Do diodes leak voltage .....DC shuttle line with a DCC loco..weird happenings

GAP said:
Valves real transistors with heaters ;) ;) ;)
Click to expand...

I recall using an old (even in those days) valve powered analogue computer at college!

Back on topic, for future reference was the chip set to reverse direction to compensate for the reversed motor wiring or did the loco travel in reverse to LGB direction on analogue?
Apologies if this has already been explained, but I'd like confirmation.
 
Hi Neil
In the end I set the CV to make the loco to go in reverse.
So it is now opposite to all of my other locos (LGB, Bachmann etc)

BUT....at least it now works on the DC shuttle very well and was shuttling back and forth yesterday afternoon for three hours as we ran some live steam on the main line and battery on the local line.

Being me, I can not leave well alone,.........the DC shuttle will soon have the option of being a DCC shuttle in the near future (using the Tam Valley shuttle with a DCC booster).

There will be a multiswitch to choose the DC or DCC wiring option (needed for knocking out the diodes and connecting the extra feeds from the TAm Valley unit, when operating as a DCC shuttle).
 
MMMM.......... treading gently on thin ice, as this is in he DCC section :o :o :o :o :o

But there's a lot to be said for gold ole auntielog:

one black wire

one red wire

O0 O0 O0 O0 O0 O0 O0 O0 O0 O0 O0 O0 O0
 
GAP said:
Valves real transistors with heaters ;) ;) ;)
Click to expand...

Care to help sat here with avo valve tester going through bucket of 4cx250b's I aquired
 
This is a Bachmann loco, right? Does it have a polarity switch? Many of them have one (behind smokebox door?), to switch between NMRA and "other large scale" polarity, ie. LGB. This switch might have been left active even if it's now decoder fitted.
 
ntpntpntp said:
This is a Bachmann loco, right? Does it have a polarity switch? Many of them have one (behind smokebox door?), to switch between NMRA and "other large scale" polarity, ie. LGB. This switch might have been left active even if it's now decoder fitted.
Click to expand...

No Nick it was a newly DCC-ed LGB 0-4-0 switcher which had all of the problems on the DC shuttle line. The DCC Bachmann Climax was being used as a comparison.
All the problems were with the polarity from the decoder in the 0-4-0....once that was sorted everything is fine.....
Yes I have quite a few bachmann locos and know about the polarity switches behind the smokebox doors.......
 
Doh - really must pay more attention in class :-[
 
Rhinochugger said:
MMMM.......... treading gently on thin ice, as this is in he DCC section :o :o :o :o :o

But there's a lot to be said for gold ole auntielog:

one black wire

one red wire

O0 O0 O0 O0 O0 O0 O0 O0 O0 O0 O0 O0 O0
Click to expand...

Yes, but if you want to do more then go one way then the other, with more than one engine, then there are LOTS of black and red wires..
EVERYWHERE!!
:o ;) ;) ;)
 
beavercreek said:
Now I suspect that there are a few fellows who will be able to unravel this little mystery.

I have one of my sections of the layout (the quarry line) as a plain DC shuttle that spirals from one end to the other and back etc with a diode gap at either end for stopping the loco.
It has been working absolutely fine with DC locos and can handle up to 8amps.
So far so good.....

My other layout sections are powered by DCC unit, or DC, depending on what I want to run.

I have just DCC-ed an LGB 0-4-0 D&RGW diesel switcher with a ESU Loksound XL 3.5 board, sound etc (and enabled DC analogue usage in the CVs).
Tested it on the DCC section and everything is tickety-bo...motion, sound, lights, functions etc

As it was one of the locos that usually domiciled on the quarry (DC analogue shuttle line), I then brought it to that line and tested it with straight DC power but strange things .....no sound (I have sorted the sound prob!)........
there is normal motion and lights.....BUT it does not stop after the diode gaps like it did before the installation of the DCC decoder, it just wants to keep on going after the diode gap.

The DC power is from a Train Engineer with PWC switched off ( I tried it 'on' just to see what may happen....confuse the decoder etc... but no difference).
There is up to 22v and plenty of amperage on tap.
I then put a DC analogue loco (same type of loco) onto the quarry line, to see if the diodes had gone west since a few days ago when they were last used.....and the analogue loco stopped happily after the diodes at each end and then reversed after the set time.
So it is definitely something that the decoder on the 0-4-0 is exhibiting whilst crossing the diode gap...

Now I maybe wrong, (more than likely), but I suspect that the decoder is being able to use any 'leakage' of voltage that the diode may allow to power the motor and lights even when it has gone past the diode gap.
If I am correct ....are there diodes with the power and voltage handling, that do not exhibit any leakage?... Schottky type?.......the ones that I have used for years on the DC shuttle are plain old IN4001......

Or do decoders just not work with a diode set-up as found in DC shuttles....

A quandary.... or can I not see the wood for the trees....
Click to expand...

we had a similar problem to this and the fix was changing the motors cvs setup in the decoder
can exactly remember which ones but it was for the motor and it solved the problem
you may email me at don@computer cables.co.nz and I can try and find the cv which it maybe
 
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