MR-02 PCB help needed

SuperFly · Post by **SuperFly** » Mon Oct 10, 2005 2:10 am

My MR-02 PCB is fucked, but I think salvagable. As you can see in the red rectangle, my pad is destroyed/gone as well as a little of the trace coming away from it.

I have a whoa nelly waiting to install, or I could put some new fets back in. Is there a place in the C12 area I could tap into instead of that pad? Any advice welcome.

Zenith · Post by **Zenith** » Mon Oct 10, 2005 10:26 am

I dont know any thing about the MR02 PCB, but it apears that the pad's trace leads up to the second trace above it.

SuperFly · Post by **SuperFly** » Mon Oct 10, 2005 10:33 am

hehe, that's just some solder sloppiness. The trace keeps on running under the black box and out the other side, but I'm not sure which of the traces coming out from under the black box on the left side it is.

My thought is that I could solder on to where it goes through the PCB (those little circles) to the other side of the board.

Zenith · Post by **Zenith** » Mon Oct 10, 2005 11:00 am

Well what about cutting/scratching some of the solder mask so you can run a jumper?

sg219 · Post by **sg219** » Mon Oct 10, 2005 12:11 pm

Not much of a geek, but I think soldering to the other side might be your best bet.

Don't they sell something at RS that makes or replaces the tracing?

SuperFly · Post by **SuperFly** » Mon Oct 10, 2005 12:22 pm

sg219 wrote:Not much of a geek, but I think soldering to the other side might be your best bet.

Don't they sell something at RS that makes or replaces the tracing?

I agree about soldering to the other side. There just has to be a spot that's nice and sturdy somewhere else on that PCB. I've seen people fix MR-01 boards that way, by going over near the C12 area, but the MR-02 board is different enough that I need someone smarter than me to tell me where that is.

Yeah, they do make a pen that will draw conductive ink, so to speak. The problem is that whatever route I go, I need to be able to solder to it. That would work if I just had a break in the trace, but I need to stick either a fet or a Nelly wire to it.

richh · Post by **richh** » Mon Oct 10, 2005 7:10 pm

it looks like some of the solder mask is already gone to the right of where the pad used to be. i would just solder some fine gauge hook up wire there, running the other end of the wire to the left. then solder fet back down (7 of the 8 legs that is), and then bend the wire back over and solder it to the last leg. then add a little hot melt or epoxy on the wire and it should hold.

depending on the wire you end up using, you might have to bend the legs down a little to clear the wire.

LBRC · Post by **LBRC** » Mon Oct 10, 2005 11:38 pm

Option one, use a multimeter to find the correct “via” that’s the hole where it runs though to the other side of the circuit board and connect the jumper there. Better than trying to run a jumper under the FET or even off a run.

Option two, good time for a Whoa Nelly, then you could solder the hookup wire directly to the run, securing it with non corrosive RTV, or from the via.

SuperFly · Post by **SuperFly** » Wed Oct 26, 2005 1:07 am

LBRC wrote:Option one, use a multimeter to find the correct “via” that’s the hole where it runs though to the other side of the circuit board and connect the jumper there. Better than trying to run a jumper under the FET or even off a run.

Option two, good time for a Whoa Nelly, then you could solder the hookup wire directly to the run, securing it with non corrosive RTV, or from the via.

That's what I'm going to do. I multimeter tested the vias, and these two beeped. I just need to run a little jumper from one of the circled vias (it goes to the other side out the lower one and back in through the upper one). What is RTV? It sounds really useful.

Zenith · Post by **Zenith** » Wed Oct 26, 2005 12:40 pm

RTV-Room Tempurature Vulcanizing. It's like weatherstrip adhesive or silicone.

LBRC · Post by **LBRC** » Wed Nov 02, 2005 10:58 pm

Not as useful as duct tape but a close second.

sat4life27 · Post by **sat4life27** » Thu Nov 03, 2005 12:46 pm

I had the same thing happen in the same spot with a mr01 board. I just used a small piece of wire and scratched off a little piece of the coating on the board right next to where it broke. Soldered it to it and then soldered the fet to the small piece of wire. After that I used a little bit of hot glue to cover it and protect the wire. I did that to the pcb I am using in the Import racer.

SuperFly · Post by **SuperFly** » Thu Nov 03, 2005 1:10 pm

After the "eureka" moment of realizing all those little holes (vias) are just like sockets to poke jumper wires into, I had my pcb back up and running in no time. As long as you have some shred of original trace to touch a multi-meter with a circuit-checker to, you can just test all those vias till you find the right one. After I got back into mine, I realized I actually had 2 destroyed pads, not just the one. 2 jumpers later and I have a nellified MR02 pcb.

KuZGuN · Post by **KuZGuN** » Tue Nov 22, 2005 8:16 am

Superfly if you give me your e-mail i send to you a pad photo by sended me to ph2t. It's works.