after a short into the main line of current ,ly shruti first generation with smr4 board ,have somes issues
first the screen are frozen ,now it’s fixed with the help of forum user and the mains shematics ,thank you !
but now i see an other problems on the filter the resonance doesn’t work correctly .
i have searched the schematics but i not found ,i have found only the “checking sound on filter board”
Do you have any schematics for search where this issue begin ?
or do you have an idea of this problem ?
thank you so much for your help
There should be an audio signal corresponding to increasingly filtered versions of the oscillators signal on pins 14, 1, 7, and 8 of the TL074. Is that the case?
i hear signal on each pin
The signal at pin 7 of IC4 should be silence when resonance is set to 0, and its level should increase as you increase resonance. This signal should be affected by cutoff.
yes the signal increse and decrease if i turn cut and res pot
but i have tested remove ic5 and connect 10k on pin 1 and -5v
res 0 = 5.02v
res 63 = 3.56v
that’s correct for the lm13700 ?
thank you sir
fixed the problem it’s on the lm13700 i have changed them and no working
You cannot check resistances in circuit.
It takes 22 turns to reach the end of the trimmer. When it reaches the end, it emits a faint click and is slightly more difficult to turn. Try temporarily shorting the 2 extreme pins of the trimmer. Does it improve resonance?
Put the pole selector to 4 pole, since resonance is more emphasized in 4-pole mode.
ok i have tested ,in two position
Have you adjusted the resonance trimmer? Is it correctly soldered?
i think i have a problem with us ,no click at the end when turn clockwise ,
do you think i can test it on the board ,what value i can read normally ?
i check the voltage of Q
reso 0 = 0.12 mv
reso 63 = 4.91 v
i continue to check the other way
Post a photo of your board, we’ll see if you have swapped resistor values…