4017 based sequencer: voltages wont hold

Seriously, is this a test for the rest of us?

with all that you have done, it's obvious that C12 is going to block the DC from the ramp level..

You need to remove that and tailor the R's in the input to balance the circuit.

But you most likely already knew that any ways!

Seriously, is this a test for the rest of us?

with all that you have done, it's obvious that C12 is going to block the DC from the ramp level..

You need to remove that and tailor the R's in the input to balance the circuit.

But you most likely already knew that any ways!

C12 looks as if it was the bad idea. If you want Vout to be held indefinitely, remove C12. and connect R16 directly to the emitters of T11 and T12 as well as R6.

I imagine that C12 was originally intended to be connected to the other end of R16 (the common point with R16, R17 and IC5/3, with the other end returned to ground to slow down the transitions at Vout.

I've not looked at the circuit for long enough to have much idea of what it is supposed to be doing, so there could be other strange connections.

-- Bill Sloman, Nijmegen

Thanks Bill - yes, in retrospect C12 was a bit stupid of me! I'll short it out and see if that fixes the problem.

Also it seems I have R17 and R18's values the wrong way around.

Thanks again. Julian

As I said, I couldn't see the wood for the trees ... no test - I had spent too long in Spice and my brain was fuddled :-)