manual is a good place to start on sizing fuses. How did it group the coils? What size fuses did it use?

Start with the default pulse at 10ms and adjust from there.

Each flipper should be on its own transistor as you mentioned. You could activate both upper and lower flippers from the same switch if you don't have staged flipper buttons. That is what I did.

You never mentioned the size of fuses that you blew. What were they?

Can you share your pop/sling config as well?