I just bought a HO Bachmann 70 tonner for $60 with DCC onboard at the hobby store. I runs decently but compared to a HO Bachmann SD40-2 I have, it has quite the growl. Is this normal and just need some running in? Is there any way for quiet is down a little or do I need to send it back to Bachmann?
That’s not a growl, that’s a Sound-on-Board Bachmann…[;)]
Yeah, I’ve a got a few of them, all narrowgauged to HOn3. They are little coffee grinders, and I actually do tend to think of the noise as a sound effect, crude as it may be (“Where’s the Horn button?”)
Now, if it’s extra noisy, there may be a problem. It’s worth popping the gear covers off the bottom of the trucks to check the lube situation. You want it fresh and not excessive. I use oil, but some use grease, gotta be plastic-compatible. Under the hood, make sure everything looks in place, again, light lube preferred.
BTW, the decoder’s good point is it was free. The problem is it was free and that’s been my experience of its value. Something cheap in almost any other flavor will be world’s better motor performance. You’ve been warned…[li]
I actually found I could hack the NCE BACH decoder board into something that works quite well, because it provides an easy way to get functionality for the rear headlight. I ordered these thinking they’d work in the 70-tonner, but they’re designed for road-switchers and other longer locos. They’re just too long for the little GE. But this hack solves both problems at once.
Here’s some pics of how I did it. The upright piece of PC board in pics 4 & 5 that holds the rear headlight is recycled from existing parts in the 70-tonner. The trickiest part is cutting most of the way through the PC board, then bending it up, without damaging the traces. I added the resistor for the headlights, but if you’re an electrical genius, you could probably repurpose one already on the board? Just trace the wires on the BACH decoder from the pics and all becomes obvious. After all, I figured it out.[:D]
[URL=https://imageshack.com/i/mu6o5cj][IMG]http://imagizer.imageshack.us/v2/1280x1024q90/82
Thanks for the help. I was getting a little worried. I do say it definitly sounds like a coffee grinder on rails. I should also mention I’m running it on straight DC (the decoder is dual mode)
It very well may run fine on DC. I did not try that. It seems to be a decent light board.[:P]
It’s a good little deal, even with the odd DCC performance. I wasn’t griping, just putting up a solution. Obviously, with DC, if it does give you any issues, then I’d just take it all out and hardwire it.
The loco is fine! The decoder is CRAP! Replace with decent decoder and instant more silent loco!
Respectfully, the OP indicated he is using the loco on DC - why would he buy a new decoder?
But, you are correct, the decoder is crap.
For DC operation the best plan is to simply bypass the decoder section of the circuit board - that is what I have done with my small fleet of Bachmann 70 tonners - and they run great on DC and are much more quiet.
In fact, out of the box, a Bachmann DCC onboard 70 tonner with not even run at all on my Aristo Craft Train Engineer wireless radio DC throttles - they just sit there and buzzzzzz.
To the OP - if you would like to know how to bypass the decoder section of the circuit board, let me know, I will dig out my notes on the subject and post them on here.
Sheldon
Its not the decoder…My 70 tonner ran quite smooth in DC until I took the trucks apart to cleaned the gears and after reassembly it sounded like a coffee grinder…I disassembled the trucks and carefully reassembled them…Now its smooth running.
Larry, it depends a lot on what kind of DC you are using. Most all decoders, cheap or expensive, do not work well, and make noise, on my Aristo Craft Train Engineer throttles - because they use pulse width modulation motor control.
Sheldon
Sheldon,I notice one of my Atlas DCC equiped Gp38s makes a very slight humm(to my hears) when ran at the club or on my Tech II but not the Tech 6 in DC mode.My older Atlas dual mode engines doesn’t make noise when operated in DC mode.
I use a MRC Tech 6 and it is in IMHO superior to any regular power pack including my 24 year old TechII 1400 which is still a worthy power pack for simple DC operation…
Larry,
My 70-tonners ran noisy before and after conversion to HOn3. Trucks were apart, reassembled, and cleaned several times in the process, so I doubt I missed anything. I’m comparing them to my Kato NW2M conversions, though, which is really apples vs oranges. “Coffee grinder” noise is relative and they are easy to take apart and reassemble, so it’s well worth going through the geartrain just to be sure it’s as good as it gets.
Larry, as “stationary” power packs go, the Tech 6 is an excellent piece of equipment. But the Aristo Train Engineer provides a wireless hand held with even better slow speed control.
With the push button control, it provides very smooth starts and stops becasue it “ramps up” and ramps down - even when you push emergency stop.
And the pulse width control turns most headlights to full brightness even before the loco moves.
Sheldon
I would greatly appreciate it is you would.
Yes, that would be good info to have, then that decoder will make something useful out of its miserable life – a good light board.[;)]
OK, give me a day or two and I will also pull the shell off one and take photo of the modifications, I don’t recall the details without digging out my notes, but I remember it was rather simple to do.
I have the grand children today, so if I run off to the train room withthe camera, the wife will give me one of those “looks”. But I will get back to this this evening or tomorrow evening.
Sheldon
OK, sorry to be so long getting back to this, but snow and work and grandchildren all had me busy.
I tried to take some photos, but clearly my photo skills need work because I was unable to get a picture where you could actually see any detail of value to this conversation.
So here goes a step by step description.
The circuit board is clearly marked with a number of references I will refer to, front being the low hood end, etc.
Remove the shell and the weight on top of the circuit board. Note the markings on the circuit board for the truck pickup and motor connections - I will refer to these as we go along.
Remove the circuit board to make it easier to work on.
Remove the three surface mounted diodes near the front of the board, marked D3, D4, D5. They can be removed by simply breaking or popping them off with small pliers.
Cut the negative lead of the front light LED near the circuit board, bend the remaining lead up away from the ciricuit board, solder a short piece of small wire to the lead of the LED. This wire will reconnect to the left side pickup connection when you reinstall the board.
At the rear of the main board, there is a small vertical board with a surface mount LED for the rear light. Looking at this board from the rear, you will see that the right hand connection is the negative lead of the LED. Solder a short wire to the negative lead of the LED at the point where the two boards are joined. This wire will connect to right side truck pickup.
On the bottom rear of the circuit board, you will find a thin circuit trace comming from that negative lead of the rear LED - cut this lead by scrapping it with a knife. OR, if you leave this connection, the front headlight will stay on in both directions, and the rear one will only come on in reverse.
Reassemble the loco - new connection as follows:
Left front connection - left front truck and new front LED wire
Right front connection - right front truck a
Sheldon,
Thanks, good info to have.