Hello good people, hope you are all well.
I have the 1602A LCD, I tried connecting it to the Arduino following these steps:
However, I didn't use a 10kpot. LCD powers on but remains blank. What could be the problem?
Thank you
Why did you not use a 10k pot? Why would you expect it to work without a critical component?
Clearly it is necessary, or in fact, not really necessary. 
You can try connecting pin 3 to ground, but it will probably work better if you connect it to ground through a 330 or 470 ohm resistor. If that works, you can try other values to get the best contrast.
The commonly published circuits using a 10k potentiometer are actually wrong - you only need a 1k pot connected as a variable resistor between pin 3 and ground and once the value is adjusted, it never needs changing unless the supply voltage changes.
The commonly published circuits using a 10k potentiometer are actually wrong . . .
No they aren't, even when boldfaced. They illustrate a technique that works quite well and has done so for decades.
Just because you have come up with another technique that seems to work doesn't make the data sheets wrong.
Saying that the published circuits are wrong implies that the display will not work if those circuits are used which is clearly not the case.
Don
Just pointing out that it was a design regrettably carried over from a proof-of-concept lash-up in some later app note.
I have not "come up with another technique that seems to work" at all. I reviewed the HD44780 datasheet yesterday(?) while I was checking on the current draw - it shows a variable resistor as the contrast adjustment.
The use of a potentiometer has been blindly copied ever since. It makes no sense at all - the current drawn by the 5 V leg of the potentiometer serves absolutely no useful purpose. It may be only 500 µA, but that is a completely useless 500 µA being drawn from your battery if a battery is used or indeed any other power supply. Cutting the trace from the 5 V leg of the potentiometer is a very sensible modification.
I think Mike not infrequently distinguishes between "working" and "correct". This problem is not harmful in itself - unless you are operating from a battery - but it is a mistake.
Connecting pin3 of the LCD to ground worked even without a resistor or a 10k pot so thank you so much this really saved me a lot of time so thanks again
Yes, but you might later try the resistors - 220, 330 or 470 Ohm to see if you get better contrast.