Bally Bow and Arrow pop bumper issues

Hi all, so I've been slowly bringing this game back to life, and apart from a few minor issues I can't seem to get all pop bumpers to work. The bridge rectifier checks ok. Not sure about the capacitor as I don't know how to test. No diodes on the pop bumpers when I got the game-weird. Added the correct diodes, and the two center pops have no power. Did a continuity test from the bridge rectifier to all the pop bumpers and checked out.
Any ideas as to why there's no power to the two pop bumpers?

#2 1 year ago

???

hjh632

Pinside member

5y 47,050 799

You probably checked, but are the diodes oriented correctly?

Did the bumpers work before you put the diodes on?

#3 1 year ago

DAD

phergott

Pinside member

I believe I oriented them correctly. I have my friends' bow and arrow right next to mine. Only the two that are working-very weak w/o the diodes. They're(the two working ones), much stronger now.

#4 1 year ago

DAD

phergott

Pinside member

Okay, I compared the readings with a dmm with the properly working bow and arrow and mine. Each leg of the bridge rectifier to both legs of each pop bumper coil and readings are identical. The diodes tested good too. Still no power to the two center pop bumpers. Suggestions anyone?

#5 1 year ago

MarkG

OP
Quoted from phergott:
Added the correct diodes

What are the correct diodes? They're not mentioned on the schematic. Should they be there? The capacitor might be all you need to absorb the voltage spike when the coils shut off. SS games require coil diodes to protect the low voltage devices (chips) but EM games don't have that sensitivity. If the diodes are installed the wrong way they would provide a short around the coil and effectively disable it. If they're necessary the bands on the diodes should be connected to the 70/orange/positive wire on the coil lug.

If the diodes aren't the issue the circuits for the pop bumpers and sling shots are all identical:
Bow and Arrow Pop bumpers (resized).jpg

If just the A and B pop bumpers aren't working I'd have a close look at the wiring to those two bumpers. Maybe there's a break or bad solder joint.

If you jumper a non working coil (like the A bumper) to a working coil (like the C bumper) do they both work when the working bumper activates? That would be a way to prove that the coils are good.

If you jumper across the A or B bumper switches do their coils fire? That would prove that there's power at the switch.

/Mark

#6 1 year ago

DAD

phergott

Pinside member

Hi Mark, thanks for your reply. So I jumpered the pop bumpers as you suggested and no power to A or B pop bumpers. Then pop bumper D isn't working. I then swapped out the proven good bridge rectifier from my friends game and still, A and B don't work. To top it off, when I put the good bridge rectifier back in his game, none of his pop bumpers worked! -like the rectifier was wrecked. So something is obviously going on with the wiring with mine.

#7 1 year ago

MarkG

So you jumpered A to D and D stopped working? That could be that the diode you added to A is in backwards. It provides a bypass or short circuit around the A pop bumper and when you connect it to D it provides a bypass around D too. The current of the short might have damaged your rectifier.

How did you identify what diodes to use? Have you tried lifting one leg of the diodes to see if it works without them?

#8 1 year ago

DAD

phergott

Pinside member

All the bands of the diodes are facing the orange wires. I identified the diodes as IN-4004 as shown in other Bally em schematics. I then removed same diodes as identified from an old Count Down SS wire harness. The diodes measured .54-.56. I didn't try lifting one leg of the diode yet as the bridge rectifier is/was burned out.
I'll have to order a new rectifier before I can continue troubleshooting. I'll start with the diodes removed first thing. I'll report back when I get the new rectifier. Would happen to know the spec of the bridge rectifier?

#9 1 year ago

MarkG

I don't know the rectifier specs. The rectifier is probably getting about 55 volts AC from the transformer and there's a 5 amp fuse in the circuit to the DC coils. Those would be the absolute minimum required values for voltage and current capacity. Rectifiers are cheap. I'd go 5x-10x those values for plenty of margin. Consider ordering an extra since you haven't really sorted out the issue yet. See https://www.greatplainselectronics.com/products.asp?cat=172 for some examples.

#10 1 year ago

DAD

phergott

Pinside member

Great! Thanks Mark.

1 week later

#11 1 year ago

DAD

phergott

Pinside member

Okay, first off for everyone's info, Great Plains Electronics temporarily/permanently closed(read their homepage).
So I got a couple of rectifiers from Amazon, and installed in the game. Before powering up, I removed the diodes from the pop bumpers and then powered up and started a game. The A and B pop bumpers still didn't work. There was a buzz in the backbox(probably the 10 pt relay), that I let run for about 10 seconds, and the D pop bumper switch caught on fire, melting the plastic spoon-yikes!! That was yesterday. Had to walk away. This morning I first checked continuity from the coil tabs individualy orange wire to the rectifier, and all readings checked out compared to the other Bow and Arrow. Next, with the power on, I clipped one end of the jumper cable to the C(working) pop bumper white/green switch tab and with the other end of the jumper touched the grey switch tabs of the other pop bumpers. They worked! I then proceeded to do the same with the other pop bumpers. A to B, C, D and so on. I'm stumped.

#12 1 year ago

MarkG

OP
Quoted from phergott:
There was a buzz in the backbox(probably the 10 pt relay), that I let run for about 10 seconds, and the D pop bumper switch caught on fire, melting the plastic spoon-yikes!!

I'd unwind what's going on there. What relay, and how is it connected to the pop bumper? According to the schematic above the pop bumper switch should should only be wired to the rectifier, capacitor and the pop bumper coil. You may have a short between the AC and DC circuitry.

Visually check the wiring between the two games to look for any alterations.

You might watch the DC voltage across the capacitor when the various pop bumpers fire. Does it behave the same for all four or do the two non working pop bumpers drop the voltage more?

#13 1 year ago

DAD

phergott

Pinside member