[sdiy] sequencer ideas

[Brockr0 at cs.com]

In a message dated 6/2/01 mitch at sirius.com writes:

>     I built that sequencer at the link you have there. It works pretty
>  well and was not hard to make on generic PCB from radioshack.
>  
>      I had a problem with it and asked the list for some suggestions and
>  someone pointed out that there were some problems with the circuit in
>  the reset pulse input and one of the pins is not wired correctly on the
>  4516 chip. I can't remember what this was though.
>  
>      I have another Schematic that goes with this one that shows how to
>  wire LEDs or an 8 segment display to the seq8 circuit.
>  
>  http://www.webdevils.com/schematics/seqdisp.jpg
>  
>      I can't remember where I found these schematics, so I posted them to
>  my site. There was also some suggestions to use the enable pin of the
>  4051 and the 4th bit of the 4516 to chain two of these together.
>  
>  --M

Seems to me I replied to Mitch originally but I don't have that reply and the 
list was down then so it's not in the archive...

I thought there were three problems with the circuit but can only see two now:

1 - TC pin 7 is an output but it is tied to ground. It should be open.

2 - G3 pin 2 is an output that gets pulled high through a transistor - not 
good.
It should be open as it also stops the counter from cycling in down count 
mode by keeping it reset.

The third thing might have been that the 100k resistor is redundant.