Open rafael-azevedo opened 1 year ago
Adding two videos of it working. In this one with it in the unlocked position you can see if always hit the same voltages https://youtube.com/shorts/sOzEx5lxdU0?feature=share
a video of it with a "scope" view
posted pictures here of the build https://modwiggler.com/forum/viewtopic.php?p=3995928#p3995928
bump
The pictures look OK, was this built from a Thonk kit?
One think to try would be to swap the two 4015 shift register chips and see if the behaviour changes
I am pretty sure its a thonk build. I picked it up second hand. It was working as expected before shipping. I swapped the two chips and the behavior stayed the same.
Hi Rafael,
I think you should return it and get a refund or insist that the seller repairs it for you.
Regards
Steve Thonk
On Fri, Jul 14, 2023 at 2:03 PM Rafael Azevedo @.***> wrote:
I am pretty sure its a thonk build. I picked it up second hand. It was working as expected before shipping. I swapped the two chips and the behavior stayed the same.
— Reply to this email directly, view it on GitHub https://github.com/TomWhitwell/TuringMachine/issues/202#issuecomment-1635834822, or unsubscribe https://github.com/notifications/unsubscribe-auth/AAKXH6EST7GFYOAAO6DKEULXQE7SFANCNFSM6AAAAAA2F65DNI . You are receiving this because you are subscribed to this thread.Message ID: @.***>
Ya I worked out a deal with the seller already. Just trying to see if I can troubleshoot whats up. I ordered new IC chips if those don't work I'll just do a new build haha
Ok glad to hear that, there are some sellers who seem to think a buyer should inherit their build problems :)
On Fri, Jul 14, 2023 at 3:17 PM Rafael Azevedo @.***> wrote:
Ya I worked out a deal with the seller already. Just trying to see if I can troubleshoot whats up. I ordered new IC chips if those don't work I'll just do a new build haha
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Any other recommendations on troubleshooting before I give up. I've replaced all the ICs outside of the DAC and the noise trimer pot and its still exhibiting the same behavior
Seems I have isolated the issue. The voltage out is not matching the bits in the shift register. If I understand correctly they should be multiples of 0.033v but I am getting 0.3V with 1 bit in the first position video attached explaining
Maybe something wrong around the resistors in the op amp that scales the output? Maybe if R26 was 50k or 500k you'd see this behaviour? Just a guess, I've never seen this before, and it would only explain incorrect voltage output, not incorrect sequences of bits.
Yup looks like there was an incorrect resistor for R26 I replaced it and had to jump it to p1 of the TC074. Now I am getting a new behavior where sequences longer then 5 don't work as expected https://youtube.com/shorts/4pj9n4bUo6s?si=-Ana2UskU1RuRxdt
I was able to calibrate the turing machine so the locking feature works. The issue I am having is that I always get a similar sequence a small ramp up from 0 in steps and then it holds the highest value set by the trim pot for a while and repeats. Now it does this randomly , but I never get step down or anything of that nature.