TIU Meltdown. Gee is the G dead?

Scott, I have two original issue Rev G's.  One I keep to use on my workbench or to pop onto the layout when the Rev L is acting up (with no difference in performance, incidentally).  The other is running my grandson's layout.  Both were repaired when new, and both have run flawlessly since.   So I am a Rev G fan.  But at this age, I would be loath to invest money into repairs.

One suggestion I would make:  check all 4 channels to make sure that some eager beaver hasn't turned off the DCS signals.

No one else has used the system. I don't even know how to turn of the DCS signal. Even if someone did wouldn't the factory reset fix that?

Scott Smith

I don't know.  Might I suggest that you contact GGG and ask his advice.  George will give you honest recommendations, and is not out to bleed you for repairs.  And he know his stuff.

The fact that it got so warm that it appeared to warp, is a big clue here. Someone has to go inside and see why.

The warmth makes me wonder if there was a loose connection on an inside terminal to the banana jacks.

Though the fact that it only got warm after an 8 hour session is curious (assuming since you did not state it was warm on the future 2 sessions that it was at normal temperature).

-Dave

rev g terminals are soldered; no nuts

Scott,

That was a long run time. Those 4 engines and smoke units may have had the output limit right up close to the amperage limit of a TIU channel. I think I would remove the bottom and take a photo, close enough for detail, that looks like the photo in the manual of the first troubleshooting page.(attached)

There are cooked components. Slow cooked.

email the photo to GGG and gunrunnerjohn.

There doesn’t seem to be anything  obvious.

hey Scott,

I zoomed to the terminals near the light. The red wire on the terminal has a shaky looking solder joint. Then, where the wire travels over the heat sink it looks like it may have melted from being too close or touching the heat sink. (See the red arrows) 

Check that wire - it may be that there was enough heat from the heat sink to melt through the wire. or the shaky solder joint on the terminal created heat with the amps for 8 hours.

Good catch, Carl.

Scott, The Rev G has a common trace for all the "grounds", not 4 discrete channels like all the others. Did you have only one ground connected on each side of the TUI? If you did, that is likely the issue. The ground trace is too light for the amperage of 4 channels going through 1 connector. The cure is to tie all the grounds together and spread out the current density over the trace. Or, by-pass it all together and tie all 8 black terminals together with a heavy gauge wire. No fuses to worry about with the Rev G, just be sure the wire is heavy enough. BTDT.

Chris

LVHR

What channel or (s) were in use at the time?  Sounds like you lost the DCS Signal.  Not sure why from a over heating situation.  It may be repairable again.  G

Each channel is using an individual z1000 brick. I have used barrel adapters on each.

Scott Smith

I am using a channel for each track. I have 4 tracks.

Scott Smith

I guess if your pulling near max on all channels it may get warm, still not sure what caused loss of DCS.  Besides the factory reset, I would go into the menu an turn on DCS on all channels AON.  G

Single DC motor, smoke unit and 2 incandescent bulbs per car. I would guess at least 3 amps per train. 2 trains per track and you are getting close to maxing the Z-1000's. The TIU should have handled it easily.

Thanks for video. Very nice display!

How did that suspect wire look? Any sheath melt through near the heat sink?

Next time, use fuse wires that connect from the track to the output of the TIU. When a short happens, the short will respond to the fuse and not the TIU itself. Just replace the fuse inside the wire when this happens.

No fuses in the Rev G TIU.  The traces are the fuses.

gunrunnerjohn posted:

The traces are the fuses.

That's what makes them fun!

use fuse wires that connect from the track to the output of the TIU.

That would be incorrect. The fuses would not protect the TIU.

Fuses should always be placed in the hot wire between the transformer and the TIU channel input.

Everything that you need to know about DCS is all in MTH’s “The DCS Companion 3rd Edition!" This book is available from many fine OGR advertisers and forum sponsors, or as an eBook or a printed book at MTH's web store!

Everything that you need to know about DCS WiFi is all in MTH’s “The DCS WiFi Companion 2nd Edition!" This book is available from many fine OGR advertisers and forum sponsors, as an eBook or a printed book at MTH's web store!

Moonman posted:

Single DC motor, smoke unit and 2 incandescent bulbs per car. I would guess at least 3 amps per train. 2 trains per track and you are getting close to maxing the Z-1000's. The TIU should have handled it easily.

Thanks for video. Very nice display!

How did that suspect wire look? Any sheath melt through near the heat sink?

No problem with the wire or sheath melt. It's going back to MTH for repair.

Scott Smith

Some failures of the G version can't be fixed.  If you look at the bottom of the board and see an internal trace that's cooked, MTH will tell you it's not repairable.

John,  It still works in conventional, so no trace damage.  Just got real warm.  His issue is loss of DCS signal on all channels I believe.

As far as fuses: placement is based on what your trying to protect.  If we make the assumption that most failures and causes of overload occur on the track or engine on the track (5V Boards).  Then a fuse between the TIU and track will pop first and unload the TIU and down stream transformer.

If some how the TIU is the cause of a high current short, you are not protecting the TIU, but hopefully the transformer protection activates.

Internal fuses in TIU (other than first generation G model) are 20 amps and protect TIU traces.  Most if not all transformers are UL maxing out at 10amps.  So, personally, I like the Fuse between the TIU and the track (where most shorts come from).  G

One wonders what failed to make it overheat...

GGG posted:

John,  It still works in conventional, so no trace damage.  Just got real warm.  His issue is loss of DCS signal on all channels I believe.

As far as fuses: placement is based on what your trying to protect.  If we make the assumption that most failures and causes of overload occur on the track or engine on the track (5V Boards).  Then a fuse between the TIU and track will pop first and unload the TIU and down stream transformer.

If some how the TIU is the cause of a high current short, you are not protecting the TIU, but hopefully the transformer protection activates.

Internal fuses in TIU (other than first generation G model) are 20 amps and protect TIU traces.  Most if not all transformers are UL maxing out at 10amps.  So, personally, I like the Fuse between the TIU and the track (where most shorts come from).  G

I dislike changing the topic to another as it seems to happen in my posts a lot.  But please indulge me this one time but it is sort of on topic though: GGG are you then saying that a fuse on BOTH sides of the TIU would be best???  I always have done what Barry posted above and never put fuses on the outgoing side of the TIU.  Easy enough to do though.  But I have an "I" version I think and that has fuses so would I be wasting my time?

thanks - walt

GGG, to add to WALT'S question, is it also degrading, to the DCS signal, to have such a deformity (fuse holder and fuse) in the wire going to the tracks from the TIU?

great followup question Dave. Thanks

- walt

I am not recommending anything, just pointing out strategy of protection.  No a fuse does not effect the DCS Signal.  It is just a burnable wire.  In reality no matter where the fuse is, if the short occurs down stream it will see the overload and open.  Placing it before the TIU protects Track and TIU from a short, at the rating of the Fuse.  G