Fitting Decoders to the Bachmann class 66
Ian Birchenough
capacitors that have to come off?
--
Ian Birchenough
Andy Sollis- Churnet Valley model Railway Dept.
DCC, but do make sure it runs OK under DCC before you clip it.
I have had the mis-fortune of having a duff motor in a class 24, and because
it is still under warranty, Bachmann wish me to send it back.... I'm not so
sure as I have removed the capacitor, which I guess will either invalidate
the warranty, or mean at the least if it is faulty, be charged for any
repair or replacements!
Andy
"Ian Birchenough" <i...@nospam.demon.co.uk> wrote in message
news:CqUDfoHT...@birchenough.demon.co.uk...
John Turner
"Ian Birchenough" wrote
> Anyone had problems with the Bachmann 66 once chipped? Are there any
> capacitors that have to come off?
It's just plug & play (at least with a Gold decoder) but I snipped the
capacitors to be on the same side.
Finest running large diesel model I've come across once Gold chipped.
John
Chris
fitting a DCC module. The capacitor is a 'spark quench' for the old DC
system and all DCC mobile modules have one incorporated in the circuit so it
would be duplication. Capacitors in parallel, which it would be if left in
situ, their values are additive. The greater capacitance could affect the
DCC signal to the encoder.
Just zis Guy, you know?
<pUEpe.117977$g12.1...@fe3.news.blueyonder.co.uk> was posted by
"Chris" <c.wa...@blueyonder.co.uk>, including some, all or none of
the following:
I forgot to do that (or rather, didn't know not to - RTFM!) the first
time. The first decoder was somewhat - ahem - degraded as a result.
Guy
--
http://www.chapmancentral.co.uk
"To every complex problem there is a solution which is
simple, neat and wrong" - HL Mencken
goo...@sheerstock.fsnet.co.uk
Encoder?
Any capacitors across a motor are isolated from the DCC signal on the
track by the decoder circuitry and have no effect on the DCC signal. It
has nothing to do with adding to any suppression built into the
decoder.
The motor output of the decoder is pulse width modulated (PWM)
effectively an AC signal (but not the same as the DCC signal) and this
is why suppression components (capacitors and inductors) affect the
running of locos. They present a varying impedance to the decoder
depending upon the PWM frequency (which can be varied in some decoders)
and the capacitance or inductance value.
Suppression components designed for DC use are exactly the opposite to
what we want for DCC, which uses an AC drive to the motor. Inductors
block AC and an inductor in series with the motor (in DC designed to
prevent interference getting back to the track) will attenuate the
motor drive. Capacitors block DC but conduct AC and a capacitor across
the motor (in DC designed to suppress interference as noted by Chris)
will shunt some of the motor drive away from the motor. The
characteristics of the motor also come into play due to the series and
parallel combination of the motor and suppression components.
Unless you analyse the circuitry of each individual decoder (accounting
for all possible PWM frewuencies), suppression and motor combination it
is very difficult to predict what the results will be. This is why some
people report good results leaving suppression components in place. The
best policy is to always remove the suppression components.
Andrew
John Turner
<goo...@sheerstock.fsnet.co.uk> wrote
> Suppression components designed for DC use are exactly the opposite to
> what we want for DCC, which uses an AC drive to the motor.
I may be misunderstanding what you're trying to say, but surely with DCC
although the track voltage is AC the drive to the motor is rectified by the
decoder and as a consequence is DC not AC.
John.
Chris
is wrong. An AC voltage or current has a positive and negative component
hence the name alternating whereas PWM is pulsed DC i.e short pulses width
give a slow motor speed and long pulse width give a faster motor speed till
eventually the motor could - note could - be fully turned on. I am using
Lenz, Digitrax, NCE decoders and you know what they say "if all else fails
read the instructions" and without fail they all say make sure the motor
brushes are totally isolated and any capacitors are removed. I'm a bit long
in the tooth and the only system I can remember that insisted that a spark
quench condenser oops! capacitor be installed and they provided one if one
wasn't fitted was Hornby's Zero 1. their rational behind this was a spark
contains all the odd harmonics to infinity and hence RFI would cause
problems but you all know that anyway :-).
goo...@sheerstock.fsnet.co.uk
Sorry, I must have had a brainstorm. The motor drive is pulsed DC and
not AC.
I'll get my coat...
Andrew
Keith Norgrove
Yes, but apart from the misuse of the term AC the rest of your
argument is sound, the inductance and capacitance effects you describe
are equally valid for DC pulses as its the rate of change of current
that matters.
Keith
Make friends in the hobby.
Visit <http://www.grovenor.dsl.pipex.com/>
Garratt photos for the big steam lovers.
Chris
pulsed DC or not. A discharged capacitor will allow current to flow whilst
charging and will be deemed fully charged when 5xCxR (5CR's) has elapsed
when it blocks DC till it is discharged when the cycle repeats itself. I
believe SCR's (Silicon Control Rectumfriers oops Rectifiers) rectify the AC
from the track and the control part of the SCR is pulsed to apply pulsed DC
to the motor. I also understand that Hornby are developing a DCC system. Has
anyone any idea if it is NMRA compatible?
