PC Oscilloscope Kit WSEDU09 calibration failed notice

Just finished making the kit and when connected to my laptop the red LED illuminated as required.

Ran the software and the calibration but after appearing to reach 100% I received a screen message stating the calibration had failed.

Anyone know why this would happen?

There have been several similar cases discussed in this forum.
In most cases the problem has been bad soldering or solder bridge on the board.
The calibration results may indicate that the charge pump is not working.
If this is the case, there is no -5V on the board.
As a first test check the voltage on pin 4 of IC2.
There should be about -5.2V.

If not, check all the voltages of the charge pump.
In this thread there are instructions and voltage values:

If -5V is OK, then check the voltages on all pins of IC1 and IC2.
In this thread there are the voltage values:

Also check IC2 orientation.

In the following threads there are some examples of about similar problems and solutions:

Read the other articles and carried out the checks with the following results:-

My readings are as follows:
A, B, C correct, D 2.94 not 3.09, E and F correct.

IC!, 1 to 6 0V, 7-5.24V, 8 0V, 9 0V should be 3.3V, 10 to 15 0V, 16 5.02V.

IC2 1 is 0.23V, 2 is 0.23V, 3 is 0V, 4 is -2.23, 5 is 0V, 6 is 1.79V, 7 is 1.05, 8 is 5.02. .

Help please!

The charge pump seems to work OK.
On pin 7 of IC1 there seems to be correct voltage -5.24V.
On pin 4 of IC2 there should be same voltage as on pin 7 of IC1.
Unplug the USB cable and check the continuity between pin 4 of IC2 and pin 7 of IC1.
There should be 0 ohms between them.

Pin 7 of IC1 and pin 4 of IC2 both have -5.2.

And yes, continuity between the above pins is 0V.

Are other voltages on IC2 pins still same as before?