Hi Ed ,
Thanks for your input on this issue. I am familiar with the linkage you are referrring to, but I got fed up with it, so before I went into destructo mode I figured I would let BLI take a look since it is under warranty. It makes sense what you have described, that is how it was responding. One minute it was moving fine , all of a sudden it seemed like it found a bad spot in the links and started jerking. I hope they see the samething. It will take appoximately 11 weeks for them to look at it! No big deal since I am still in build mode on my layout.
BLI responded right away and offered several ways to handle this, either they would work with me while I did some investigations on it or send it in. The new decoder was sent out , but was not the issue. I hope they will resolve it, I do like that model and the fact that it is Southern Pacific! Marty
Marty www.pbase.com/Hejhog
you tube/martyHejhog1
Hi, Marty,
I have an older pair of BLI RSD-15s and I just had to replace the drive shaft "dog bones" since the hex end that slips into the flywheel would spin. It took me a while to figure out that was the problem. Maybe the SD-7/9s use the same drive shaft?
I bought two pair to replace the origional ones and that made all the difference in the operation. I miked the hexes across the flats and the new vs. old ones were nearly identical but the new ones cured the problem.
BLI reminded me not to switch the forward/reverse button while the engines are going at speed since this will round off the drive hex (AFAIK I hace never done this!)
If you have the shell off try holding the wheel while turning the flywheel by hand and look for slippage.
Just maybe... Ed
Thanks Rick
I have followed your suggestion and the wheels are certainly cleaner! That did not solve the issue of jerking motion, it conectivity seems better, but still on occasion just stops anyway. I received a new decoder from BLI , I did not think this would solve it but tried it anyway. There is quite a lot of oil around the trucks gear boxes though, which can cause issues. I will let BLI look at it.
The loco can run smooth for a few laps on my 7 foot by 7 foot layout. Then it starts jerking, more pronounced at faster speeds. Gear meshing issue maybe? I just bought a Atlas SDP-35 which is also same size as SD-7 with 6 axles, and it works fine. My 4 axle units GP-35s, SW1500, GP-40s work fine also. They vary in lengh so I hope BLI can see what I see.
Marty
Marty,
Just a thought, but did you try cleaning the locomotive wheels? I have had units, even factory new from the hobby shop, that needed a good thorough wheel cleaning done to perform well.... Easy way to do it, take a paper towel, lay it across the rails, wet the edge with isopropyl (rubbing) alcohol, 70% or higher, and run just one truck (either end) of the loco onto it. Hold the loco and towel in place for a minute, then slide the loco around on the towel underneath the running locomotive wheels to a new spot. If you see black smears on the towel, the wheels are dirty and could be affecting electrical pickup. Clean in this manner until there are no more of the smears of black gunk, and this should help the electrical pickup.
Ricky W.
HO scale Proto-freelancer.
My Railroad rules:
1: It's my railroad, my rules.
2: It's for having fun and enjoyment.
3: Any objections, consult above rules.
Hi Evertone,
I have a BLI SD 7 (6 axle) diesel loco. I have trouble getting it to run on my small layout. It jerks a lot and just stops at all areas on the layout. The faster it goes , it is more noticable. I thought it could be my track connectivity and leveling, which would be a big factor but all my other units including my latest 6 axle Atlas SDP35 run well without trouble. I also have 2 Kato GP35s, Athearn SW1500, 35 year old Atlas GP 40 converted DCC) which run fine. The BLI seems very sensitive when running on my layout. I used a DCC bus with 12 AWG with 20 awg branch lines every 18 inches on the bus and the Zephur plus throttle.
Anyone experience similar issues with BLI diesels of this size or other sizes.