(Topic ID: 123570)

DW Dalek Wobble head triggers slam

By Clnilsen

4 years ago

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  • 26 posts
  • 6 Pinsiders participating
  • Latest reply 4 years ago by gcp
  • Topic is favorited by 3 Pinsiders


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#1 4 years ago

Just got around to finally installing my Dalek wobble head kit, which by and large looks pretty good.

Enabled in the software, and ran the now viable T15 test with no errors.

However, when I play a game and trigger the time expander mini playfield, as soon as it starts to move and get the "Ex" of exterminate out the machine triggers a "SLAM" and resets???

Everything looks as indicated on the wiring harness, not sure what else to track down on this. Anyone else have this problem after a new install?


#2 4 years ago

Bumping this, hoping someone has an idea. Game plays fine with the dalek head uninstalled.

Anyone else ever run into this?

#4 4 years ago

Well, I think I've narrowed it down. The yellow wire from the dalek head kit ( I don't have a wireing diagram, so not sure what it does) into the pin 1 on J208 block on the cpu board seems to trigger the slam when the head kicks on. Removing the splice and returning the plug back directly into the cpu board fixes the slam problem. Oddly enough though, without any wobble head errors.

color me confused....

#7 4 years ago
Quoted from pinball_faz:

Actually, why not give Mark an email (might have to go through Al Warner). I'm sure he knows the electronics of this quite well.

Naww that would have been too easy... lol. Will do!

Quoted from jadziedzic:

Check the diode on the head limit switch - it's probably installed backward. Or perhaps you've reversed the wiring for J208 and J206 (i.e., maybe that yellow wire is intended for J206 instead of J208). Which switch & diode terminal does the yellow wire connect to inside the head kit.

The splices pre-wired in the kit preclude this, thought I had a very similar thought.

#8 4 years ago

Just an update on this... no reply from Mark unfortunately. My plan is to pull this out this weekend and see what I can find.

Quoted from jadziedzic:

Check the diode on the head limit switch - it's probably installed backward. Or perhaps you've reversed the wiring for J208 and J206 (i.e., maybe that yellow wire is intended for J206 instead of J208). Which switch & diode terminal does the yellow wire connect to inside the head kit.

Dumb question, but how would I know if the Diode installed backwards?

If anyone has a wiring diagram for this to use to verify everything is done properly, that would be a huge help!


3 weeks later
#10 4 years ago

So, pulled my wobble head apart, and I'm not certain this aligns with how this is supposed to be wired. Mine is as follows:

J206 Pin 9 -> Green Wire -> "Col" Pin on wobble head board -> White Banded side of Diode -> Head Switch -> "Row" Pin on Wobble Head Board -> Yellow Wire -> J208 Pin 1

I guess fundamentally, are those the correct pin pinouts at least? If so, does it sound like the green wire in my kit is the green wire referred to above, and my yellow wire is the "white"?

Col pin connects to J206 Pin 9 / Row pin connects to J208 Pin 1

Col pin connects to banded side of Diode

#11 4 years ago
Quoted from terryb:

The whit-xxx wire goes to the unbanded side of the diode. The grn-xxx wire goes through the switch and then to the banded side of the diode. There's a picture of this setup at the top of the switch matrix diagram in the manual. Below the matrix is a drawing of a generic switch circuit.

So, just to check this - I unsoldered it and reversed the direction of the diode on the board. It *did* solve the slam-tilt problem so at least the game is playable now, but now the head wiggle test fails (which it didn't before).

As a dumb question regarding diodes; how fragile is a diode? I had to fight with it to get it released from the board, and I hope that I didn't screw up the diode in trying to flip it around.

#13 4 years ago
Quoted from terryb:

I presume you don't have a schematic for the wobble head kit?
I would contact whoever makes the kit.

Pretty sturdy, unless it's 20 years old and then who knows. Test the diode with a meter and you'll know for sure: meter in diode/continuity and will read OL in one direction and .5-.7 in the other direction.

No, I don't have the schematic unfortunately. It is Al's kit, but there's no schematic available and no response from them. Maybe someone who has this kit could verify it running with no errors.

#16 4 years ago

Well, here's the current status - Me: At my wits end

I tried reversing the wires, and still get an error on the wobble head test. Putting things back to originally how it was wired enables the backbox head test to go smooth.

