K8115 Kit Component tester does not work

I have soldered the kit according to the manual. Checked every connection. All seems to be ok. But the display does not do anything, no backlight, nothing.
Would be very grateful for some help with this.

Hello pieter2,

First can you upload a picture of component side of PCB and soldering side.

Then, check the polarized components ! D1, C7 & 8, T1 = BC557, T2 & T3 = BC547, Check polarisation of U1 and IC1, VR1 = LM385Z2.5, VR2 = LM78L05, VR3 = KY5033.

Use a new full battery

The most common reason that there is no text on the display, only backlight is active, is a defective chip IC1 => CD4050.

We had a bad CD4050 delivery during a production batch.

To get it working replace IC1 CD4050.

If desired, We can send a CD4050 to You by post.
Create (open) a new ticket for this on our customer care service platform: Customer Care Velleman.

At this way, We can help You faster to solve this problem.

Best regards,
Velleman Support

Thanks for the support! I have checked all polarized components. All seems to be ok.

Different form other posters with this problem, my LCD does not give any backlight. In the beginning I saw sometimes just a black flash, but now it does not do anything at all.
I have checked the voltage at the pin header. I find 3,3 V when I press the reset button.
I have asked my supllier for a new CD4050, but I wonder if that is going to help. What else can I check

PS: I used a full new battery


It seems to be a problem with LCD. In this case, I think it’s better to bring the module back to your local shop for RMA request. So the local shop send it then to us for repair.

Best Regards,
Velleman Support

Thank you for the reply. I have send the total kit and will be awaiting your answer.
Kind regards,

Today I recieved the component tester after your repair of the lcd. Everything works very well. Thanks a million for the great service!
Kind regards

Hello pieter2,

It’s nice to hear that it’s now working correctly.
Have fun with this tester.

Best regards,
Velleman Support