The plastic nuts are tapered on the TIU posts. So although it may seem like a socket won't work, they will. It will almost keep you from overtightening them. I say almost because I have seen people still break or strip them.

 If you don't have a tool on hand when you're putting the spade in, just get it hand tight, and then rotate a little more using the spade itself.

 I wouldn't over worry about chewing up the posts as they are fairly cheap and easy to replace. You don't want to spin the posts inside too much causing more issues. I found many of my TIU posts were loose inside and I was more worried about the outside at first!

I took Barry's hint and got the banana plugs. I'm very pleased with them. I twisted a post off of a track power post by hand. I wouldn't even think about using a wrench.

You really want to make SURE the posts are very tight inside the TIU case!  If those connections are loose, the high current through the TIU will melt the posts and the case.  You probably remember seeing these pictures.  I've seen a couple of TIU's like this as well as a Z-4000.  All had the same issue, loose connection to the terminal inside the case.

I was surprised to find many of my 4 TIU's posts were loose inside and I never knew it. The most recent one, came from the factory with almost all of them very loose inside. I have to recommend that all users check the inside for this condition.

My Rev. L has red lock tight on them right from MTH. They must be aware of the issue.

Dave Zucal posted:

My Rev. L has red lock tight on them right from MTH. They must be aware of the issue.

It's about time!

This is not a problem on Rev G TIUs.  But anything later, it is.  Even my Rev L which had loctite.  In my opinion, the loctite fix isn't worth doodlysquat.  As I've said elsewhere, tighten the nuts with a wrench.  Over the nuts place internal star washers, and then add a second nut.  They are metric sized, but readily available in many hardware stores.

Banana plugs !!!

Eliot, banana plugs do nothing for the problem that the inside connections are loose in the TIU.

Should I open my new TIU to tighten the nuts?

John,

banana plugs do nothing for the problem that the inside connections are loose in the TIU.

Agreed. The use of banana plugs is primarily to facilitate ease of changing connections.

However, using them cuts down on the use of the thumbscrews, thereby reducing the possibility of any loosening as a result of connecting or removing wires. I've always used banana plugs exclusively on all TIU channels and have never experienced any issues resulting from loose posts. Good "luck of the draw" most likely plays a part, as well.  

FWIW, I always tighten the exterior posts of all TIU channels before placing a TIU into service.

Bob, I would so recommend, but have lock washers and nuts on hand so you never have to do the job again. 

When tightening nuts, don't overtighten to the point that you crack the plastic. 

Bob Shaw posted:

Should I open my new TIU to tighten the nuts?

 

YES!

Like RJR says, add the lock washers so it's the last trip in.

There isn't a lot of danger in cracking the plastic, the nuts tighten against the binding post holder, it's a separate piece with the two posts on it.  I use a little Ignition system wrench set to tighten them, the wrenches are about 3" long.  No danger of getting too tight with those.

Unless they are grossly loose, just tighten another half turn.  G

Nut size is M4-.70 .  I got them at a local Ace.

After tightening the existing nuts, I use internal star washers to bite into the original and the added nut.  External star washers won't bite into the nuts.  I prefer these to split lock washers because they have many biting teeth.  2 wrenches must be used, one on each nut, to tighten them together.

Bob Shaw posted:

Should I open my new TIU to tighten the nuts?

 

I'm wondering the same; even if we've not seen a problem yet, should we open up the TIUs and check that these posts are tight?  I use banana plugs into them.

I can only say that I've opened all of mine and the club units.  All needed some tightening of the posts.

Kerrigan, if you see a problem, it's too late.

Great information here! Thanks to all!

Dave Zucal posted:

My Rev. L has red lock tight on them right from MTH. They must be aware of the issue.

Mine has blue, but not the Locktite(tm) I've used for years working with automobiles.. Got to be some sort of Chinese 'knock off' stuff.. IMO worthless.....

Loctite is useless if the nut isn't properly tightened.

Went into my new (REV L) TIU this morning.. All the posts needed tightening.. FWIW, I took RJR's lead and added the extra nuts  and washers as he suggested.. After all, I was "already in there" and certainly won't hurt anything!! Again thanks to all of you for your help and guidance.. This is one less potential problem to worry about!! BTW, 7mm is the wrench size and be careful not to over tighten the little phillips screws (6) that hold it together......

RJR posted:

Kerrigan, if you see a problem, it's too late.

Good advice.  Another item on my layout to-do list ... soon.

Been putting it off as I need to haul them out from under the layout.   A plus is having the banana plugs.

A star washer with an added nut on top of it, correct?

Yes, but note the washer needs to have the teeth pointing towards the center.  I tried at Ace, and realized those with the teeth pointing outward would not dig into the nuts.  Note also that they probably don't have metric star washers, so use the non-metrics that fit the closest over a screw that the nut fits. 

