Zimo

I recently received an MX645 sound decoder and fitted it to a new Bachmann H1/2, South Foreland. A very nice looking model it is too. For the first time ever with a Zimo decoder it ran like a three legged goat. I took the loco body off and noticed that it's probably a geared drive to both axles, resulting in the coupling rods just going along for the ride.

I found three capacitors and two inductors, so off they all came, soldering the wires direct to the motor. A 98% improvement. At speed with six MK1's on, it runs beautifully and sounds good but at low speed it seems as though it has a tight spot. I saw that the rods are a really close fit so eased them apart very carefully and while I had the body off gave a light oiling to the motor bearings and a spot of good quality silicone grease on the worm.. another improvement, but still not quite right. I suppose I'll have to bite the bullet and take the keeper plate off and check for a cracked gear.

I reckon that on the law of averages I should have some better luck soon. :)

[user=1120]peterm[/user] wrote:

I reckon that on the law of averages I should have some better luck soon. :)

Yep, you do have a reasonable amount of luck and I'm sure the change in quality will do you good. Just keep hold of it!

Best,

Bill

 :thumbs

I'm still upright and breathing, so luckier than some.

Now you've worried me Pete - I use the MX 645 but haven't had any noticable problems with Zimo.  I do note this is the first time you've encountered any but on the Zimo forum there's a discussion going on about a lack of compatibility from their new MS range on large scale locos ……………….

I do hope they're not becoming complacent.

Hi Pete,

That chassis looks similar to the one that went into the City class. That one from memory was tight until a few hours running and some oil on the rods/pins. I ran it with an ESU decoder. If you switch the Zimo for a known good running decoder does the issue persist? Same if you just run it with DC? Is the issue in both directions? Something to be said for running them in on DC.


If this is a new model I doubt you have a cracked gear shaft. Easy enough to check without removing the keeper plate. The other thing to check are the wiper locations. They need to be on the rims. An intermittent catch on a wheel spoke can happen. The City had wipers on the bogie. Least said the better.


Nigel

Thanks for the replies,

 Peter,
Don't you go adding to my worries. I hope I haven't come across a problem that causes me reason to send another decoder back to Austria. Is there any chance you could direct me to the post's about the MS series?

Nigel,

I'll give it some more running in time with my fingers crossed. I had a cracked/split gear on a brand new Hornby 9F, so not ruled out yet. Swapping the decoder isn't easy, not only because I don't have another one, but also I've had to hard wire along with mod's to make it fit.

Hi Pete,


The DCC version comes with a Zimo decoder.  I always rewire with a decoder plug after running in with DCC. One of the hazards of directly wiring a decoder to the motor is that it if something goes wrong it gets difficult to identify the cause. The Zimo you are using should work fine with DC.


Nigel

Hi Pete,

Just a thought - do you have a rolling road? Running at slow-speed should identify a tight spot. I just checked my notes on the City class. One wheel set was very slightly out of quarter. A very judicious repositioning of a wheel helped a tad. What did help most was running it at 40-75% of full power on DC for one hour in each direction. That appeared to be enough to clean up the bearing surfaces on the chassis (often ignored, they often have small spurs, I note I gave them a once over with some 1000 emery) and make sure the rods were not tight on the pins. I did relube with plastic compatible oil and grease afterwards (Labelle products). Bit like running in a car engine after replacing the bearings and rings. That and cleaning and repositioning the wipers so they only contacted the inner rim of the tire. 


The other thing I noted was the wiring connections between tender and locomotive were very poor, I redid them all. 


That really is a nice looking Atlantic model. 



Nigel

Thanks Nigel,

No rolling road, but it has had a good running in in both directions at the speeds you mentioned. More running in to come with fingers crossed. The quartering is the thing I don't like playing about with, so I'm hoping it's just about anything else.

I'll try to find the posts on compatibility problems again Pete - as they didn't really interest me, I deleted them as I went along.  They'll be in my "bin" but accessing them on this tablet is not something I'd relish.  They may be on my desktop which is a far more friendly beast.

Does this work Pete - it's just a single post in a whole conversation……….This post in fact refers to an MX decoder but it all kicked off with the MS range and, on re-thinking, it mainly related to compatibility with them and their MX10 controller……. :hmm


https://groups.io/g/ZIMO-DCC/message/8024

[user=6]Petermac[/user] wrote:

Does this work Pete - it's just a single post in a whole conversation……….This post in fact refers to an MX decoder but it all kicked off with the MS range and, on re-thinking, it mainly related to compatibility with them and their MX10 controller……. :hmm


https://groups.io/g/ZIMO-DCC/message/8024

 

Thanks Peter,

Yes that made sense but I don't think it's that. I gave it a good run yesterday and It'll get another one tomorrow.

I'm pretty sure it's mechanical, but finding and curing it's not going to be so easy.

Hi Pete,

Quartering: Many a quarterer has been quartered when quatering. OK if you have a decent jig, otherwise….that's why I like Markit's wheels and axles. And diesels.


Might be worth checking the idler gears to see if there are rough spots on the metal walls. Or a missing tooth.  You have more patience than me, new model or not, it would have been completely stripped down and everything checked out by now. 


Are the piston rods/cross heads tight? Are the cross head beams tight? Is the piston block square on? Are the wheels square on to the axles? (Just going through some of the issues I've had in the past). What happens if you put some weight on the engine? (Bean bag with some shot). Is the CofG over the drivers? (Common issue with Atlantics as the torque shift weight from one side to the other). Is the driver gauge OK? Ditto the track.


Nigel

Having checked just about all of what you've come up with I'm looking at gears now. I'll let you know how I get on.

Hi Pete,

But wait, there's more….


Are the wheels/gears tight on the axles? if they rotate with finger pressure…


Looks like it could be the gears. I've had a few Bachmann USA split gears on new stock recently.


Nigel

Wifies Birthday today, out tomorrow, so I'll get back to it when I can. I'll be back with a progress report.