TIU question

Peter,

First a caveat, I am new and trying to work though my own TIU problems, with that said, my TIU has 4 fuses mounted on the board. if it was me I would unscrew the 6 screws in the bottom and pull the cover off and check the fuses.

Blake

 

 

 

 

Blake has the correct answer, that's the first thing to check.  If you are blowing those fuses, you need better circuit breaker protection between the transformer and the input to the TIU.  They're standard 20A automotive blade fuses.

 

I'm actually out and about. if not too much trouble, does anyone know what type or size (I'm not an electrical guy) fuse I would need so I can go to Home Depot or Lowes and just get some before I head home later?  Or maybe the ones they sell aren't good enough?  If so a recommendation would be very appreciated. Thanks again!  Peter

I don't know if they are special or not. I think they are 20 amp (lime green)? small auto fuses? U shaped.  maybe, I don't know because never had to replace them.

Blake

I know they're the same size as the spares I have for the cars, but I don't know the exact model number of the fuses.

 

Here's a quick picture, got these from MTH a couple years ago when getting some other parts. So far, haven't had to use one. I can't see any numbers on them?

 

Hey - thanks EVER so much!  Unfortunately the guy at HD only had big variety packs so I will just take out the fuse tonight and go to auto store tomorrow to get a few of the exact one only. Thanks again! 

Gunrunnerjohn - your earlier post piqued my curiosity.  I purposely bought a very good surge protector strip for plugging things in.  And I purposely bought the Lionel 180 PH bricks because they have good protection too. But I think I have a weakness in my set up - and hadn't realized this before. Basically, I have one Lionel 180 PH brick for each TIU channel. So I have one PH connected to each "in" post (those in use) on TIU. I have MTH banana jacks on the "out" for each channel going to a respective MTH terminal strip. I have 14AWG star pattern wiring directly from the MTH terminal strip out to each track block. So broad brush - a wire from the PH to the TIU "in". A wire from TIU "out" to terminal strip. A bunch of wires from each terminal strip out to track blocks.  Where would I insert a fuse protector or whatever in this set up to ensure this doesn't happen again?  Appreciate "Barney style" solution and reply (if it exists) as I'm not an electrical guy and my skills are basic at best.  Thanks!

Where would I insert a fuse protector or whatever in this set up to ensure this doesn't happen again?

In the Hot wire between each power supply and the TIU's inputs, one per TIUI channel.

 

This and a whole lot more is all in MTH’s “The DCS O Gauge Companion 2nd Edition", available for purchase as an eBook or a printed book at MTH's web store!

The fuses are ATM "mini" automotive type. A better bet than your home improvement center is a local auto parts store.

 

Steve 

Well, I opened the TIU and realized I have no idea how to determine a blown fuse. One of them has a black spot in it.  Guessing this is the victim?  Also occurred to me as I started to tug on it and the thing wouldn't come loose but the entire green circuit board started pulling - I have no idea how to dislodge it.  Is it a simple "tug at the top of it till it slides up and out?" Or?  Last thing I want to do is manhandle it and destroy it. These things ain't cheap. Peter

You can measure them with an ohmmeter. The one with the black spot is probably a clue.

 

With the PH180, I'm amazed that the fuse blew.  I have the same setup, and we also have it at our club.  We've never lost a TIU fuse, and we have plenty of track shorts from time to time.  The PH180's always trip on the spot.

 

To get the fuse out, hold the board down next to the fuse and wiggle it free.

 

 

John, ohm meter - why didn't I think of that?!  Ok. Will do. Thanks. Just being very cautious for once, as my wife calls me "destructo" and I often live up to that name.  Peter

Thanks to everyone for all the help. Hoping to get things back up by tomorrow night. Will see ...

PJB,
    Even with modern transformers I recommend a Scott type bank of 10 Amp resettable breakers in front of every TIU port, the 10 Amp breakers can be reset when this problem occurs.  This eliminates opening up the TIU to replace the internal fuse.  I use this method to safe guard my TIU's all the time, especially with the old Lionel ZW & KW transformers, with their slow acting breakers.
PCRR/Dave

]

Dave - do you have a photo of the thing and how you have it hooked up? 

PJB,

   Yes I do and I tried to copy and post a picture for you from my photo bucket account

but for some reason today the OGR will not let the picture post on the main screen.

I have a question in the Tech section for Rich about this, in the picture posting section.  However what you need to do is place the Scott type 10 Amp breakers in front of your TIU between your TIU & transformers on all red channels.  This keeps

the TIU safe, the 10 Amp breakers always pop before the fuse in the TIU, in this manner you just power down the transformers, reset the 10 Amp breakers and power up again.  This keeps you from having to replace fuses in the TIU and safeguards the TIU from the old ZW & KW type transformes, which do work very very well powering a DCS layout, even though my Z4K has nice light breakers, I have a 10 Amp breaker in front of it also.

