Mysteries of the new LokSound in the Intermountain SD40-2

[jdcolombo]

Ok, ok. Let me refine my point.

I agree completely. They should make it as easy as possible to add them and decoders pre-installed in locomotives should come with them.

Agreed.  For factory sound installs, the manufacturer should add keep alive.  I've never seen a sound loco in N or HO that didn't need keep alive to avoid sound dropouts.  I remember that I thought I could get by without it when I did my first installations back in 2013; now all those locomotives have retrofitted keep-alive!

John C.

[Steveruger45]

Hi Guys,
Well as my loksound select micro for my kato sd45 sound install project is on hold due to very late delivery by USPS, I thought I would have a go at installing 400uF keep alive caps to one of my IMRC SD40-2 with the slide in sound decoder to fix the sound drop outs.

I could find only just enough space to fit four of the 2mm thick 100uF x20v poly tantalum caps at the rear of the frame.
To get enough room under the decoder I had to file out a space in the frame about 1 to 1.5mm deep just aft of the rear decoder contact claws.  There is a plastic frame spacer in the way at this location too and the top part of it has to be trimmed off.  You also have to cut off the aft part of the plastic decoder insulator mat. Space is very limited.

Now the caps just, and I mean JUST clear the decoder.  I wrapped the cap gang with kapton tape and put a piece on the frame too.

The caps Positive and negative wires were soldered to the purple and green points as Peteski had so heroically identified earlier in this thread.
You can see in the attached photos which ones I chose, which were the easiest to get to, IMHO.

1/64" solder tip was used here with my Weller soldering station.
These component are very small so solder with great care.

While I had the loco apart I took the trucks apart and cleaned up the dimpled contact strips with a tooth pick wrapped in some 2000 grit wet and dry paper to get all the factory blackening off all electrical contact areas.  While at it I also completely cleaned and very sparingly re-lubed the trucks gear axle points, worm bearings etc and put a very slight smear of silicone grease on the frame halves in way of the truck bolster points.  Just to be thorough I polished and shaped the copper contact strips a bit too.  Furthermore, I found the decoder was pretty slack in the frame claws, especially at the front.  So I built these up with a smear of solder on the top part of the contact pads. All this to be sure I have reliable electrical contact. 

In short, it now works fantastically and sound drop outs are now a thing of the past.

I would like to give a very big thank you to Peteski, for the work done and guidance given on where to connect the keep alive caps.


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[MK]

Very neat and orderly install.

[Steveruger45]

Thanks. The most difficult part was summoning up the courage to do it.

Anyhow, to let everyone know who may be considering this, pls note, there is absolutely no room to put the usual tantalum caps in this loco, they are far too tall.

At front, all space is needed for light tubes to ditch lights and next to nothing can be removed from the frame here.  Back aft the space behind the decoder is filled with rear light lens and a blocking bulkhead. You might and I mean just might get one tantalum cap at the very rear by removing some of the frame above the rear bearing block.
Where I put my caps you can't remove much more than I did from the frame.

Since this one I did my other sd40-2 as well with same great results.

[AKNscale]

Looks good, I do have 4 of these to do.

[peteski]

Nice job Steveruger45!
Good to know that the info I provided was useful to the fellow board members.

[Billg]

I could find only just enough space to fit four of the 2mm thick 100uF x20v poly tantalum caps at the rear of the frame.
To get enough room under the decoder I had to file out a space in the frame about 1 to 1.5mm deep just aft of the rear decoder contact claws.  There is a plastic frame spacer in the way at this location too and the top part of it has to be trimmed off.  You also have to cut off the aft part of the plastic decoder insulator mat. Space is very limited.

Steve, could you give a P/N of the caps you used and where you got them?  I would surely appreciate it!

Thanks,

Bill

[Steveruger45]

Steve, could you give a P/N of the caps you used and where you got them?  I would surely appreciate it!

