Broken RS 15-100

[srwalter]

While attempting to add a JP1 header to this 15-100, I accidentally removed R21. Worse, I pulled up one of the pads under the resistor. The remote actually seems to work flawlessly, except that no IR transmission actually occurs. The device doesn't respond, and the red LED in my IR receiver (which blinks whenever I use any remote) doesn't light up.

Obviously I need to reconnect the circuit that I opened by removing that resistor. However, there's nothing to solder to where the pad was, and there is no visible trace to follow to figure out where the connection goes...

Ideas?

[The Robman]

However, there's nothing to solder to where the pad was, and there is no visible trace to follow to figure out where the connection goes...

How come? The pad would have had to be connected to something. If someone has a working 15-100 and is willing to open it up, they could find where R21 connected to. Once you have the info you'll have to run wires to restore it.

[3FG]

Unless the board is surface mount, a resistor is mounted by the leads which each go through a hole in the board. A connection to the resistor can be made either on the component side of the board or on the reverse side. Have you looked for a trace on both sides?

[srwalter]

Thanks for the reply! Unfortunately it is a surface mount board. Additionally, the other side is the Lcd didplay.

[Tommy Tyler]

Here's what the area around R21 looks like. The left end of R21 connects to the right-angle trace and the right end connects to the left end of C27 below.

[srwalter]

Here's what the area around R21 looks like. The left end of R21 connects to the right-angle trace and the right end connects to the left end of C27 below.

Aha! Sure enough I'm lacking continuity between R21 and C27. Does that circuit relate to IR transmission? Seems odd that the TX pin of the processor would be involved

WOOHOOO FIXED!!