When working in the TIU, be careful as there is little clearance on some to get the wrenches in.  Also, thin wrenches---ignition wrenches as GRJ says---may be needed for the inside nuts.

I'm not a fan of banana plugs, because I'm not sure they have enough contact surface.  I've been using crimp-on spade connectors, but that's not may favorite device either.  See the attached, which had been subject to 18-amp loads in an A/C.

RJR posted:

....

I'm not a fan of banana plugs, because I'm not sure they have enough contact surface.  

That's the best thing about the banana plugs. Just use the snug fitting ones.

I've never had one fail in the last 38 years of using them.

On a good quality banana plug there is definitely more surface contact area than a spade lug on a binding post.

You can also find locking ones that "tighten in the hole" (the tip is made to expand)

Never had problems with ones up to 20 amps.

Greg

this wrench works well. 9/32 both ends.

Thanks all for your inputs. I opened my TIU and tightened all the internal nuts 1/8 to 1/4 turn with a 9/32 wrench. Decided to take a chance without the second nut because I was too lazy to get metric nuts.

Then I finger tightened all the spade wire connectors onto the appropriate external plastic nuts until they were real firm. An slight additional  turn with needle nose pliers was added.

I think attaching the TIU is important precaution to preventing the nuts from loosening. So I removed all the rubber pads and drilled out the holes with a 1/8" bit. Then I used #4 screws to attach the TIU upright on a leg of the table.

 The best lock washer period is the European lock washer. Also known as a wave washer, warped washer, etc.

  It looks like a washer curved from flat in a vice. It's O.D. still flexes when flat,  holding the bottom edge of two flats on the nut, and the opposite two side press down to hold onto the surface.

I discovered them decades ago on those "funny little German cars". I shudder everytime I use an American locking split washer now, which you can rarely get flat by fingertips anyhow, even small sized. Overtighten it and the American lock washer opens, and gets pressed out from under a nut.

  They only come in metric form that I've ever seen. But, for use on American screw/bolts, "close enough" has always been 'good enough'.

Usally more expensive, but worth it. Mostly the extra pennies are because they have to be made to be a "soft spring steel". Hard enough for the grade, but retaining flexibility too. I could flatten them by fingernut if about 6-7mm or less. No need to over-tourqe, but if you do, your washer will almost never pop like a split would.  

  They are a hard metal (over our grade 10, Euro grades are different) and so they do split on rare occasion. I bet I have had less than 20 split in 30 years and more than a few thousand applications. Usually exhaust on modded motors where a hard grade is actually at risk from the heat (used there, slightly softer is usually the key)

Anything I built for offroad got them, ....everywhere. It later carried over to animatronics and games repair. If you have that much vibration that these come loose with locktite, you need to move away from that fault line.

Use high temp locktite red. To remove a nut for repair, use a soldering iron or micro torch to heat the threads SLIGHTLY. The locktite will soften to a stiff goo and be removable. I pulled this off with grade 5 hardware (except for that lock washer) under ¼" dia., right next next to wood and sometime ON wood, maybe twice a week for years. My end result had to publically "abused" all day,  proffesionally acceptible, and my judges were not "easy" to please. 

Inside and outside star washers have their place. Not my fav. but ok for low tourqe like this. Once tourqed, espcially by wrench, those tabs are bent unless the seating surfaces are softer than the star washer. Not made for reuse imo, and often not as stable either having less seating area, but better than a split washer.

  If the wires arent yanked on, I would likely use a regular old flat washer and be fine.....never really knew if I was that good or that lucky but for static items thats all you really should need. The locktite is overkill really, but I hate doing stuff like that twice.

Bob Shaw posted:

Thanks all for your inputs. I opened my TIU and tightened all the internal nuts 1/8 to 1/4 turn with a 9/32 wrench. Decided to take a chance without the second nut because I was too lazy to get metric nuts.

Then I finger tightened all the spade wire connectors onto the appropriate external plastic nuts until they were real firm. An slight additional  turn with needle nose pliers was added.

I think attaching the TIU is important precaution to preventing the nuts from loosening. So I removed all the rubber pads and drilled out the holes with a 1/8" bit. Then I used #4 screws to attach the TIU upright on a leg of the table.

 

Good move Bob. We just drilled right thru the case and the rubber feet to attach them. IIRC I used the RealTrax rubber feet to add some cushioning squeeze. Need to update the software in them so I may remove them and work on tightening everything and adding the lock nuts at the same time.

Adriatic posted:

Use high temp locktite red. To remove a nut for repair, use a soldering iron or micro torch to heat the threads SLIGHTLY. The locktite will soften to a stiff goo and be removable.

I like the wave washer idea, but I have to take exception to this suggestion.  It's overkill for the TIU posts, which is what we're talking about.  I use Loctite Blue Threadlocker, more than sufficient IMO.  With all that plastic around, I'm not a big fan of needing heat to take it apart.

