Short circuit help! - Will a Frog juicer help?

[JohnR]

Can someone help with a short circuit problem I've got?

 

I have just upgraded to an NCE Power Cab (from a Bachman Dynamis), thought I dont think that is the cause of this short circuit. It seems to occur whenever a loco approaches a point, or when the point is thrown in that direction. Yet I cannot find any problem with the wiring - and of course, this was working fine previously. 

 

I think the head has melted a few brain cells, so would appreciate some suggestions?

[Michael Hodgson]

You can presumably confirm it's not the new command station by reverting temporarily to the old one  - or even to DC?

My money is on you having disturbed something inadvertently when you changed over, creating a short, a stray wire or piece of metal somewhere.  If you've been looking at too long, you won't see the obvious.  Come back to it with fresh eyes tomorrow.

[RFS]

Anything to do perhaps with the current hot weather? Has an isolating joint closed up due to expansion? Just had a problem with that in my converted loft, where the two rails either side of the lift-up flap were now just touching and hence marking their blocks occupied to the detectors. I was surprised as the rails themselves are soldered to copper-clad sleepers. So bit of careful filing needed to correct.

Edited July 18, 2021 by RFS

[Ray H]

Check your track power connection on the back of the PCP (panel) to make sure you haven't got a stray piece of wire touching where it shouldn't be.

 

Can you isolate parts of the layout so that you don't waste time searching parts of the railway that work OK?

[meil]

19 hours ago, JohnR said:

Can someone help with a short circuit problem I've got?

 

I have just upgraded to an NCE Power Cab (from a Bachman Dynamis), thought I dont think that is the cause of this short circuit. It seems to occur whenever a loco approaches a point, or when the point is thrown in that direction. Yet I cannot find any problem with the wiring - and of course, this was working fine previously. 

 

I think the head has melted a few brain cells, so would appreciate some suggestions?

How are you switching your frogs? if it's by frogjuicer then your new DCC is more sensitive than your old one.

[GoingUnderground]

1 hour ago, meil said:

How are you switching your frogs? if it's by frogjuicer then your new DCC is more sensitive than your old one.

I think that unlikely. Dynamis, like the ESU ECoS and CabControl, and the old ESU Navigator, are at the "more sensitive" end of the spectrum.

 

The NCE PowerCab, the OP's new system, seems to be more tolerant of transient shorts than Dynamis judging by past posts here on RMWeb.

Edited July 19, 2021 by GoingUnderground

[JohnR]

Thanks all for the suggestions. I've tried the Dynamis on the layout, and get the same short at the same point. 

 

My conclusion is that the frog is not switching, ie the switch on the PM1 motor is not working somehow.  After all the problems I had getting the PM1 to work in the first place, I'm disappointed that I face the prospect of having to go through all that again. 

 

I only have a vague understanding of a frog juicer etc - would adding one of these cure the problem? If so, how do I install it etc? 

[Ron Ron Ron]

30 minutes ago, JohnR said:

……My conclusion is that the frog is not switching, ie the switch on the PM1 motor is not working somehow.  After all the problems I had getting the PM1 to work in the first place, I'm disappointed that I face the prospect of having to go through all that again. 

 

I only have a vague understanding of a frog juicer etc - would adding one of these cure the problem? If so, how do I install it etc? 

Seep motors are notorious for their switch failing to work properly.

It’s a choice between a Frog juicer, or a better point motor with a more reliable built-in switch.

 

Frog juicers are easy to install.

It’s the same wiring as for most switches.

3 wires.
One to each rail and the third to the isolated frog.

 

 

.

[JohnR]

6 minutes ago, Ron Ron Ron said:

Seep motors are notorious for their switch failing to work properly.

It’s a choice between a Frog juicer, or a better point motor with a more reliable built-in switch.

 

Frog juicers are easy to install.

It’s the same wiring as for most switches.

3 wires.
One to each rail and the third to the isolated frog.

 

 

.

 

Fantastic Ron - any recommendations?

 

[ISW]

1 hour ago, JohnR said:

Thanks all for the suggestions. I've tried the Dynamis on the layout, and get the same short at the same point. 

 

My conclusion is that the frog is not switching, ie the switch on the PM1 motor is not working somehow.  After all the problems I had getting the PM1 to work in the first place, I'm disappointed that I face the prospect of having to go through all that again. 

