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Is this ghosting? Or a wiring fault?

Durzel I think you're making progress mate:thumbs:

Have you tested the start button light diode - using diode setting on DMM as described here http://www.pinrepair.com/begin/#howdmm

Is it possible the elusive screw could have fallen into the start button/coin door boards or wiring?

Perhaps this problem existed before you started installing LEDs?
 
:) Thanks. Depressing and frustrating that I can't figure it out though.

Haven't tried testing start button diode yet. The start button barely illuminated before I changed it to a LED. It didn't come on at all in Single Lamp test mode (I suspect because the pulsing was too fast for it?) but did come on - dimly pulsing - during attract mode.

It's possible this problem always existed but was never actually visible because of the higher voltage/current use of incandescents and slower response.

Screw definitely wouldn't have made it as far forward as the front of the machine, the playfield was fully up when it fell out.
 
Durzel said:
:) Thanks. Depressing and frustrating that I can't figure it out though.

Haven't tried testing start button diode yet. The start button barely illuminated before I changed it to a LED. It didn't come on at all in Single Lamp test mode (I suspect because the pulsing was too fast for it?) but did come on - dimly pulsing - during attract mode.

It's possible this problem always existed but was never actually visible because of the higher voltage/current use of incandescents and slower response.

Screw definitely wouldn't have made it as far forward as the front of the machine, the playfield was fully up when it fell out.
Click to expand...

I'd wager the fault was already there.

Forget the screw ...I have dropped and lost numerous screws over the years into the cabinet black hole. I actually can't remember one then going on to cause a problem. It's always a possibility ... but it's actually pretty small chance.
 
Yup, seems that way. I was very meticulous when I was doing the LEDs, so it was quite frustrating when this problem appeared.

I just wish I knew enough about this stuff to be able to localise the fault. Feel bad having to come on here to ask mundane questions. :(
 
Durzel said:
Yup, seems that way. I was very meticulous when I was doing the LEDs, so it was quite frustrating when this problem appeared.

I just wish I knew enough about this stuff to be able to localise the fault. Feel bad having to come on here to ask mundane questions. :(
Click to expand...
if it was a mundane question you would've had a solution by now! Proves it's not an obvious fix. Don't fret, it's what we're all here for.
 
Are J138 & J133 sound? Any possible shorting on the front or back of the board?

I remember a few years ago my father was without water from his solar-powered well in rural Spain for days once... just so happens i was visiting around that time so i took the PCB out of the Solar controller and found a little bit of solder was shorting 2 contacts - stopped it all working. He was ready to hit stuff with his hammer, using a drill to aim:
homertripod.jpg

I've seen some nasty blobby solder work on the back of those connector pins.
 
Not sure, and not in front of machine at the moment.. Will have a look later and report back - thanks :)
 
Yup the symptom is weird, the fact it only applies one way around (Col 7 to Col 8) makes me think a polarised component like a diode is involved somehow (but I'm no expert).

Come on people, group hug...:clap:
 
It's column 8 lighting 7, not 7 lighting 8, but yeah... it's very weird.

I also don't really understand why removing the start button bulb would actually change anything either. The circuit is still live without it?

Knowing my luck lately the missing wood screw fell down and pierced the yellow-grey wire, then melted to form a microscopic conductive channel to an insert somewhere. Life finds a way!
 
The diode for a lamp and the lamp/l.e.d are in series, so without something in the socket it's an open circuit.

If both these lamp wires are in the same connector, that's not right. Columns and Rows have separate connectors.

For some reason, I can't get the manual for FunHouse from ipdb, but the one for Twilight Zone shows the same boards. The Driver board listing has J 133, 134 and 135 for lamp Rows, with 135-9 having the Red-grey wire of Row 8 coming from the cabinet (actually from the lamp socket, via D 1 of the Coin Interface). The lamp Columns use J 136, 137 & 139. 136 is only 3 pins, there was probably no need foreseen for more than one lamp column in the cabinet. If they're both in 136, that might be the problem.
 
I might be wrong about J136 to be honest. There is definitely a yellow-grey and red-grey wire in it (just two wires). I didn't (can't?) trace the wires all the way from the front of the machine up into the backbox because they go into a tube of wires.

Sounds like the best thing I can do really is get a whole mess of photos of everything I can see. :)
 
They're a Column wire and a Row wire in the same connector, then? The only small 3-pin one in that corner? Pin 1 of that, to the right, is a blank key (with no pin on the pcb), with pin 3 supplying Column 8 for the cabinet. I wonder if pin 2 is connected for Column 7*, though I can't imagine anyone needing more than eight lamp drives in a cabinet.

* after digging up my copy of the schematics, I see that it is, so having the cabinets' Row 8 wire in it will create a false connection between Columns 7 & 8 (via the Start button lamp), but only in one direction due to the diode, as @astyy thought
 
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I'll get some photos of everything tonight. I'm pretty clueless and I don't want to lead you down a path of thinking which is a waste of your time :)
 
Will get photos as soon as I can. Busy with work and slingshot breaking required my attention. :(
 
It may be a bad LED.
Incandescent lamps are basically a resistor that heats up in a glass gas bubble and glows, they don't have a positive or negative.

LEDs operate differently and have a positive and negative direction. The LEDs we use have a little trickery in the housing to enable them to operate however we plug them in.

If there is a fault in a LED it may still light but may also be causing a short.

Put the start button LED back in and pull any other bulb on column 7 or 8 and see if you still get the random lights.
 
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