Yahoo Groups archive

Cgs synth

Index last updated: 2026-04-28 23:16 UTC

Message

Re: Debugging Gate Sequencer

2007-07-28 by The Alison Project

Alright I figured out my Hold problem, defective toggle (my first one haha)...

As for the Reset, no luck.... Parts are correct, I tried replaced the 100K with a 330K like you suggested and nothing....

This is a V1.4 board, on the schem (earlier version) after the 15K there is a diode, 100k res, 100n cap marked *not present on earlier PCB. It does not appear to be on this version, only other difference I see is at the reset input pad there is a diode going to +15V....

Also I am not using the Disable Jack and have installed the diode afer its pad on the pcb....

hmmmmm


----- Original Message -----
From: sasami@...
To: cgs_synth@yahoogroups.com
Sent: Friday, July 27, 2007 10:21 PM
Subject: Re: [cgs_synth] Debugging Gate Sequencer


First, I suggest that you have a parts installation error around the reset
input. Failing that:-

>My reset jack will reset with a gate of approx 10V, the 5V gate outs of say
my Sequential Swicth will not reset the module.

It should be sensitive to around 2 volts. Try increasing the value of the
100k from pin 3 to earth to 330k.

>In Hold mode it is not working correctly, with a sequence of 8 steps when I
change it to Hold mode it will just loop between 2-8, and as I change
sequence length it will loop between smaller amounts... Every now and than
when I change the sequence length it will work correctly for a second.

behavior wne actually rotating the switch can be eratic.

>I am using a LM358 on the main board, I tried a few TL072cp and I cannot
get the 4017 to clock at all with the TL072.

Try different LM358 or other op-amps. If you can only get TL072, disconnect
its pin 4 and connect it to -VE instead of 0V AND add a diode between pin 7
of the TL072 and pin 14 of the 4017, cutting the track (i.e. put the diode
in series, cathode towards the 4017). Add a 100k from pin 14 of the 4017 to
0 volts.

>I've swapped out the 4017 for another althou all I have on hand is CD4017BE.

Nothing wrong with those 4017.

Ken
__________________________________________________________
Ken Stone sasami@...
Modular Synth PCBs for sale <http://www.cgs.synth.net/>
Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>





[Non-text portions of this message have been removed]

Attachments

Move to quarantaine

This moves the raw source file on disk only. The archive index is not changed automatically, so you still need to run a manual refresh afterward.