What do the symbols in the red circle mean?
Here are two logic symbols of the dual 4-channel analog multiplexer/demultiplexer 74HCT4052:
The second one is according to the IEC standard.
Here a snippet from the data sheet:
General description
The 74HC4052; 74HCT4052 is a dual single-pole quad-throw analog switch
suitable for use in analog or digital 4:1 multiplexer/demultiplexer applications. Each
switch features four independent inputs/outputs (nY0, nY1, nY2 and nY3) and a common input/output (nZ). A digital enable input (E) and two digital select inputs (S0 and S1) are common to both switches. When E is HIGH, the switches are turned off.
You can download the full datasheet here.
Thank you.
The reason I asked was that pin 9 of IC1 is showing 0V rather than the 3.3V required and I was trying to work out where connections were ti other components.
I am very much a novice at electronics.
Regards
There should be 0V when the USB cable is connected but the PC software EDU09 is not running.
There should be 3.3V when the USB cable is connected and the PC software EDU09 is is running.
Is this the case, or is there all the time 0V on pin 9?
Here are the voltages measured on all IC2 pins:
These voltages are measured when the USB cable is connected but the PC software EDU09 is not running.
1: 1.76V
2: 0V
3: 0V
4: -5.2V
5: 0V
6: 0V
7: -1.65V
8: 5.0V
On IC1 pins the voltages should be:
1: 0V
2: 0V
3: 0V
4: 0V
5: 0V
6: 0V
7: -5.2V
8: 0V
9: 0V
10: 0V
11: 0V
12: 0V
13: 0V
14: 0V
15: 0V
16: 5V
These voltages are measured when the PC software EDU09 is running.
Here are the voltages measured on all IC2 pins:
1: 1.65V
2: 0V
3: 0V
4: -5.2V
5: 0V
6: 0V
7: -1.65V
8: 5.0V
On IC1 pins the voltages should be:
1: 0V
2: 0V
3: 0V
4: 0V
5: 0V
6: 0V
7: -5.2V
8: 0V
9: 3.3V
10: 0V
11: 0V
12: 0V
13: 0V
14: 0V
15: 0V
16: 5V
Hello again,
When the USB is connected but not running IC1 and IC2 readings are correct.
When running, IC1 readings are all 0V except for 7 = 5.23V, 9 = 3.3V, 16 = 5V so appears correct.
IC2, all readings are 0V except for 1 - 2.38V, 4 = -5.23V, 7 = -1.65V, 8 = 5V so all correct apart from “1”.
When I connect the EDU06 kit, nothing happens on the laptop oscilloscope scree (EDU06 LED 1 lights and LED 2 and 3 flicker at the same time, not alternatively.
I pressed the Autoset button and the screen locks with a “Autoset please wait…” message.
Your help is appreciated.
If not done, please try recalibration:
Select Options → Calibrate
If fails, then open the Calibration.log in a text editor and copy the content to the post.
1 Like
Calibration results as requested:-
CH1 offset at 2V/div : 77 FAIL
Rounds : 51
CH1 offset at 1V/div : -46 OK
Rounds : 51
CH1 Y-position low, CH1_DAC1 255 0
Rounds : 33
CH1 Y-position mid, CH1_DAC0 255 77
Rounds : 51
CH1 Y-position high, CH1_DAC2 255 173
Rounds : 51
These are typical values when the voltage on pin 1 of IC2 is “out of range”.
Several similar cases discussed in this forum.
In most of the cases cause was bad soldering.
What is now after calibration the voltage on pin 1 of IC2?
Both when software not running and when running.
1.71 when not running, 2.38 when running.
Please do the following test:
- Select: File → Restore Default Settings & Exit
- Start the software.
- Do not calibrate - Click “Cancel”.
Now check the voltage on pin 1 of IC2 (software running).
Pin 1, IC2 reads 1.71 when running (stopped is the same).
There is no change to the screen readings when connected as Experiment 1, EDU06 but pin 1 IC2 drops to 1.54.
Does the trace’s vertical position change when connected to EDU06?
Is there any difference if you use AC or DC coupling?
I don’t think so but the screen has frozen again stating - “Autoset - please wait”.
It seems there is some problem in the input section of the scope if no change is noticed.
There should be a quite high AC signal seen on the screen in Experiment 1.
This is very strange…
Please check the continuity of the test leads.
If possible, please post a picture of the solder side and the component side of the board.
I checked the lead continuity and position of components previously as well as the soldering but would appreciate your comments.
The solder does not penetrate and fill through some of the holes to the top but underneath the soldering looks good.
I did have to remove the C4 capacitor from position C3 after mistakenly soldering in the wrong place - could the de-soldering have damaged the capacitor? I have tried to check C4 with a simple multimeter (does not have the capacitance facility) and it appears to be ok.
I hope the photo’s are clear enough.
Thanks again
It seems that pins 2 and 3 of IC3 are not soldered.
Are these two pins broken or bent or totally missing from the socket?
Pin 2 is needed. It is the analog input of the microcontroller IC3.
Pin 3 is not in use.
The IC3 socket has 2 and 3 missing, that’s is how it was when taken from the pack.
I’m sorry that a defective socket has been put to your kit.
The assembly and the soldering looks very good.
I think the missing connection from the bottom side of the board to pin 2 can be the only problem.
Yes, very disappointing.
It is the second kit from Whadda that has not been correct, I am wondering whether to buy anymore.