Need some electronics Help - Big Choice Marquee lights

Teknotoyz

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Need some electronics Help - Big Choice Marquee lights

I had purchased this crane 2 years ago, it had no sound and a separate lamp board that flashed the lights in a chase pattern.
Recently, I purchased a newer crane (same style) that has the sound and display.
There also was no marquee light display (lamp board was not connected)
The plan was to swap the internal boards to update my existing crane.

I also had no desire to repeat this:
DSC03760.jpg


Once I got everything set up, the Marquee lights just flash on/off, no chase sequence at all.
I checked the "Winner" output, and it is also flashing in unison with the lights.
There are 4 "zones" and 1 "Winner" output.

From what I can tell, by the blurry schematics, the 120v circuit is on the lamp side only.
The main board supplies ground and 5v for the logic, and a "trigger" which I assume is the "Winner" light output.

I tried adjusting the "Lamp Speed" and the flashing just speeds up or slows down, again all lamps are flashing in unison.

So my question for those that know the electronics better, what should I check first?
My guess is that U5 looks to be the likely cause.
Is U5 a programmed chip? looks like "PROM" is on the schematics.
If so, any idea on where to obtain a new PROM?


DSC03803.jpg


IMG_4740.jpg


ScreenShot2012-02-19at61009PM.png
 
Bump for the day crowd.

Another question, Betson said the PROM is no longer available (no surprise there).
Is there any way to "read" a program from a good PROM to reburn one?

I may be barking up the wrong tree, not sure what else would create the chase sequence.
IMO, the fact that all the lights ARE blinking means the 120v components are functioning.
 
Wow that is blurry...but I'll take a stab...

Chances are, the blinking is maybe the CPU driving the prom via pin 14...maybe it always thinks its in "win" mode. You can remove and gently bend out pin 14 of the prom, replace (without pin 14) and see if that brings back the chase mode. If you look, the 4075 @ U2 takes 3 signals and translates that into one signal that probably changes the behavior of the prom (blink vs chase?). You'd have to look up the 4075 to see if its working right (compare the inputs to the output).

If you do isolate pin 14 of the prom and the lights stay solid on, check pin 2 at the 74LS163 for a pulse (if you have a logic probe). The 163 is a counter...that little circuit with the speed pot should be making a pulse that triggers the 163 to count out a binary pattern to the prom which then translates that pattern to the chase pattern. If there's no pulse, it no count, and the lights just stay on (or stuck at a certain pattern).

If it were me I'd also replace that electrolytic cap there...looks like it's seen some heat.

FYI, so you're careful, the SC146D's, (in fact everything over the 6 pin dips (optocouplers)) are the 120v portion, they are triacs that act like relays to turn the bulbs off and on, so at least one pin of each of those has 120v going to it. The optocouplers basically enable the low voltage side to control the high voltage side without physically being connected to each other.

PS - to answer your question, yes if someone had a known good prom, it could be read/copied but you need a prom burner, which many rom burners do not support.
 
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Update:

I got a replacement light board off Ebay and the flashing that the first board was doing is indeed the "Win" sequence.
I never did try to repair it, but the crane is now fully working as it should with the new board!! (Cost me $8 shipped)
I installed a sensor and the machine now plays a music tune and flashes the lights when someone wins....

I like it!! :D
 
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