Random LED flicker with thyristors in circuit simulation?

[DavidR357]

I'm working on a project, and am simulating the circuit in Circuit Wizard. I have a setup with transistors activating thyristors (see image).

The LED's are lit by a decade counter. The problem is every now and them (seemingly randomly) when a certain LED lights up, they all flicker. It is not the same LED, and it is not all the time. I do not know if there is a problem with the circuit, or if it is just the program creating this. Also, it is fairly common for LED's to be lit by a transistor with no voltage at the base (again, seemingly random).

The circuit may seem a bit odd in places (e.g. odd transistor placement), but it is not finished and everything there is needed. I de-cluttered it for this image, I replaced most of the circuit for switches (and this did not fix the problem).

The project is the arcade game stacker, but I want to try to make it without using a microcontroller. By this I mean that I want it to work via logic gates and counters within the circuit.

Just for reference, the 555 circuit is just an astable pulse generator, and the other chip is a 4017B decoded decade counter.

Thanks!

[Falcon69]

you may need to put a debounce circuit on those switches.

Also, I don't see a 0.1uF cap on the IC's power input.

[T3sl4co1l]

I see a couple things wrong with this, but I can't decide if it's the poor schematic layout or actually the circuit itself.

Can you reduce this to the simplest case, with just one or two row/col drivers or whatever?

And why would you choose thyristors at all?  For anything?

Tim

[Falcon69]

he's probably needs a latching thing done to them.  I was going that route before with another circuit I was doing. I finally said screw it and did Logic Gates / mosFET combination. (a different circuit then one you helped me out with Tim)

I had so many problems with those things, doing exactly what the OP is describing, random LED's lighting, that I just gave up.

[Zero999]

It can't be any layout or de-bouncing issues because he is talking about simulation, rather than the real thing.

He says he's using Circuit Wizard which is just an education program. I suspect that as well as poor design practise is to blame.

I suppose the question is: what is this supposed to do? There's bound to be a simpler, more effective solution, other than using a microcontroller or other programmable device.