I purchased a new out of the box Non DCC equipped Kato SD40. The locomotive has a terrible buzzing sound on a DC layout in the forward direction with or without the shell on, that seems to disappear at high speed (Full Throttle). In the reverse direction the locomotive seems to run just fine. If anyone has experienced this and found a solution please share, other wise I will think I will need to send it back!!!
I have only had 1 or 2 Kato units that have had this problem. In my case, the problem was flash on a drive shaft next to the universal joint. Removing the flash stopped my noise. Another problem could be the motor not sitting properly in the motor saddle, which could cause one of the flywheels to touch the frame somewhere. Also look for metal flash on the frame in the flywheel area. Mark
I would agree with Mark, as the problem being flashing. I believe there is an earlier thread that discusses problems with this same Kato locomotive. It's possible this batch of locomotives got past the inspector or Quality Assurance person. Several, new SD 40's have been reported here, as less then, on delivery. I would contact Kato and discuss the problem with them. Seldom have I needed to send anything back. Usually it is a matter of ordering a new part Ie., a set of trucks. On another occasion... I had purchased a used locomotive and it needed work. I mailed it to them and they fixed it.
Thanks for your replies. I did find the problem. I changed my DC power Pack the one I use for test running new locos before DCC. I switched it out for the old one and everything worked as expected. Put back the new one and the problem returned. So must have an issue with that power pack.
I had a similar problem last year with a SD70MAC. Although I've never found the root cause, I disassembled everything, cleaned and lube and the noise was gone. It was probably something not sitting right. Could also be a flashing somewhere as Rick mentioned above. Now she runs absolutely silent, even on 9-3/4 curves!
After reading and rereading the problem Charles described. Noteing the sound disappeared when he used a different transformer. I got to thinking back to a problem I had recently. All my engines would humm or growl when the throttle was at zero speed. My son-in law the electrical engineer in the family, stopped by and he showed me, it was leaking AC. When I switched over to another transformer the noise stopped. I did start a thread here discussing the problem as it also caused a melt down on the switch throw rod, a Kato #6 switch. Hopefully,it can still be accessed if you are inclined to revisit the thread. Model Railroader recently produced an issue discussing AC leakage from a transformer pretty much refuting it. Sometimes I just think we have our heads, like an ostrich, in the sand. I could have put this differently but this sounds cleaner. Perhaps, we'd rather deny a problem is possible or exists as opposed to facing it head on. I don't know but every time I've run into a problem like this and shared it with other model railroaders, I get the same answer, "It's not likely this could happen...unless". Need I say more. My educated guess based on personal experience says the transformer you were using was leaking AC.
Rick Interesting, I think that might explain the problem. I noticed that the engines also got very hot. I will get the power pack plugged in and see if this is the case.
Some power packs put AC automatically at the lower portion of the throttle . This is they say to help doing a smooth start . When I was in DC , I was operating on smooth DC no AC at all . With good locomotives you don't need that , with cheapo locomotives of 15 or 20 years ago it helped them operating better and have lower starting speed .
AC to a Kato will destroy the motor! I speak from experience. Sold a set to a customer who also purchased a MRC power pack. He brought the loco back claiming it would not run at all and never did. We swapped it out. He brought that one back we tested both and neither ran here. Gave him a third and he brought that one back with the track an transformer. YUP he had connected the track to the AC - Accessories side of the power pack instead of reading the instructions.
George LOL George, That was expensive for you or him. I had it connected to the DC Terminals, but checking that out at low voltage there is an AC component present, how about that.That explains why the buzzing disappeared as the throttle was increased. In the reverse direction, no AC component was detected. This Power Pack has been shelved.
It is true AC creates that buzzing sound, that sound is your motor over time burning out! Many of the "home-made" throttle designs from the "early days" when technology started to "move" the hobby (like the pun?) utilized a potentiometer (spelling?) that you could adjust to pump some AC into the line allowing, you guessed it, those older 3 pole motors to turn over easier. It was trimmed so low that you wouldn't burn it out as if it were connected to full 12-16v AC, but over the long run it would dog the motor. My Dad made one about 20 years ago which he still uses...surprisingly he has many 20 year old locos that run. It even boosts the performance of 5 poles but DCC board performance its now useless. But to address the issue at hand its just a sad sitting saddle. :shade:
