Genesis SD70 light board

[LotoQuestions]

Genesis SD70 light board

Well I am back at the light board replacement Digitrak decoder install that gave problems with the lights (dim originally and burnout with the jumper cut).

Going back to square one - TEST working light board (out of unit) using digital multimeter and powerpack to verify original voltage.
Supply 15 volts (meter verifies) to outboard pins on one end of board.
Test - expecting 1.5Volts or 0.0 depending on direction switch of powerpack on 2 center pins of either end.

Result - varies around 0.20 to 0.32 on both ends with no difference in polalrity or supplied voltage.

Obviously something wrong about my assumptions or my technique ??????????????

thanks ,,, ken

p.s. The voltage on the lightboard motor pins measures correctly at the input level. This lightboard was working before removal for decoder install.

 

[bnsf971]

Ken, make sure the Digitrax decoder has the CV for the lower voltage enabled. I had this problem with an SD75, called Digitrax, and they walked me through some CV checking and changes.
Now, that was a few years ago, and the new decoders may do this fully automatically now, but it won't hurt to check.

 

[LotoQuestions]

Voltage values etc.

Ken, make sure the Digitrax decoder has the CV for the lower voltage enabled. I had this problem with an SD75, called Digitrax, and they walked me through some CV checking and changes.
Now, that was a few years ago, and the new decoders may do this fully automatically now, but it won't hurt to check.

Terry, thanks but all I can find is a trace link on the board that is documented to increase current from 15 to 30ma. That was what finished the bulbs on the first try with the decoder(DH165ao) on the recommendation of the LHS.

This time I am going back to square one and trying to demonstrate to myself the matching of actual measured voltage/current values to those expected all using the original lightboard and then I will return to the decoder when I know I can check it.

thanks ,,, ken