Roller Derby ABCD lamps blow when the feature is awarded

By robertmedl

5 months ago


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  • Latest reply 5 months ago by baldtwit
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#1 5 months ago

On a Roller Derby, there are three lamps behind the backglass letters ABCD. When the feature is awarded, the lamps blow. With the game on and not running, I can replace the lamps and manually activate the Magic Screen Feature Unit and the lamps light and do not blow. But when the game is running and the feature is awarded, the lamps blow.


#2 5 months ago

Got the right bulbs in there ?

LTG : )

#3 5 months ago

Robert, if you trip a super section does that light blow as well? Maybe you have a short on the magic screen feature disc.

#4 5 months ago

Using an analog multimeter could you see if the voltage spikes when they are activated and then goes back to normal? Might be noticable with a digital one too but analog multimeters are easier to track with stuff like this.

#5 5 months ago

are the wiper fingers on the end mixer in their proper slots?

#6 5 months ago

Not sure on this game but I know my woodrails (Lovely Lucy, World Champ and Mademoiselle) all had sandcaster resistor in there that came off the 24 volts and went to the special light, bringing it down to 6 volts (or close to that). If it has one of those in line, I would consider testing the voltage and replacing it.

#7 5 months ago

One balls have a circuit like that, but bingos do not - 6V is tapped directly off the transformer.

It's likely a 50V short to lamps. Is one of the lamp fuses blowing?

#8 5 months ago

Thanks for all the ideas.

-- The lamps blow if they are 47s or 55s.
-- The Super Section lamps do not blow when tripped.
-- The lamp fuse does not blow.
-- The wiper fingers are correctly aligned on their rivets, and it is installed in the correct position.

Here is the reply I got from Jeff Lawton, similar to Otaku's response, which I think is correct. Am going to try this now and will report back.

"I suspect the 50 volt pulses to the step up coil are finding their way to the sockets of those three lamps. Probably a short on the unit. Lift the feed wire to the three sockets and put a test relay on the wire. Electrically cause the ABCD to advance. If the test relay pulses when the unit gets to the lighting position you will know there is a short on the unit. "

#9 5 months ago

Well, wiggle the damn wires, Robert!

That turned out to be the solution. Some of the wires coming into the unit are frayed and were making contact where they should not have been, presumably causing the short that caused the lamps to blow. It's working for now -- I played a few games, turned machine off and on couple times, scored some winners, etc.


#10 5 months ago

If you have strands of wire that have broken free, you need to resolder the wire - it will shake apart again and blow your lamps in a weird way again in the future. So does this mean that your RD is all done?

#11 5 months ago
Quoted from bingopodcast:

If you have strands of wire that have broken free, you need to resolder the wire - it will shake apart again and blow your lamps in a weird way again in the future.

Yeah yeah yeah.... I know how to do it right. I just don't want to (I will, though.)

Quoted from bingopodcast:

So does this mean that your RD is all done?

98% done.

1) Mixer 2 relay buzzes a little too much some of the time. An annoyance.
2) Maybe half the time, the game will tick off an additional credit, cycle, and potentially award odds and features when you shoot the first ball. Jeff suggested that this is due to a break-before-make SPDT switch that isn't breaking-before making. I think he said it was on the Control Unit, perhaps switch 3. But don't quote me on that....

#12 5 months ago

1) Lose more hearing. Works for me! Typical relay maintenance here - adjust your switches so that the spring isn't pulling so hard against the plate when engaged.

2) Sounds reasonable to me. Lots of logic in switch stack 3. Also check your start relay for arcing/gap on the hold switch? But Jeff is invariably correct.

#13 5 months ago

jeff probably said shutter cam 5D switch was acting MBB. Short together wires 61 and 93-2 while the shutter motor is running and you'll power the timer cams index and mixer latch coils.

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