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I've taken the board out, and have gone over it. No wrong resistors. Bear in mind that this is a copy of Dave Brown's build (and using his BOM), so there are some resistor changes - specifically R2 changed from 51K to 36K, and R51 is changed from 430 to 51K. There is also a 36K resistor added at pin 6 of U1. Would any of these make this effect? (Feel free to chime in, Dave, if you had a similar problem - probably not though)
- R51 muss 51K sein statt 430ohm430ohm - here its better to use a trimpot 100k and test value above 10K-100K
- R2 51k zu 36K
- 36K U1 pin6
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(by usage of the sin sharp trimpot - i cannot trim the " waveform like square" to a sin wave.. and its not 90degrees different.
Troubleshooting: 04.09.13
todo:
issue: same triangle at step 1.
test oscilloscope setting for trigger - maybe a triggersetting issue
test:
at U8 pin 1 - must have a triangle COS
at U8 pin 7 - must have a triangle SIN
both must have 90degree !
result: