I put a "Digitrax" SDH104K1A SOUNDFX Decoder in my HO Scale Kato GE C44-9W. Not super impressed but works ok...except that after setting all the CV's just right, the way I wanted, I noticed that the engine "behaves" differently in reverse than in regualar forward direction, particularly when I try to fine tune CV2 starting voltage. Could this be a bad decoder, or is there a particular CV that will 'match" forward settings and "behavior" with reverse settings and "behavior". This is important because I often MU this engine in the reverse facing direction and it causes problems.
I think you are going to have to define "behaves differently" if anyone is to help you. for example, runs too slow, jerks, heaves, spits up whatever this bad behavior is. I have many Kato HO SD40-2 mid range diesels, and I use the same decoder brand and model in all of them, and still see some with a little bit of difference in how they run.
What does yours do running backwards?
Bob
Thank you for response. the main difference is the starting voltage CV2. In forward the engine starts moving nice and slow at throttle on 1 or 2, but in reverse I have to get up to 15 or 20 before the engine even starts moving.
9 times out of 10, this is a mechanical issue in the locomotive, not a decoder issue.
Probable cause #1: too much axial play in the worm shaft (the shaft with the spiral gear). The gear rides forward or backwards, depending on shaft rotation, and increases friction due to improper gear mesh. If there is more play in one direction than the other, you will get the results you describe. Another sympton is "bucking" when going down a steep grade with a train pushing it downhill. The most common fix is to add thrust washers to take up the extra space and limit the axial "play".
Probable cause #2: gearbox rotates slightly with change of direction. This sets up problems with gear and/or motor alignment. Often, torque arms are used to stabilize a gear box, or to lock motor and gearbox together on steamers.
hope this helps
Fred W
Thank you for the suggestions. I may have to take this Kato engine apart and see what is happening. I must say all my engines by "Atlas" have been virtually trouble-free. Its only the other manufacturers (BLI, Athearn Genesis, Kato, etc.) that seem to have performance "issues" even brand new out of the box. Oh well, good QC at Atlas I guess.
I have 15 Katos and have never had any more (or less) trouble with them than the Atlas Chinese Kato clones (which for both is pretty much nil). Did you try running it on straight DC to see if the problem is there without the decoder? Check the lube in the trucks.
Jay
C-415 Build: https://imageshack.com/a/tShC/1
Other builds: https://imageshack.com/my/albums
Always a good idea to do a good break in run when you first get the engine, 15 min or so forward, then 15 in reverse. Often works out a lot of kinks.
If you set the CVs to allow for speed curves, it could be that you need to check CV 66 and 95. They allow you to change the forward and reverse speed overall...essentially they're used to move a speed curve up or down a little (or a lot) without having to redo each individual CV in the speed curve. If 66 is higher than 95, the engine will go faster forward than in reverse, vice versa if 95 is higher.
Thanks to all. I'll do that 15 min warm up. And yes, most manufacturers are doing a great job compared to how things "used to be" as far as engines performance and detail.