Keith Norgrove
wrote:
> I also understand that Hornby are developing a DCC system. Has
>anyone any idea if it is NMRA compatible?
>
If Hornby try to push a non-nmra system they will be wasting a lot of
effort and money! Fleischmann and others have tried this and have had
to give in and change to nmra standard.
Only Maerklin have been able to do their own thing, and that only
because their 3-rail AC system gives them a huge captive customer
base.
John Turner
"Keith Norgrove" wrote
> If Hornby try to push a non-nmra system they will be wasting a lot of
> effort and money!
I think they'll be wasting time and effort anyway, but I can understand why
they will want to go along this route. Equally so I think Hornby believe
they can do no wrong, so whatever system they come up with, NMRA compliant
or not, they'll just go their own sweet way.
I think there's already enough choice in the DCC field, and unless someone
is able to produce a high quality, high specification, NMRA compliant system
at a significantly lower price than is currently available then I see little
point.
John.
goo...@sheerstock.fsnet.co.uk
Chris wrote:
> This could go on and on so this is my final gripe. A Capacitor is a DC block
> pulsed DC or not. A discharged capacitor will allow current to flow whilst
> charging and will be deemed fully charged when 5xCxR (5CR's) has elapsed
> when it blocks DC till it is discharged when the cycle repeats itself. I
> believe SCR's (Silicon Control Rectumfriers oops Rectifiers) rectify the AC
> from the track and the control part of the SCR is pulsed to apply pulsed DC
> to the motor.
The DCC signal is rectified with a bridge rectifier to provide DC
traction power. This is regulated to a lower voltage to power the
microcontroller that generates the PWM signals based on the incoming
commands. The motor drive is a MOSFET H bridge. I'd be confident to
assert that this is true for at least 99% of all commercially available
decoders.
What you describe sounds more like a DIY system once produced by
Maplin, 20 years ago, and maybe Zero-1 but I don't know about that.
Andrew
Andy Sollis- Churnet Valley model Railway Dept.
"John Turner" <nos...@nospam.invalid> wrote
I think they'll be wasting time and effort anyway, but I can understand why
they will want to go along this route. Equally so I think Hornby believe
they can do no wrong, so whatever system they come up with, NMRA compliant
or not, they'll just go their own sweet way.
John.
I would be suprised if Hornby were going to all this trouble to now backdate
all their old locos with 8 pin sockets only to go alone with their own
system? They really would be shooting themselves in both feet if it was not
NMRA complient etc or even on a par with the Bachmann Eee Zee system...
Hopefully it will be better - although the recent live steam may serve as an
example and support your theory John... :-(
Andy
John Turner
"Andy Sollis- Churnet Valley model Railway Dept." wrote
> I would be suprised if Hornby were going to all this trouble to now
backdate
> all their old locos with 8 pin sockets only to go alone with their own
> system? They really would be shooting themselves in both feet if it was
not
> NMRA complient etc or even on a par with the Bachmann Eee Zee system...
> Hopefully it will be better - although the recent live steam may serve as
an
> example and support your theory John... :-(
I'd say that the Bachmann system is probably NMRA compliant, but not
necessarily NMRA compatible. Gulp, now explain what you mean.
Basically the Bachmann system is produced by Lenz, but because Bachmann are
going along this route in a fairly half-hearted manner (they seem unwilling,
for instance to produce DCC equipped locos without capacitors) that they are
trying to modify their system to cope.
The latest 36-550 decoders (Lenz LE1014 in a bigger box) are no longer
default configured in the same way as the standard Lenz chips. Consequently
you can't just bang one in a conventional Bachmann DCC-ready loco and expect
it to work properly with any other DCC command centre (including those made
by Lenz). I believe they've disabled the silent drive, changed some
performance curves, and certainly adjusted starting voltage and acceleration
and deceleration delay. A big mistake in my opinion.
What's betting that Hornby won't so something similar?
John.
Andy Sollis- Churnet Valley model Railway Dept.
"John Turner" <nos...@nospam.invalid> wrote
The latest 36-550 decoders (Lenz LE1014 in a bigger box)
<snipped>
A big mistake in my opinion.
What's betting that Hornby won't so something similar?
John.
Apologies for how I have snipped the post, I'm not trying to twist what you
wrote, I can assure you !
Frankly, I don't see why either firm needs to bugger about with a third
parties decoder when they are good enough off the shelf in the first
place... To be honest, I was thinking along the lines of a Controller only
anyway, still using the excellent range of chips like Lenz or TCS... So why
should they need to deviate away and make something up? But , like you say,
I bet they will...
I think (not discounting a controller) that their time and money would be
better spent on R & D for sound or lights (in the locos not currently
fitted, that can be done at an acceptable mass produced product (maybe with
the ability to change\add further sounds?) to keep the cost down for the
people who may not want it....
Andy
Ian Birchenough
<nos...@nospam.invalid> writes
<snip Andy>
>
>I'd say that the Bachmann system is probably NMRA compliant, but not
>necessarily NMRA compatible. Gulp, now explain what you mean.
