Problem resolved!
This is an update to a question I posted several months ago. I am sending this to the group for the benefit of all in case you shoulld run into the same problem I had.
My problem:
I have a BLI Paragon HO Atsf 2-10-2. It has a QSI decoder with version 6 firmware. I had the loco a number of years, but had never run it. I have recently gotten where I am making time for my trains so I went to program and run this loco. It ran and sounded fine in the forward direction. When in reverse, the chuffs would start way out of sync with the wheels. It would then settle out while running in reverse, but upon stopping, the chuff sound would continue forever until I changed the direction on the throttle, then it would stop.
I found this annoying and unacceptable. I asked on this forum about it and Kelly offered to have a look. I waited around a few months and reached out to Kelly again and asked about the possibility of a chip upgrade and thinking that might solve my problem.
Kelly was able to secure a new chip with version 7.x something firmware and sent it to me.
I put it in a few weeks ago, and much to my disappointment, the problem was still there. I figured I would wait til I had some time to try to troubleshoot it or get into the bowels of the new software which I know nothing about.
I tried various settings and still no joy.
I decided to take out that decoder and put in some other brand I am more familiar with. I installed that decoder yesterday. I started blowing LED headlights. This is not my first rodeo and I knew I had wired it right and I had put in a 1kohm resistor. So I changed the headlight again, and this time hooked a battery to the headlight leads before attaching the harness up and the headlight worked fine. I hooked up the harness and put it on the track and blew the headlight. Now by this time I was pretty darn frustrated. Changing the headlight on this loco is no small affair.
I decided to pull out my multimeter and checked for continuity on all the pins of my wiring harness. Lo and behold, I had a short from the headlight white lead to the motor leads. I then disassembled the locomotive to get at all the interior wiring. The jumper board where the harness coonnects from the tender metered the same short with the headlight wires disconnected and the tender harness disconnected. So I took my exacto knife and cut through the pc board surface between the solder pads for the white headlight wire and the gray motor wire. I did this on both sides of the board. Still registered a short. I cut between the wire traces on the 6 wire pin header attached to the board. Still had a short. Cut between same traces on back side of 6 wire header. Still had a short. I finally worked the tip of my knife in the tiny slit between the 6 pin header and the surface of the pc board and just sliced between the 2 offending pins. Finally the short was gone.
I changed the bulb a 3rd time (4th bulb) and metered everything again. I then tested with a battery. Then I reassembled the loco and hooked everything up and it all worked as expected.
Now remember, I had changed out the decoder to another brand. By this time it was 1 an this morning. I decided I wanted to try the QSI decoder again. But it had to wait.
So, just about an hour ago, I started reinstalling the QSI decoder. Fortunately, I did not destroy the connections by cutting the wires too short when I switched to the other brand. I was able to solder up a harness to match all my quick connects I use whenever I do an install.
I put everything together and put it on the track.
I am happy to say it all works, the chuff stuck on problem is gone. I am very happy with this decoder and its sound and features.
I dont know if the bulb was already blown from the short before I switched decoders or if the QSI decoder absorbed the load into its circuitry and still kept the bulb lit. I think the headlight was working because that is always one of the first things I deal with programming.
But I am making a new practice of checking for shorts with my meter before I mess with anything.
Now, to spend some time getting to know this QSI software and what I can do with it.
Thank you Kelly for all your help!