PCRR/Dave

Dave - there's apparently more than one Scott electric out there.  I just got off the phone with one and they said "must be some other Scott electric, we're a wholesaler."  A photo and/or web-link would be most appreciated.  Maybe you can send the photo to my email if it won't post here?  its pbilelis@yahoo.com.   Thanks for chiming in. 

 

Peter

I think PCRR is talking about these.

 

Circuit Protection

 

I also have to go with gunrunnerjohn's findings on the PH-180's built in breakers, I use them too. The PH-180 has excellent breakers. I don't have any of the breakers in the link, but I can't see these being any faster or better than the PH-180's, if even as good.  I think these were meant more for stuff like the older postwar ZW's and similar old style transformers that take a very long time to trip. They might even help with a Z-500 or Z-1000 brick as (in my experience) those don't trip near as fast as the PH-180's, which are virtually instant.

 

Not sure how you managed to blow the TIU fuse without tripping the PH-180? Could be a problem with the breaker in that brick? I am not an electrical wizard, just going by my own experiences here. On the other hand, I guess a little extra protection never hurt anything.

Thee is a weakness of the PH180 circuit breaker.  It's an active circuit, and if the circuit malfunctions in any way, the breaker will not trip.  The breaker is "tripped" when the relay is energized, it latches until a power cycle or you push the red reset button.

 

I have seen a PH180 with a defective breaker circuit, overloads didn't trip it.

 

Of course, a malfunction can happen to any circuit breaker, and the ones I have and at the club are reliable enough that I don't feel the need for more circuit breakers for the power from them.

 

I'm using the PSX-AC's as additional breakers along with the PH-180's. Those are impressive. And I was really feeling safe until reading your post above. Now I suppose those could fail also?  So in the event of a breaker failure, a fast blow fuse would then be the ultimate in back up protection?  Like one rated a couple amps higher than everything else?

 

(Not trying to re-kindle your interest in the PSX-AC's or anything here )

PJB,

   Scott's Odds & Ends was bought out by TrainElectrics, LLC Electrical supplies for the model Railroader, they are on the Web, and they still make the Scott 10 Amp breaker bank,  but have discontinued the 7 & 5 Ampers.    Unfortunately they list no phone number on their web sight now, you must

send them an e-mail and they will call you.  Or you simply order from their sight. 

PCRR/Dave

 

You can see the Scott 10 Amp Breaker Banks in front of the transformers in the picture below, with the 4 breaker buttons & white strip in front of them.

The odds against two sets of protection failing are about the same as you getting hit by lightning, so I doubt I'd lose sleep over it.

Thanks for all the advice!   I believe the 180 PH did trip but not sure. The first thing I did when there was no power to the main line was reset it, assuming that was the issue. But for all I know it didn't need to be reset.  But as an update, the problem (after cross examining my twins a little) was not as originally reported. They didn't accidentally drop some metal object on the track.  What actually happened was that they touched a screwdriver to a metal terminal port on the MTH terminal strip while the layout was electrified. It sparked and then that main line went dead, with the train on it shutting down.  So just to refresh everyone on my set up, each 180 PH goes directly to TIU "in" port and then I have banana jacks on TIU "out" ports right to each MTH terminal strip. And each terminal strip has 14 AWG wires running right to each track block (star pattern).  As I'm not an electrical guy, not sure if this makes any difference in determining whether the 180 PH did what it was supposed to or how to even assess if things are working correctly given the TIU fuse did in fact blow.  Peter 

If you get a high enough instantaneous current surge, you could take out the 20A fuse before the PH180 could trip, it all depends on the impedance of the short.  Shorting the bus close to the feed may explain why you took out the fuse.

 

I just tried an experiment on my bench with a PH180 and some 20A 3AG glass fuses, since I have a bunch of them.  If I short the output with about 40 feet of #16 wire between the short and the fuse and PH180, the PH180 breaker trips and the fuse remains intact.  I did this 10-12 times, never lost the fuse. 

 

If I short right after the fuse, leaving out the 40' wire, the low impedance short takes out the fuse before the PH180 reacts.  Two out of five times, the PH180 also tripped when the fuse went, the other times it didn't.  However, every time the fuse was blown.

 

With this and your post to PJB and also PJB's post, I feel better now. Probably won't add any fuses. At least in PJB's case kids will be kids and nothing but the fuse was damaged. Probably a good learning experience for the kids too, they may not do that again. Especially after the cross examination from Dad. I learned a few things that way myself back in the day, but they had much harsher cross examinations back then (belts, switches, etc.)!

