I am trying to repair an Ecolite.I found that it has a MMBTA42 as oscillator for wireless.The grounding resistor is open.How do I find the value to replace it?No info available on circuit. It is a 276 V system.When I arbitrarily substituted a 10K resistor it worked . But how do I know that is the correct value? Please help.Thanks.

 

Unless you have a circuit schematic it would be difficult to know what the correct value is.

 

Thanks.There is no info available on the schematic.All components are SMT. Color coding or values are not written on resistors.ID of transistors,diodes and capacitors are available. This is almost like reverse engineering.

 

Here is the circuit.I am trying to find the value of R3.