I recently bought two AC4400 CW’s from Athearn and after an exhausting period of time programing I have them matched in speed when moving forward but when moving in reverse they are not the least bit close in speeds. Is there any CV adjustment for this difference or is this just the quality expected from this make of loco’s? Aside from the noise etc.
As long as I don’t reverse travel for a long period of time I should be OK! To add to the frustration I have added a third AC4400 but this one is KATO’s and KATO’s operations are far above Athearn in every respect, poor Athearn.
Upon further investigation I have since found that after the loco’s have been matched in forward using a combination of CV’s 2 (start voltage), 5 (Voltage Max), 6 (Voltage Mid Range), that SOME decoders use CV 66 (forward trim) and CV 95 (reverse trim) for further and closer speed matching in both forward and reverse.
So if your decoders handle these CV’s, no need in spending money on motors that don’t match. That’s what the decoders are designed to compensate for.
The trick is to observe your loco in forward then reverse. Use the SLOWER direction to speed match to your ‘golden’ locomotive. Then use the trim to adjust the opposite direction.
So…the steps for speed matching are…
FWD vs REV (choose the slower direction first)
CV2 (set until loco creeps at speed step 1…some Athearns have values upwards of 50)
CV5 (set until loco top end matches other loco)
CV6 (set at 1/2 of CV5)
Set Trim until both directions have the same speed
Dave, after speed matching the loco’s everything was running great for about 3 to 4 hours of useage(not all at once) one of the other loco’s , not the golden one, slowed right down like it never got matched. I checked for dirty wheels and track and checked all the CV settings for same settings that I tracked when I first set them up. All CV’s OK! but now I have to re-speed match. Whats happening or is the expected result from Athearn products. Decoders not over heating either.