Digging into the switch test, I tested switch 81 which is the backbox head switch and I can block and unblock the sensor fine, with perfect results.

Shifting to the switch 21 on the switch test also seems to work fine. Normally open, and if i block the backbox head switch while on the slam tilt / 21 switch test, it DOES NOT trigger the slam tilt switch.

So, to summarize:

- Anything other than the wire/diode trace as it came triggers backbox head errors
- Reversing the diode direction and / or reversing the wires on the inputs on the backbox head circuit board eliminates the backbox head / slam tilt problem in game, but causes the backbox head not to function in game.
- In switch test mode, there appears to be no behavioral connection between the slam tilt switch and the backbox head switch. The issue ONLY arises in the actual game.
- Unplugging the backbox head, but leaving it enabled in the firmware does NOT cause a slam tilt when normally the backbox head would be enabled in the game (i.e. mini playfield up / multiball situation)
- The common pin between the backbox head switch and the Slam-tilt switch is 208-1
- Unplugging the slam-tilt leaf switch at the front of the game has no effect on the problem.

This is how the board was wired as shipped / is current wired:

JP 208-1 -> Switch on head circuit board -> Diode (unbanded side) ->Diode (Banded side) -> JP 206-9

One final thought... Looking at the manual, it appears the way this SHOULD be wired is:

JP 208-1 -> Diode (unbanded side) ->Diode (Banded side) -> Switch on head circuit board -> JP 206-9
I note that this causes the backbox head error, but not the slam-tilt issue.

As much as I'd really like to get this working (especially since I expect this to be a plug-and play kit) I'm wondering if I should remove the backbox head switch from the circuit and leave everything else enabled, to see if I can get the head to at least move. I'm not certain what function the head switch does - besides let the machine know the position of the head. I assume it will still run, just not recenter?


#17 4 years ago
Quoted from ArcadeTechNerd:

Well... unless something changed in the design of the later runs I have had the kit in my Doctor Who for a few years now and have never seen any issues caused by it.

Do you get any errors in the backbox head test (T15 test) in the firmware? This would be great to confirm.

If possible, could you do me a Huge favor and confirm as much of the wiring as you can - i.e. at least confirm which pins are used on the JP 206 / 208?

Any insight into a working version of this would be GREAT to know.


#20 4 years ago
Quoted from gcp:

I've got a Doctor Who in front of me with the motorized Dalek from Basement Arcade - is this the same kit you are struggling with? Happy to take any photos/do any testing you might need.
Let me know if I can be of any help.

That's exactly the one! Three things I need if possible:

1) does the t15 test on yours complete with no errors? (I realize this sounds a bit crazy, but it would be helpful to know the kit actually does not normally throw off errors in the test. Especially as the instructions make mention of not knowing how to clear old errors!)

2) a picture / confirmation of the 2 pins that the kit connects to on the cpu board ( I think j208-1 and j206-9, but need to confirm which pin in the each block they are connected to.) I believe this is a green wire and a yellow wire.

2) if its accessible, a picture looking down on the circuit board so I can see the orientation of the diode in relation to the two wires from the blocks above in #2.

Any one of these would be hugely helpful to me!!! Thank you so much in advance!

#24 4 years ago


Ok, finally got this - it was a combination of two things.

1) The Diode on switch 82 (playfield glass) was backwards. Why didn't this every cause a problem before you ask? Well, it's because there was never a forth "corner" in the switch matrix rectangle (i.e. #81) until I installed the backbox head to cause a short problem.

The rectangle being Switches 21-22-81-82

This is from the Dr. Who manual, which I found immensely helpful:

"A shorted diode in the switch matrix can cause other switches to appear closed. these "phantom" switches (though not actually closed) complete a rectangle in the switch matrix. Therefore, if two switches in the same column are closed (example # 22 and #24) and a third switch is pressed in another column but in the same row as one of the first two (example #32), the "phantom" switch #34 is falsely indicated as closed. The switch with the shorted diode is diagonally opposite the "Phantom" switch (in this case #22)

I noticed something changed when I had the coin door open for once and the error did NOT occur. That gave me three of the corners, pointing me to the playfield glass switch to check out.

2) Secondly, the diode in the backbox head circuit was backwards as well!

a HUGE thank you to everyone who helped me on this! Game on!

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