(Topic ID: 158295)

Mystery Extra Bridge Rectifier

By Cheddar

5 years ago



Topic Stats

  • 10 posts
  • 6 Pinsiders participating
  • Latest reply 5 years ago by barakandl
  • No one calls this topic a favorite

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#1 5 years ago

So the Alien Poker I am resurrecting has a bridge rectifier on the GI circuit. Any idea what they were thinking?

Please note: the wire I'm holding is woven in the mix but is unrelated. It goes to the terminal to the left of the gi fuse.

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#2 5 years ago

I removed it and everything works fine so who knows! Marking as resolved

#3 5 years ago

Does the GI have LEDs in it? Might've been converted to DC in an attempt to avoid LED flicker...

#4 5 years ago

May just be there to slightly reduce the voltage, I've seen that done in DE games. Makes the bulbs last longer.

#5 5 years ago
Quoted from yendor0:

Does the GI have LEDs in it? Might've been converted to DC in an attempt to avoid LED flicker...

No LEDS

Quoted from johnwartjr:

May just be there to slightly reduce the voltage, I've seen that done in DE games. Makes the bulbs last longer.

The GI is brighter without it! Good call. Basically a big old expensive resistor huh?

#6 5 years ago

Actually the AC voltage should increase when rectified to about 8.9VDC

#7 5 years ago
Quoted from Cheddar:

The GI is brighter without it! Good call. Basically a big old expensive resistor huh?

Careful about that--more voltage also means more heat, and possibly burned headers & connectors.

Also, be sure to look through this: https://pinside.com/pinball/forum/topic/vids-guide-to-bulletproofing-williams-system-6

#8 5 years ago
Quoted from LEE:

Actually the AC voltage should increase when rectified to about 8.9VDC

It's not done in a traditional way in the application I described.

From Clay's guide:

Using a bridge rectifier to decrease the GI voltage. This will dramatically increase
bulb life. Here the yellow/white GI wires from the transformer are fed to the
modified bridge rectifier "+" and "AC" lugs. Then a jumper wire goes from the
"+" to the "-" lug, and the two "AC" lugs are jumped.

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#9 5 years ago

This was only half way done on my machine. The GI line (singular) went through the BR but the other 2 lugs were wide open. This game looks routedd (note the double d for a double dose of it's pimpin) hard so this was probably done to save bulbs and keep the lights on.

#10 5 years ago

the voltage drop across the diodes in the bridge will reduce the voltage as the voltage drop is burned off as heat, i would for sure heat sink this application.

If you see the big power diodes on the squawk and talk board and even the cheap squeak. They run the 12v through a few power diodes just to get that voltage drop across each diode. They wanted to burn the heat off some extra heat at the diode instead of the regulator. Too bad on the squawk and talk sound board, those diodes just dry up the 10uF cap above them and cause more problems than the diodes where trying to fix.

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