RAT Footswitch replacement gone wrong - can anyone help?

Following my previous post, I've removed the old switch in my sickly RAT and put in the replacement one, soldering the wires to the equivalent terminals on the new switch. When I put a battery in and insert a lead into the input, pressing the footswitch activates the LED but when I plug the output into the amp, I get no signal through the pedal either on or off. This is my first time "having a go" and would be grateful for any pointers as to what to check.
Anyone know which terminal does what and if I were to use a multi meter how could I work out the problem?

The pedal was fine (apart from the increasingly intermittent footswitch) before I attempted to repair it. Here are the pics of the old switch in situ together with the replacement which Proco sent.

The X wing switches are a little confusing. To compound matters, the terminals look a little different on some of them - see my attached pic as a reference.

But the basic jist is that the two terminals that are not part of the "x axes" are the ones that get routed to the input and output jacks (via the red wires in my pic).

Out of the remaining terminals, two simply get jumpered so that the signal is simply passed in bypass mode (the stubby red wire in my pic). And the other two constitute the input and output connections to the circuitboard. Obviously, the input must coincide with the connection to the input jack, and likewise for the output jack. It's usually easiest to trace the pcb to determine which is which.

...This assumes that your particular Rat uses the "electronic switching" method that was conceived by ProCo to activate the LED and still have true bypass. If it's a RI that is actually using one of the poles to switch the LED on and off, then the standard wiring of the X wing switch will not work.

You're going to have to trace some of the circuitboard leads and see where they terminate. The in and out to the jacks will make for a quick determination. If they connect as I explained above, you can simply match the wiring in my pic.

Do you have a picture of how you have it wired now? Basically, you need to wire it just the same as the old one. Yes, the terminals look different, but it's still the same 2x3 arrangement of terminals and they have the same functions on both switches.

Also, it looks like the clearance is tight where you'd have the terminal of the new switch coming out right next to the wall of the chassis. Make sure that connection isn't shorting to the chassis.

OK, here is a pic of the new switch wired up. Nothing appears to be touching the chassis. Everything seems to be wired up to the same terminals as the previous switch but I'd be grateful for any help in identifying the problem...I think the black and white insulated wires go to the input/output jacks but beyond that I haven't a clue. I've soldered new pickups into a tele before with no probs but this is my first go at a pedal and a switch so I haven't a clue.
Can I make use of a multi-meter to help find the fault? If so, how?

Well, I'm having a tough time telling what's going where without a schematic. I haven't worked on a Rat before, so I'm not familiar with how it's laid out on the PCB there.

Assuming that it's all hooked up the same, I would check two things. First, the solder joints on your switch terminals don't look very good. You don't need to fill the terminal with solder, but you need to get more solder on there. Be sure to get the terminal hot enough so the solder wets to it well. Second, I would check those bare wires running down to the PCB. It looks like it would have been easy to have gotten them hot enough to reflow the solder on the underside of the PCB, possibly causing the wire to come free at that end.

I think the black and white insulated wires go to the input/output jacks but beyond that I haven't a clue.

Can I make use of a multi-meter to help find the fault? If so, how?

If the black and white are the input and output, then there's a problem. You have them both connected on one of the two poles as it's currently wired. So on one throw you have the input and output connecting, but on the other, you have one of the two connected to something else, and one not connected at all.

You can use a multi to help determine some of the connections. Since you should be able to get to the "tip" terminals on the jacks, when the switch is correctly in bypass, connecting both probes to the "tips" should yield either ~0 ohms if checking for resistance, or a dead short when checking diodes. If you get an open circuit (with the pedal set for bypass!) across the tips, then something is wired wrong.

The absolute best method is to have a schematic, and trace each connection from the switch to whatever component it terminates to. In the case of the Rat, the connections on the circuitboard should terminate to some of the following:

- INPUT: the input cap (.022uF) and 1 meg "pulldown" resistor to ground are the first things on the pcb that the input trace will make contact with

- OUTPUT: The middle lug of the Volume pot will be the last thing on the pcb that the output trace will make contact with

Armed with the above information, you can determine both the IN and OUT of the pcb, as well as the IN and OUT of the jacks. This is half (actually 2/3) of the battle.

...Supposing that we don't know which terminals of the replacement switch do what, you can use the multi to test that as well. In a nutshell, when you get ~0 ohms or a dead short, you have two terminals that are switched to be connected. Then the task is to pair the terminals that will send the signal thru the pcb, and pair the terminals that bypass it around the switch itself.

I would save the LED switching for last. Just because it lights up doesn't indicate that it's wired right.

Tracing the circuit will be both a great learning experience and a definitive method for determining which connection actually goes to what. Aside from having the proper info about the pedal, the switch, and a schematic/layout and data sheet for each, that's the only way that I can recommend doing it.