Programming BLI Switchers with PowerPax

Buy Broadway Ltd Locos Here | More About Switchers
Reversing Issue / Fix

We have received reports of difficulty programming the Broadway Limited Switcher, particularly with NCE and Lenz systems. This issue may also be applicable to the Proto 2000 GP9. Both use the QSI Sound decoders.

We used a PowerPax with Digitrax, NCE, and LENZ systems on the program track (service mode). We found that the Digitrax system did not seem to have any problems reading or writing CV values on the BLI Switcher. The NCE system was unable to read CV values, but was able to program them correctly. The Lenz system was unable to read or write CV values, and actually managed to scramble the address and direction values.

As near as we can determine, the issue may be timing problem with the BLI decoder. Fortunately, there is a very easy fix. We found that a 12 ohm 1 watt resistor (Digikey P12W-1BK-ND or equivalent) placed between the PowerPax and the programming track in series with one of the PowerPax output leads solves the problem. With the resistor installed, all three systems were able to read and write CV values correctly. This could be made as a permanent change to your programming track setup since it does not appear to affect the programming performance of other decoders.

We welcome comments or suggestions from readers; please write or call.