Analysis this schematic

[georgi.g.zhelev]

mohandes . U 2A , U2 B (453 all is OK!! U3A, U3 B (453 no OK ! Chek C 9, R 14 ... C10, R 17 , trimer RV 5 .

# 133 , photo 1 pin6 , 5534 NO OK!

[mohandes]

do you think it is ok???????

[porkluvr]

Hi
this figure for wave of GND and pin6 ne5534.
mr porkluvr
i return multitern(discrimination)and sb dont change ,also sa and sb dont change when the output of 555 is changing.BECAUSE i am sure my problem in U3(second 453
you say maybe one 4148 destroyed but when in pin 9 second 4538 not output how is it work?

i put my picture step by step and waiting.
thanks

I don't know what your NE5534-6 should look like. I don't care what it looks like. You should concentrate on one problem at a time. Do you think you have a CD4538 timing problem?? I think you should WORK ON THAT, and fix it if it is broken. After that you can chase other problems.

SB is not supposed to change with DISC pot. SC will change but not SB.

If you view only a single pulse you will not see any change in SA SB or SC as you change either 555 PPS or 555 PW. If you would adjust the timebase control on the oscilloscope so that you can see more than one pulse at the same time, then when you change 555 frequency you should see a change in spacing between pulses... but you should really checking that at the 555 pin-3.

If you are concerned with the 555 potentiometers, then look at the 555-3 signal.

I don't understand why georgi had you probe at the start of the signal chain and then work to the end. I think that approach is exactly backwards for troubleshooting purposes. It only adds confusion and that is undesirable.

What I said before about looking at SA SB and SC still holds true. In my opinion, if those signals are good, then you do not need to look at all the other 4538 signals.

You should adjust the scope so that you can look at more than one cycle at the same time. That will give you a better overall view of the situation. If you want to diagnose a possible timing problem and you have your scope set to see only a single pulse, then you are wrong.

[porkluvr]

I was wrong to say that SC should not change with the DISC pot. SC is the (inverted) SA or SB logic function, and the disc pot changes SB directly. Therefore turning the DISC pot should change SC.

Somewhere in the back of my mind that previous statement did not seem right.
(I need a long vacation.)

[mohandes]

mr porkluvr
please measure pin2,pin14 for U2 ,U3 and put it here,and pin6,7,9,10 U3,please
thanks

[porkluvr]

mr porkluvr
please measure pin2,pin14 for U2 ,U3 and put it here,and pin6,7,9,10 U3,please
thanks

I see that, instead of being mid-position, my (LTspice) 555 PPS pot is set to high PPS, and pulsewidth is set to long PW. Earlier today I tried setting those controls to mid-position but the simulation ran for only 2 milliseconds and then wanted to hang. I have 'dialed' the pots back to where they were, high PPS and high PW. Such is life. I do not have time to troubleshoot that virtual hang-up.

Here's an important note: I had the resistance on U3-2 on mislabeled, calling it discriminate by mistake. The discriminate pot is connected to U3-14. I apologize for the mistake.

I have some chores to do. I'll try to post your signals when I get back.

[mohandes]

I see that, instead of being mid-position, my (LTspice) 555 PPS pot is set to high PPS, and pulsewidth is set to long PW. Earlier today I tried setting those controls to mid-position but the simulation ran for only 2 milliseconds and then wanted to hang. I have 'dialed' the pots back to where they were, high PPS and high PW. Such is life. I do not have time to troubleshoot that virtual hang-up.

Here's an important note: I had the resistance on U3-2 on mislabeled, calling it discriminate by mistake. The discriminate pot is connected to U3-14. I apologize for the mistake.

I have some chores to do. I'll try to post your signals when I get back.

ok i am Waiting
thanks

[porkluvr]

ok i am Waiting
thanks

I'm still working.

I took another look at the top foto in post 137. You might be right about there being a mistake. The wiper should not be connected to ground unless the 4.7kΩ resistor is moved to the bottom side (pin-1) of the potentiometer.

My copy of a Fairchild CD4538 data sheet implies that the minimum resistance on either pin-1 or pin-15 is 5.0kΩ. Jumping across the 4.7kΩ from the pot's wiper would render about 1/3 of the pot travel unusable.

[porkluvr]

Here you can see the signals on the 4538 'RC' pins.
They are in the order U2-2, U2-14, U3-2, U3-15. Discriminate pot has been MOVED to its correct location, set at 50%.

Now, these RC sigals do not tell me very much but since you wanted to see them, here they are.

After having realized I had the discriminate pot at the wrong location, now I need to sit back and take another look to figure out what it does. Oh, happy day.

[porkluvr]

Here are SA, SB, and SC. I think they're correct this time.

As the discriminate pot is moved, SB and also the right half of the SC signal will move.

[mohandes]

Here you can see the signals on the 4538 'RC' pins.
They are in the order U2-2, U2-14, U3-2, U3-15. Discriminate pot has been MOVED to its correct location, set at 50%.

Now, these RC sigals do not tell me very much but since you wanted to see them, here they are.

After having realized I had the discriminate pot at the wrong location, now I need to sit back and take another look to figure out what it does. Oh, happy day.

FIRST i say thank you very much and for professional design ,i see the pot discrimination and in my pcb is correct i n#143 (like alexis)ok i set it on 5K.
and this is my analyse:
for U3 in1,4,8,12,15 are -10.6v and always Fixed and pin3,13,16are Fixed and 0volt, and pin9 not connection and pin 11 is Fixed.SO THESE PINS HAVE NOT ERROR

so remained pin2,5,10,14,6,7 and for this pins:
if pin2,5 not well work have mistake ok!!so pin6and pin7 not good so have fault,BUT HOW?when all correct for example cb ok,components ok ,voltages ok,but yet pin6,7,9,10 not have pulses,
IF you can and dont tired and dont angry put measure waves of pin6,7,9,10 and again i go and check,
just i say so sorry because i am confused i check all but when measure not out put (or maybe ok and i am not ok)
thanks
this picture of pin2 &14 pcb but have not good Quality

[porkluvr]

!

[Davor]

Last time I played with 4538s in LTspice they were incredibly slow to converge. Do you maybe have some more cooperative models?

[mohandes]

HI ALL GURUS
i find my BIG PROBLEM this is in pin14, should change multi turn by resistor like #143 .
i have frequency in pin6,7,10,9 U3(measure by multimeter and about 140Hz),for i am SURE about these, i should measure by scope in collage 2 days latter.

I SAY THANKS GURUS AND FRIENDS:Mr porkluvr ,Mr Davor, Mr georgi ,Mr Tepco,Mr carl
but i measure by scope 2 days latter for becuase i SURE about them.

[porkluvr]

Last time I played with 4538s in LTspice they were incredibly slow to converge. Do you maybe have some more cooperative models?

I'm pretty sure we both have the same model, from CD4000.lib (?). Mine runs pretty slow but not bone-jarring slow. With four OSs in this circuit this simulation slows down to about 6 us/s when the one-shots start "calculating". That is acceptable to me.

I am using my old 1.8GHz Athlon XP2500+ dinosaur, 2Gb.

Make sure you change the "SpiceModel" field to reflect the names of both power supply rails. Ground being called "0" has always worked for me.

SpiceLine "VDD=" should state the absolute value of (V+ - V-) (of course).