 

Most of the PSX-AC tests I have done were from shorting the track which was connected with about 18" of wire. It always trips first that way. On one of my tests I shorted the PSX-AC directly at it's output terminals, got a very nice spark on that one and it also tripped the PH-180. Nothing was damaged, but only did that one time. It was back to the track after that as I didn't want to toast anything.

 

As far as 'sparking' your interest in the PSX-AC's, I'll have to keep trying with more subliminal messages (please see above paragraph).   

Gentlemen,

   I have used the Scott type 10 Amp breakers and the TVS built into the TIU for many years on all my layouts, and never had one problem safe guarding my layouts.  To me there is no need for over kill.

PCRR/Dave

 

Kids, screwdrivers and electricity. Not a good combination. The one item that would make it even worse would be the addition of water.

 

I recommend that you get your kids some Legos!

Terrence L,

    Nope just a little more parent supervision required, let the kids develope their engineering skills thru quality play time, with the train layout!  The world needs more chief engineers, especially today, legos don't make it happen.  The price for a Chief Engineer starts with layout damage thru experience.  Never knew a NASA chief engineer who did not start his education at a very young age, building O guage train layouts.  Every single one as a child started his education in this manner.  O Gauge trains are more than just a hobby, an engineering learning experience like no other.

Burn the Legos at age 10.

PCRR/Dave

I have  a fuse box, in the drawer, and also the 15 amp fuses,  just covering the bases,

I will have fuse protection between the Tiu input, and ZW, Transformer: And I ( still) already have fuse protection between the TIU output and all tracks, and TVS on all transformers,   anything else,  thanks

Please no wise cracks of TV commercial nature,  just inquiring is there any other places, for fuse protection,  ( my light accessory  circuits are fused also)

Command base ?????? yes / no !

TGP,

   I recommend 10 Amps instead of 15's, IMO there are times that you need the breakers to pop more quickly, so the 20 Ampers in your TIU do not blow.  The problem with all these breakers are that the quality control on most breakers is not always exacting.   Although the Scott 10 Ampers are pretty darn sensetive, other manufactures 15's are not quite so exacting unfortunately.  This is the reason I use the Scott type 10 Amp resettable breakers, with them I have never damaged any part of my layout.

 

PCRR/Dave

 

 

Thanks,   pack of 10's it is

 

Terry

I just blew the same fuse again - and I can't blame the kids his time!  (By the way - there WAS adult supervision.  You try watching active twins at every second when they are at two opposite ends of a 33 foot layout with a stairway closet in the middle blocking your view. ha!).  So here's what I did - I wired a reversing loop to the same terminal strip to which the rest of that main line is wired.  Red wire from center rail to red post on 24 post MTH terminal Strip.  And black wire from outer rail to black post on MTH terminal strip. Tripped the PH and blew the same fuse.  I know reversing loops on two rail set ups require special considerations but thought on three rail I could just wire like I would any other power drop?  Neither book above comments on any special wiring considerations for reversing loops. What did I do wrong now?   Peter 

Peter,

thought on three rail I could just wire like I would any other power drop?

You can. You most likely don't have it wired the way you believe that you have it wired.

PJB,

   Please understand I meant not disrespect about the parental control, twins run in our family also, I fully understand active twin boys and what takes place in actuality.  Give anything in the world, to be in your shoes, however.  My boys play with their trains in heaven with their Grandpa & the Supreme Architect I am sure.

Your reverse loop problem sounds like you have one of the red mid rail wires misplace on to an outside rail at a connection point some place, look it over closely, other wise you must have a shorted track in your layout.

Barry - Thanks for being gracious.  I realize that what you say must be the case. But I checked. Maybe I'm subliminally overlooking it.... Will look again. 

Peter,

 

Do as Dave suggests. Carefully trace all wires from the TIU output back to the tracks, looking for a reversed wire pair or an inadvertent short circuit.

 

You could try disconnecting one wire at a time until you find the culprit.

Disconnect the output to the channel that the fuse is blowing on and power up the TIU channel, if it shorts the TVS is shorted in the TIU for that channel.  G

Great advice from PCRR/Dave.  Mistakes made are very instructional.  The ability to make these mistakes in a safe protected environment is incredibly valuable.

    Nope just a little more parent supervision required, let the kids develope their engineering skills thru quality play time, with the train layout!  The world needs more chief engineers, especially today, legos don't make it happen.  The price for a Chief Engineer starts with layout damage thru experience.  Never knew a NASA chief engineer who did not start his education at a very young age, building O guage train layouts.  Every single one as a child started his education in this manner.  O Gauge trains are more than just a hobby, an engineering learning experience like no other.

Burn the Legos at age 10.

Great advice from PCRR/Dave.  Mistakes made are very instructional.  The ability to make these mistakes in a safe protected environment is incredibly valuable.  Pat B.