Thanks,

Bill

Hi Bill,
Details in this post
https://www.therailwire.net/forum/index.php?topic=43836.msg560900#msg560900
Steve

[Billg]

Steve,

I took your advice and disassembled the 40-2 and cleaned everything.  Not too impressed with their truck assembly.  Quite a bit of "slop" everywhere and FULL OF GREASE!  This thing was packed with it!  The trucks would hardly free-roll at all.  I cleaned it all up and reassembled just to see if everything I did made a difference (waiting on caps) and it sure did!  Someone asked earlier why, for the money we pay, they came that way.  Well, China for one and I don't think it would be much fun, at least for some of us, if every engine ran terrific right out of the box.  I should say that this is my first Intermountain engine...probably won't be the last.

Bill

[peteski]

Steve,

I took your advice and disassembled the 40-2 and cleaned everything.  Not too impressed with their truck assembly.  Quite a bit of "slop" everywhere and FULL OF GREASE!  This thing was packed with it!  The trucks would hardly free-roll at all.  I cleaned it all up and reassembled just to see if everything I did made a difference (waiting on caps) and it sure did!  Someone asked earlier why, for the money we pay, they came that way.  Well, China for one and I don't think it would be much fun, at least for some of us, if every engine ran terrific right out of the box.  I should say that this is my first Intermountain engine...probably won't be the last.

Bill

I have never seen *ANY* Chinese-made model locomotive which had the correct amount of lubrication. They are *ALL* extremely overlubricated.  So much so that I often find the oil (either from the motor or precipitated from the gear grease) has oozed out onto the outside of the model's shell or even absorbed by the foam rubber nest the model sits in.  It is really bad.. They just seem to thing that more is better.  When I get a new model, the first thing I do is to take it apart, degrease it, then properly lubricate it.

[Steveruger45]

Steve,

I took your advice and disassembled the 40-2 and cleaned everything.  Not too impressed with their truck assembly.  Quite a bit of "slop" everywhere and FULL OF GREASE!  This thing was packed with it!  The trucks would hardly free-roll at all.  I cleaned it all up and reassembled just to see if everything I did made a difference (waiting on caps) and it sure did!  Someone asked earlier why, for the money we pay, they came that way.  Well, China for one and I don't think it would be much fun, at least for some of us, if every engine ran terrific right out of the box.  I should say that this is my first Intermountain engine...probably won't be the last.

Bill

Bill,
I see Peteski already replied and I concur absolutely.
One thing I found when sorting my two sd40-2’s out was not only the over lube issue but the blackening on the axle dimpled pick up strips and bits of crap in the wheels where there is a circumferential groove.
 Funny thing was, one loco had blackened dimpled axle pickup strips and the other was silvered. 
In either case I cleaned them to copper.
BTW
I have ordered 2oz of NoOxId special A.
I used to have this stuff for radio ham equipment deep in my past, but had it so long, nigh on 40 Years, I dared not use it anymore and threw it out a year or two back.
 I plan to put just the faintest smear of this magic elixir on all the electrical contact points on these loco’s. 
Do not over do application of this stuff, a little goes a very very very long way.  Wipe on let sit then wipe off.
Too much would be bad thing like too much lube in so far as it could be a crap magnet.
Once applied it needs to sit about a day to chemically bond. It really does improve electrical contact and protects from oxidation, which is a problem where I live in Houston what with the horrible humidity here.
I have never used it on model railroad stuff before.  I will probably do my track too after the next regular cleaning.
If anyone has any experience on using this stuff on model railroads I would love to know.

[Steveruger45]

/>
Here is video, of the sd40-2 after overhauling the trucks, fixing all the electrical pickups/connections and fitting the keep alive caps.

I hope this uploads ok, am trying YouTube for the first time.
Steve

[Billg]

Received my Caps today from Digi-key.  Can't wait to install 'em tomorrow.  I hope my dash 2 runs as well as yours Steve.

Thanks to all you guys for all your help!

Bill

[AKNscale]

/>
Here is video, of the sd40-2 after overhauling the trucks, fixing all the electrical pickups/connections and fitting the keep alive caps.

I hope this uploads ok, am trying YouTube for the first time.
Steve

This is before the NoOxId Special A though correct?

[Steveruger45]

This is before the NoOxId Special A though correct?

Yep, I haven’t received the NoOxId yet.  Although it will fix poor electrical contact to a good degree, this is IMHO a bit of a bandaid approach, so the idea is for it to maintain already good electrical contact from deteriorating due to oxidation/ humidity etc.