CTB16PC

[guyfox_318c]

Well, I bought 3 CTB16PC's and assembled the first 2 with only one mistake.

Anyhow, I thought my third would be quick and painless, of course not.

After assembling it, I tried to power it on, nothing. I checked all the resisters as well as the orientation of every piece on the board. It was perfect. I even resoldered every joint on the board to make sure.

I decided to test the 2 chips next. I got out one of my working CTB16PC's and swapped out the chips, one at a time. The micro processor was fine, but when I tested the RS485 "isl81487lip" it did not work in my good board. When I put a working chip into the bad board, still nothing.

However, when I put the working chip back into the working board, nothing. Somehow the RS485 got fryed in the bad board.

What would cause the RS485 to fry? I have looked for shorts and have found none and checked the resistors a third time.

Also, all the chips that had multiplies seemed to have different fonts on them, like they were from different manufacturers. Would this have played a role.

Any Idea's?

Also, incase you read this Dan, I'll be needing at least 2 new RS485's, but I'll contact light-o-rama monday or tuesday.

Thanks

[Denny]

Guy,

Did you check the value of R17 to make sure you installed the correct resistor? There is a Warning there that installation of the wrong resistor will fry the micro-processor. The correct resistor is 470K ohms, yellow-violet-yellow. See page 13 of the instructions.

[guyfox_318c]

R17 is correct. As I said, I have already triple checked all resistors.