Sounds like you have a blown connection at the comm tab. If you look at the three connections you'll see the high-temp solder missing off one of them. You can resolder it if you were able to get some of that high-temp stuff.
You can spot welded with 1200 degree Silfos, a special material plumbers use for brazing copper together. It never comes off. But Mike Reedy believes this temp is too hot as it tends to anneal the copper plates making them wear faster, he says.
This a quote from "Big Jim" when I had the same problem with my Reedy TI 9x2.
Pro 10 / 10th scale pan GTP: Speed Merchant Road Kill 10 (one of the first 10 produced)
12th Scale: Speed Merchant Rev 8 PRO x2 and Yokomo YRX12
"Pro 10, the only way to fly around the track!"