hello,
i’m trying to get life to this generator. It was built by my friend but never working.
here’s what I’ve checked:
all components are on the right places
voltages on regulators are OK (+5V,-5V,+12V,-12V)
communication with PC works fine,LD2 lights when I click waveform button
power consumption is about 0.6A
what should I do next for chcecking?
thank you.
If you have an oscilloscope you can check the signal path.
First check the signal on pin 6 of IC33.
If no signal then check the digital-to-analog converter IC6 outputs.
If still no signal then check the IC6 data and clock inputs.
If there is waveform found on pin 6 of IC33 then follow the signal path to the output via IC14, R50, IC13, RY1 to try to find the problem.
thank for answer!
there is no waveform on pin 6 of IC33, only -1.4V
outputs also no waveform, pin 14 of IC6 is 3.3V, pin 15 of IC6 is 4.8V
pins D0-D7 are 4.3V
Do you see any data on the address pins A0…A14 of IC10 when the generator is set to output some signal?
Also check if there is any data on these pins when you change the signal frequency or the amplitude setting and the waveform button is pressed “down”.
also no data pulses on IC10 
Please check that there is 320Hz frequency clock pulses on pin 9 of IC22.
This indicates that the oscillator X1 and the counter chain IC8, IC4, IC11 is working correctly.
yes, there is the correct frequency
Is the frequency on pin 20 of IC22 320Hz when the frequency range 0.1Hz is selected on the user interface and the sine button is pressed down?
no,there is no frequency
The problem may be in the shift register section IC2, IC3, IC19, IC21 or in the optocoupler IC37 circuit.
Next you can check the IC2 outputs DC0…DC7.
Is there any state change if you change the Offset slider when the sine button is pressed down?
Please check the voltage on pin 8 of IC37. Should be about +5V.
no changes when I’m changing offset slider.
Pin 8 of IC37 is 4.62V. I’ve also checked pins 8 of other optocouplers and there is 5.00V
It seems that either DATA, CLK1 or RCK1 to IC2 is missing.
You should see about 1 second burst of fast pulses to CLK1 and to DATA inputs when the frequency slider is changed and the sine button is kept pressed down.
To the RCK1 input there are sent two pulses from IC22. Pulse length about 10us.
I am getting those fast pulses now to pin 14 of IC2 when I’m pressing sine button or hz button. But no pulses pin 11 of IC2. Also no state change on D0-D7 on IC2.
LD2 diode dont work now.
Do you see any pulses on pin 1 of IC22 when you click the sine button down?
Please see this thread: viewtopic.php?f=11&t=4277
There are screenshots of the waveforms measured on pin 1, 2 and 3 of IC22.
The single shot mode is used in the oscilloscope.
yes, pin 1 of IC22 is OK, pin 2 no waveform, also pin 3 no waveform
IC19 states when sine button is down are
pin
15 = ‘1’
1 = ‘0’
2 = ‘0’
3 = ‘1’
4 = ‘1’
5 = ‘1’
6 = ‘1’
7 = ‘1’
IC21 states are
pin
15 = ‘1’
1 = ‘1’
2 = ‘0’
3 = ‘0’
4 = ‘1’
5 = ‘1’
6 = ‘1’
7 = ‘1’
Please check IC35 and IC36.
Is there also no output on pin 6 of IC35 and IC36.
Are both of the pins 2 and 3 of IC22 at +5V all the time?
IC 35 and IC 36 pins 6 are both +5v without any changes. Also pins 2 and 3 of IC22 are all the time +5V.
i’ve edited my previous post with additional info about IC19 and IC21 states.
[quote]i’ve edited my previous post with additional info about IC19 and IC21 states.[/quote]Yes, I see.
For some reason IC21 data seems to be OK.
The main problem is that the IC22 is not getting the pulses to pins 2 and 3.
The problem is somewhere around IC35 and IC36.
Please check the resistors R74 and R75 are 100 ohm.
yes resistors are 100ohm both
Now you have to check the input side of the optocouplers IC35 and IC36.
Connect the oscilloscope ground to the mounting bracket of the 25 pin cable connector.
Check the pulses on pin 3 of IC35 and IC36.
The pulse amplitude should be about 3V.
Also check the voltage over C11. Should be about 3V or more.