MK157 LCD messageboard

i’ve assembled the board as instructed, and when i put the batteries in the screen automatically begins to scroll the velleman message. most buttons aren’t working but ENTER seems to be able to freeze the screen and sometimes fills the screen with U’s. i’ve looked at my soldering there doesn’t seem to be any problems but there obviously is, can anyone tell me where they think the problem lies so i can focus on that part? i don’t think i’m going to be able to unassemble it all.

please help it’s driving me crazy. !!! a load of jargon now appears when i press buttons.

It sounds like you might have a solder bridge between two chip leads. Either that, or perhaps a backwards chip. If you are getting a bunch of jumbled text there is more then likely something wrong with one of your chips. (at least thats what I’ve encountered from previous experiances)

If you have a multi meter that can check continuity, check point to point from components to chips, and even from the bottoms of your chips to the top legs.

Even tho solder can conduct, it is not a very good conductor. I have had an open from solder point to pin before, this happens when you don’t get the chip pin hot enough to accept the solder.

Just a few things to think about.

If you could post a picture, I could attempt to help you more, or you could wait for one of the Velleman guys =D

PIC and LCD seem OK, as default message appears.
Use multimeter to check continuity between buttons and PIC inputs.
Watch for solder bridges, bad solderings, forgotten solderings, damaged tracks and pads, etc…