Paul, First off I would say keep working at it. You are really close and I am sure it will be one or two connections that separated. This group will help you persevere. Secondly, do a little web search or even check out RobRob's page on lead dress and shortening those circuit wires as much as possible to reduce hum. And Thirdly, it appears that some of your twisted wires have come apart a little (I am sure with the probing and poking), twist those as tight as you possibly can as close as you can to the connection points to reduce hum.