 

I only have a vague understanding of a frog juicer etc - would adding one of these cure the problem? If so, how do I install it etc? 

John,

 

Have you considered simply adding a cheap microswitch, mechanically operated by the throw of the turnout switches, to set the polarity of the frog? That way you can 'dispense' with the switch in the Seep.

 

Ian

[Oldddudders]

Like Hoover is to vacuum cleaners, so Frog Juicer, a registered brand name, has become a generic. I have been very happy with the Gaugemaster equivalent, even though it uses a relay, which is inherently slower than the solid state device in the original Tam Valley Frog Juicer. My DCC system is Digitrax.

[melmerby]

5 minutes ago, ISW said:

John,

 

Have you considered simply adding a cheap microswitch, mechanically operated by the throw of the turnout switches, to set the polarity of the frog? That way you can 'dispense' with the switch in the Seep.

 

Ian

I'd agree with that.

I had a lot of Seep point motors at one time (all long gone now) and I fitted microswitches to them all.

 

[roundhouse]

I have a lot of SEEP solenoids. They are cheap, easy to get hold of when replacements are required and fit easily under my 2 x 1 inch framed boards,  hence why I use them despite the switch issue. On most of my layouts i have now converted to Tam Valley Frog Juicers and in some cases the easier to obtain and more affordable Gaugemaster ones. The Gaugemaster ones seem to work fine on my HO layout and and also on a few recently added turnouts in my modern image N scale fiddleyard. However when I tried them on my new 009 layout they didn't work properly with the shorter wheelbase 009 locos, so they have been swapped with Tam Valley Frog Juicers on my HO Czech layout.

 

Neither types will work on DC so if you do plan to switch between DCC and DC then best to use another method.

 

Before going down that route do check that all rolling stock is on the track and not straddling a turnout switched against them. With my layouts being portable, I also disconnect the jumpers form all boards then reconnect one at a time till I find the area with the short.

Edited July 20, 2021 by roundhouse

[Michael Hodgson]

Seep point motors are fine for throwing the point. 

 

The usual problem with the switch is that the wiper arm just fails to make contact, or repeated use can even cause the contact to wear out.  The effect of this ought to be that the frog is dead, so the loco should judder to a stop on the frog.  That would also suggest your pickups may not be the greatest either.  But it's a lousy mechanical design and can fail in other ways, and the effect can (unusually) be a dead short such that the point is electrically opposite to the switch.

 

I would disconnect it and substitute a better switch, as suggested by ISW or if it is easier by other means such as a relay. 

[Free At Last]

I added extra switching to Seeps to interlock a 3-way point.

[JohnR]

A Gaugemaster DCC80 has been ordered. I thought it was worth trying for the cost.

[KingEdwardII]

3 hours ago, JohnR said:

any recommendations?

MTB MP1 - slow action and with an utterly reliable built-in switch for frog polarity. I have 30+ of them and I've never yet had a problem.

 

Mike.

[JohnR]

52 minutes ago, KingEdwardII said:

MTB MP1 - slow action and with an utterly reliable built-in switch for frog polarity. I have 30+ of them and I've never yet had a problem.

 

Mike.

 

I'm sorry, I was asking for recommendations on a frog juicer, not a replacement point motor.

[SamThomas]

On 20/07/2021 at 13:20, JohnR said:

 

I'm sorry, I was asking for recommendations on a frog juicer, not a replacement point motor.

RMW can be like MacDonalds sometimes - you order one thing & get something else.

Edited July 21, 2021 by SamThomas

[TWG]

On 20/07/2021 at 13:20, JohnR said:

 

I'm sorry, I was asking for recommendations on a frog juicer, not a replacement point motor.

 

The post to which this was a response said "It's a choice between a frog juicer or a better point motor with a more reliable switch...".  This could be construed as applying to the alternative when you asked for "any suggestions".  So perhaps King Edward viewed it in this light.  In my opinion it is a good suggestion.  SEEPs are crude devices which I see as a relic of the past.  Some people think that frog juicers are in principle not a good idea.  If you search RMWeb you will find previous discussions on the matter.

[JohnR]

I made a video about this - problem solved!