The most possible reason why the amount isn't showing on the cheque is because of the alignment. Let's try to set it up to make sure the numbers will align with the amount box.
These are the steps to follow:
Go to the Expenses tab and select Print Cheques.
At the bottom of the page, select the Print setup.
Select the type of cheque.
Print a sample using a blank paper. Select View preview and print sample, then choose the Print icon.
Once done, place the sample on top of a blank cheque page to see if it's aligned. If not, click on the No, continue setup button. On the Fine-tune alignment page, adjust the grid inside the amount box. Then, print another sample to see if it's good already.