I think attaching the TIU is important precaution to preventing the nuts from loosening. So I removed all the rubber pads and drilled out the holes with a 1/8" bit. Then I used #4 screws to attach the TIU upright on a leg of the table.

 Agreed: Attaching the TIU to something firm will help prevent connections from wiggling and loosening. But I go one step further: What I do is remove the top (6 small crews in the bottom) and drill out all 4 corner holes to accept screws. Pick a flat head pan screw  (you need 2) with a head just small enough to fit in the tube above the rubber pads. The hole you drill should be big enough to allow the screw threads to pass through but small enough to prevent the screw head from passing through. Mount the TIU base (top off) to a board using a top corner and the opposite bottom corner. The screw head should go into the tube and bottom out, securing the base to the board. Then use longer screws of the same diameter to mount the top to the base using the opposite unused holes in the corners. The screws go completely through the TIU and bite into the wood broad behind the TIU. Use a washer to insure the screw head does not go into the hole. Now when you blow a fuse, you simply remove the 2 screws with the washers and the top pops off, and the base stays put. No need to dismount everything and pull the 6 little screws out of the bottom!

Chris

LVHR

BobbyD posted:

Bob Shaw posted:

Thanks all for your inputs. I opened my TIU and tightened all the internal nuts 1/8 to 1/4 turn with a 9/32 wrench. Decided to take a chance without the second nut because I was too lazy to get metric nuts.

Then I finger tightened all the spade wire connectors onto the appropriate external plastic nuts until they were real firm. An slight additional  turn with needle nose pliers was added.

I think attaching the TIU is important precaution to preventing the nuts from loosening. So I removed all the rubber pads and drilled out the holes with a 1/8" bit. Then I used #4 screws to attach the TIU upright on a leg of the table.

 

Good move Bob. We just drilled right thru the case and the rubber feet to attach them. IIRC I used the RealTrax rubber feet to add some cushioning squeeze. Need to update the software in them so I may remove them and work on tightening everything and adding the lock nuts at the same time.

Strapped them to the board with zipties.  Works great and I can remove than at will without hassle.  Holds them down tight.

gunrunnerjohn posted:

Adriatic posted:

Use high temp locktite red. To remove a nut for repair, use a soldering iron or micro torch to heat the threads SLIGHTLY. The locktite will soften to a stiff goo and be removable.

I like the wave washer idea, but I have to take exception to this suggestion.  It's overkill for the TIU posts, which is what we're talking about.  I use Loctite Blue Threadlocker, more than sufficient IMO.  With all that plastic around, I'm not a big fan of needing heat to take it apart.

On the other side of the coin:  I've run 3 TIUs for 10 years without any problems and not taking them apart.  They are strapped onto the  board to keep them from moving around.

Kerrigan posted:

gunrunnerjohn posted:

Adriatic posted:

Use high temp locktite red. To remove a nut for repair, use a soldering iron or micro torch to heat the threads SLIGHTLY. The locktite will soften to a stiff goo and be removable.

I like the wave washer idea, but I have to take exception to this suggestion.  It's overkill for the TIU posts, which is what we're talking about.  I use Loctite Blue Threadlocker, more than sufficient IMO.  With all that plastic around, I'm not a big fan of needing heat to take it apart.

On the other side of the coin:  I've run 3 TIUs for 10 years without any problems and not taking them apart.  They are strapped onto the  board to keep them from moving around.

I got a brand new Version L in. I opened it up and found most of the terminals were loose. By your suggestion, I could have waited until things melted.

If there's a known issue like wires rubbing on flywheels, I would not be the one to suggest that everyone should ignore it and just handle them better.

Joe, I've actually fixed several that have had the case melted sufficiently that I could barely fix them, and they looked a bit "wrinkled" when they were returned.  I'm saving a scrap TIU for parts, I've already used a bunch of the terminals, and one day I'll get one that the case is so melted that the spare case will get used.

gunrunnerjohn posted:

Joe, I've actually fixed several that have had the case melted sufficiently that I could barely fix them, and they looked a bit "wrinkled" when they were returned.  I'm saving a scrap TIU for parts, I've already used a bunch of the terminals, and one day I'll get one that the case is so melted that the spare case will get used.

Thanks John.

BTW, you know I was talking about Kerrigan's post right?

I bet if we didn't draw many amps and we used banana plugs, we might get away with them slightly loose. I have loaded mine down pretty well running many engines and lighted cars at a time. If I didn't tighten mine, I would have had a TIU for your case!

They can get loose even with banana plugs.  And they may be loose from China.  I would open a new tiu and do the lock nut fix.  Actually, I did and found them loose.

The vibration of trains running may loosen connections.

Joe, nuts wouldn't be a problem if we didn't hook up the tius.��

This is a bit disturbing...  I recently purchased my first TIU (dealer new Rev. L) .

Are there any telltales that would indicate they are loose?

Will opening it void the warranty?