Help with Bill Bowden Game Show Who's First Circuit

[Ariel Suero]

I really need your help. I embarked on assembling one of the circuits posted on the page, specifically the Game Show Who’s First Circuit. I purchased the parts and put it together to what I understand is correct. Here is what I’m seeing.

With a setup of a total of 6 stations, but with only 2 connected for test.

1.The relay clicks to trigger the buzzer.
2.When a button is pushed, it turns on it’s corresponding light.
3.The reset switch works.
4.I added a power switch, which does route power to the circuit or not.
5.Added a fuse to the system before the reset switch.

Problem: When station button is pushed a 2nd can also power it’s light. Essentially it isn’t locking out the other stations.

I tried checking if maybe the button pushes were too close together in timing that it might light both, but with delay in between pushes the test setup lights either way.

Does it need the minimum 3 stations in order to work properly? I suspect that it shouldn’t matter how many stations are wired it should still lock them out. If you could please give me some guidance it would be greatly appreciated. I’m kind of stuck and not sure where to proceed.

Thank you

Ariel

 

[Dan Coby]

On 6/22/2013 11:08 AM, Ariel Suero wrote:

I really need your help. I embarked on assembling one of the circuits posted on the page, specifically the Game Show Who’s First Circuit. I purchased the parts and put it together to what I understand is correct. Here is what I’m seeing.

With a setup of a total of 6 stations, but with only 2 connected for test.

1.The relay clicks to trigger the buzzer.
2.When a button is pushed, it turns on it’s corresponding light.
3.The reset switch works.
4.I added a power switch, which does route power to the circuit or not.
5.Added a fuse to the system before the reset switch.

Problem: When station button is pushed a 2nd can also power it’s light. Essentially it isn’t locking out the other stations.

I tried checking if maybe the button pushes were too close together in timing that it might light both, but with delay in between pushes the test setup lights either way.

Does it need the minimum 3 stations in order to work properly? I suspect that it shouldn’t matter how many stations are wired it should still lock them out. If you could please give me some guidance it would be greatly appreciated. I’m kind of stuck and not sure where to proceed.

You are correct that the number of stations is not critical to the operation of this circuit.

Comments:

BE VERY CAREFUL WITH THIS CIRCUIT. There is no isolation between this circuit
and the 120 volt main supply. Besides having 120 vac present, the bridge rectifier
is also creating 169 volt DC. Debugging this circuit is a real shock hazard.

It would have been nice to have given a link to the circuit instead of forcing
people to search for it. You are more likely to get comments if people do not
have to guess about which circuit you are actually using.


Debugging:

If I were trying to find a problem in this circuit, this is what I would do:

1) BE CAREFUL. Please note my previous comment about this circuit being a
shock hazard.

2) Remove the relay coil and the diode next to it for now. These are simply
added complications and can be a problem if either is bad.

3) Recheck all of the wiring connections. (Note: The circuit diagram shows
some breaks in a wire in a couple of places where other wires cross. All
three of the 2K resistors should have their bottoms connected together.)
Also check all of the component values. For instance your circuit has both
51 ohm and 51 kiloohm resistors. Make sure that you are using the correct values.

4) Check that you have 120 vac on the input the bridge.

5) Check that you have about 169 volt DC across the 100 uf capacitor on the left
side of the circuit diagram. A 10% variation is expected.

6) With none of the 25 watt lamps lit, check that you have about 3 volts DC
across the 1k resistor on the left side of the diagram. (Component labels
on the circuit diagram would have been nice. Yes I know that is not your fault.)

7) Press a button to light a lamp. Check that you have about 10 volts DC
across the 51 ohm resistor shown next to the relay. Since this voltage is
higher than the 3 volts on the 1k resistor, this should keep the other lamps
from lighting.


Dan

 

[Ariel Suero]

On Saturday, June 22, 2013 2:08:18 PM UTC-4, Ariel Suero wrote:

I really need your help. I embarked on assembling one of the circuits posted on the page, specifically the Game Show Who’s First Circuit. I purchased the parts and put it together to what I understand is correct. Here is what I’m seeing.



With a setup of a total of 6 stations, but with only 2 connected for test..



1.The relay clicks to trigger the buzzer.

2.When a button is pushed, it turns on it’s corresponding light.

3.The reset switch works.

4.I added a power switch, which does route power to the circuit or not.

5.Added a fuse to the system before the reset switch.



Problem: When station button is pushed a 2nd can also power it’s light. Essentially it isn’t locking out the other stations.



I tried checking if maybe the button pushes were too close together in timing that it might light both, but with delay in between pushes the test setup lights either way.



Does it need the minimum 3 stations in order to work properly? I suspect that it shouldn’t matter how many stations are wired it should still lock them out. If you could please give me some guidance it would be greatly appreciated. I’m kind of stuck and not sure where to proceed.



Thank you



Ariel

So, after carefully reviewing the schematic and my circuit, I found that the resistor that should link the SCRs was not wired correctly. I suppose long nights setting up this system and tending to a 9 month old scrambled my brain. Thanks to all!!!