Author |
Message |
koenpepping
Joined: Jun 25, 2014 Posts: 8 Location: utrecht NL
|
Posted: Fri Jul 25, 2014 7:01 am Post subject:
Need some help LFO trimming (scope photos included) |
|
|
Hi,
I am trying to trim my yusynth LFO, but it doesn't seem to work really well. (scope y is divided by 5v)
I've tried a lot but:
The LED is always on, it doesn't blink
The triangle looks more like a saw
Pulsewidth is varies from 0% to 10% (as you can see on the picture)
Sine doesn't really look like a sine (see picture)
what can i do?
thanks!
Description: |
|
Filesize: |
600.81 KB |
Viewed: |
471 Time(s) |
This image has been reduced to fit the page. Click on it to enlarge. |
|
Description: |
|
Filesize: |
751.63 KB |
Viewed: |
359 Time(s) |
This image has been reduced to fit the page. Click on it to enlarge. |
|
Description: |
|
Filesize: |
764.39 KB |
Viewed: |
379 Time(s) |
This image has been reduced to fit the page. Click on it to enlarge. |
|
Description: |
Pulse (on maximum pulsewidth, minimum is just a flat line) |
|
Filesize: |
763.17 KB |
Viewed: |
368 Time(s) |
This image has been reduced to fit the page. Click on it to enlarge. |
|
|
|
Back to top
|
|
|
Andrej
Joined: Aug 25, 2016 Posts: 1 Location: Lithuania
|
Posted: Thu Aug 25, 2016 1:16 pm Post subject:
|
|
|
hi everyone.
I know this topic is old, but same problems remain. i've got the same trimming problems. and my LFO2 oscillates at very high frequency, just like VCO. I used ICM7555 , TL071 and TL074. all parts were checked before soldering and all voltages are ok.
any help please? |
|
Back to top
|
|
|
yusynth
Joined: Nov 24, 2005 Posts: 1314 Location: France
|
Posted: Tue Sep 06, 2016 1:25 am Post subject:
|
|
|
Are you sure you used a BC557 (PNP) for Q1 ?
For your scope shot what is the amplitude (V/square) and time scale (ms/square) ? _________________ Yves |
|
Back to top
|
|
|
RyBowk
Joined: Nov 25, 2018 Posts: 33 Location: England
|
Posted: Mon Nov 18, 2019 3:46 am Post subject:
|
|
|
I have the exact same issues as this, does anyone know the solutions at all yet? I have replaced all ic’s, transistors, caps. No change. My scope images are exactly the same as these. I am powering at 12v by the way many thanks Ryan |
|
Back to top
|
|
|
|