Very odd switched lamp issue with Centaur

[AlanJ]

Hi, I have a centaur, new to me. Got all the feature switched lamps going - replacing bulbs etc. All working fine for a few days. Now however all the "Orange" coloured insert feature lights will not light. They are the "Orb" feature lights, namely the 4 orange arrows in front of the 4 orb drop targets, the 1,2,3,4 orb lights towards the bottom of the playfield and the two orb release lights - one at the bottom the the top right hand lane, and one at the top of the captive ball lane.

Looking at the schematic these are all controlled individually off the lamp driver board. Unlikely that the lamp driver has blown all 10 of these circuits at once, so I'm trying to figure out what else it could be.

Non of these lamps light in the lamp test mode, nor do they light when you press the right flipper button when in game over mode - doing this makes it goes through the sequence of showing each set of feature lights, all the others work, apart from this "orb" set.

I'm totally flummoxed now.

Help please!

 

[Moonraker]

Replace all bulbs then report back..!

 

[andy]

The decoder chips on the lamp driver board control groups of lamp driver scrs, on the schematic do all these lamps trace back to a common decoder?

 

[Moonraker]

Or swap known working bulb with one not working to confirm if blown or not.

 

[AlanJ]

The decoder chips on the lamp driver board control groups of lamp driver scrs, on the schematic do all these lamps trace back to a common decoder?

no they are spread out across the board


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[AlanJ]

Replace all bulbs then report back..!

All bulbs were working earlier. even when i start a game none of these orange lights light up. surely it can’t be one blown bulb taking out the whole lot? I’ll try it. i’ve also got a spare lamp driver board so may just swap it out to rule it out as it’s a quicker swap than swapping bulbs


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[AlanJ]

Or swap known working bulb with one not working to confirm if blown or not.

Ok i did that with a couple of the non working bulbs and they are still not working


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[pinballmania]

Is the supply voltage present at all the lamps as it should be. A break would kill all lamps downstream

 

[AlanJ]

Aha! Well It help if you swap the right bulbs, I swapped non working bulbs around ! The problem is that every single bub in the "orb" set has blown?????? All 10 of them. I had them all working last week, when I got the machine some were working, the non working I replaced 5 or 6 of these with brand new, and all was well for several days, all bulbs working correctly. It looks like there must have been a massive spike of power that has somehow taken out just these lights? Very Very strange indeed. I can only imagine the spike happened when only these bulbs were lit????

Lessons - never assume - even if you have just replaceed bulbs, go back and retest them WITH KNOWN good bulbs! Thanks @Moonraker !

 

[Moonraker]

At least you only had 10 to replace, I've had to replace 40 before now...!

 

[AlanJ]

any idea what causes a mass blow like this?


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[new forest pinball]

Naff, cheap, Chinese copy lamps.... in my opinion, or some 1 in million power surge. But no idea really...I replaced all lamps in a HGOT once. Turned it on the next day and only six still
Worked. Two in the g.i. and four inserts... took me a good few hours of panic dmm testing to realise they had all blown. Never thought to check them first as they were new and presumably ok. Lesson learned.... K.

 

[Moonraker]

Inadvertent short, spike or surge. Takes out the entire string of lights. Also known flashers not to work if enough bulbs in the string are blown which really messes with your head as you can test working bulbs in the string..!