sorry for the delay in trying this out
I just went back and replaced all the transistors on both 2 and 3 stages and stepping now works in both directions. probably a bad one in there somewhere.
The buttons are still no go, checked the B line, and it WAS way below 7.5v due to the fact that i was trying to run it at 12v.
I reconfigured my power supply to run at 15v and B line now runs at 7.55v but still no dice with the buttons.
diodes all oriented correctly, no problems there.
Interesting observation here when i push the button, the B rail drops to 6.7v. not sure if that is expected behavior or not.
I just went back and replaced all the transistors on both 2 and 3 stages and stepping now works in both directions. probably a bad one in there somewhere.
The buttons are still no go, checked the B line, and it WAS way below 7.5v due to the fact that i was trying to run it at 12v.
I reconfigured my power supply to run at 15v and B line now runs at 7.55v but still no dice with the buttons.
diodes all oriented correctly, no problems there.
Interesting observation here when i push the button, the B rail drops to 6.7v. not sure if that is expected behavior or not.
--- In cgs_synth@yahoogroups.com, "cg_synth" <sasami@...> wrote:
>
> First, check your "B" line is at 7.5 volts. If it isn't, that is why your buttons don't work. The B line puts the voltage on one side of the switches. Also check each push button connects to the cathode of its two diodes.
>
> As for the step 3 failure, the problem will be one board 3 (Check around the PNP transistor pair, and connections F and J) or board 2 (trace from "H" to make sure it actually connects to the rest of the circuit on board 2 - no broken traces or whatever).
> Ken
>
> --- In cgs_synth@yahoogroups.com, "ch1nard" <steve.benesko@> wrote:
> >
> > I've been building a SWAMP pannel and i've pretty much got most of the CGS59 functions working with a couple of exceptions that i just cant seem to figure out.
> >
> > First is pretty easy to explain, pushbuttons dont seem to work.
> > I've gone over all the buss connections plus double checked all the diode orientation.
> > The pulse inputs are all working fine, so i have a feeling i am missing something really obvious and stupid.
> >
> > The other problem is a bit of a weird one, but i'm sure is easy to solve.
> > So applying pulse UP works great. Able to step through all 8 stages and wrap around again.
> > Applying pulse DOWN stops on stage 3 and will go no further.
> > I've gone through and triple checked all the buss connections as well as the G/H/J wiring. It does work in one direction so i am thinking the problem might be somewhere in or near the pulse generators on the A boards.
> >
> > oh btw.. these are the earlier revision boards (non-rohs) the one where you have to reverse the orientation of the BC547 on the A boards and install that 1M+1N4148 in chain.
> >
>