>
>Basically the Bachmann system is produced by Lenz, but because Bachmann are
>going along this route in a fairly half-hearted manner (they seem unwilling,
>for instance to produce DCC equipped locos without capacitors) that they are
>trying to modify their system to cope.
>
>The latest 36-550 decoders (Lenz LE1014 in a bigger box) are no longer
>default configured in the same way as the standard Lenz chips. Consequently
>you can't just bang one in a conventional Bachmann DCC-ready loco and expect
>it to work properly with any other DCC command centre (including those made
>by Lenz). I believe they've disabled the silent drive, changed some
>performance curves, and certainly adjusted starting voltage and acceleration
>and deceleration delay. A big mistake in my opinion.
resetting them so they work as any normal compatible decoder?
--
Ian Birchenough
John Turner
"Ian Birchenough" wrote
> Ah could this be why my 66's are not happy? Is there a method of
> resetting them so they work as any normal compatible decoder?
Not that I've found. Previous batches could be reset by writing '33' to
CV8, but it appears that they have different default settings to previous
batches.
My recommendation would be to try a Lenz Gold decoder in your 66 - that way
you'll see just how well your loco is capable of running, and then having
proved the point get the Bachmann decoder back to your supplier and ask for
a refund.
Bachmann have not made any announcement about the apparant changes in
default settings, but if you compare the instruction sheet which accompanied
the decoder and compare it with those of a standard Lenz LE1014 you'll see
the differences. In my opinion these changes make the 36-550 not fit for
general DCC use, although they *may be satisfactory* for use with Bachmann's
E-Z Command system/
John.
Mick Bryan
"John Turner" <nos...@nospam.invalid> wrote in message
news:d8c3sr$rcd$1...@newsreaderg1.core.theplanet.net...
> I'd say that the Bachmann system is probably NMRA compliant, but not
> necessarily NMRA compatible. Gulp, now explain what you mean.
>
> Basically the Bachmann system is produced by Lenz, but because Bachmann
are
> going along this route in a fairly half-hearted manner (they seem
unwilling,
> for instance to produce DCC equipped locos without capacitors) that they
are
> trying to modify their system to cope.
>
>
And I believe that Bachmann are also looking at fitting sound chips to the
66's............ £38 is the minimum price I've heard, but Bachmann say that
this would push the RRP of the 66 over the "magical" £100 mark, which
they're not prepared to do. Even though this would obviously be discounted
down by *some* retailers to below £100.
Cheers,
Mick
John Turner
"Mick Bryan" wrote
> And I believe that Bachmann are also looking at fitting sound chips to the
> 66's............ £38 is the minimum price I've heard, but Bachmann say
that
> this would push the RRP of the 66 over the "magical" £100 mark, which
> they're not prepared to do. Even though this would obviously be discounted
> down by *some* retailers to below £100.
If they did it using a top quality chip which would work reliably and give
quality performance with Lenz and other command centres then I believe
they'd be on to a winner, but if their offering meant the thing worked like
a dog (as their existing DCC fitted class 25) then forget it.
John.
Jane Sullivan
<nos...@nospam.invalid> writes
>
I'd have thought the obvious thing to do was to make up a small batch of
200-500 or so and offer them for sale at one of the main exhibitions,
such as Warley. They could also donate some to the appropriate layouts
at the show on the condition that they run them so the public can see
and hear how they operate.
--
Jane
OO in the garden http://www.yddraiggoch.demon.co.uk/railway/railway.html
John Turner
"Jane Sullivan" wrote
> I'd have thought the obvious thing to do was to make up a small batch of
> 200-500 or so and offer them for sale at one of the main exhibitions,
> such as Warley. They could also donate some to the appropriate layouts
> at the show on the condition that they run them so the public can see
> and hear how they operate.
This would be an expensive way of marketing the thing. The sound chip would
only be viable if produced by the multi-thousand.
John.
kim
news:d8d73g$ktr$1...@newsg4.svr.pol.co.uk...
> And I believe that Bachmann are also looking at fitting sound chips to the
> 66's............ £38 is the minimum price I've heard, but Bachmann say
> that
> this would push the RRP of the 66 over the "magical" £100 mark, which
> they're not prepared to do. Even though this would obviously be discounted
> down by *some* retailers to below £100.
South West Digital is working on its own sound chip for the UK66 and I don't
expect to see any change out of £110.
(kim)
John Turner
"kim" wrote
> South West Digital is working on its own sound chip for the UK66 and I
don't
> expect to see any change out of £110.
Me neither, and you won't until the Chinese get involved with their
manufacture and start churning them out by the tens of thousand.
I suspect South West Digital turn their decoders out by the tens (or may
hundreds) but until the price drops significantly that same price will stop
very many enthusiasts from buying.
John.
kim
news:gf3qe.21342$bl3....@fe1.news.blueyonder.co.uk...
> This could go on and on so this is my final gripe. A Capacitor is a DC
> block pulsed DC or not.
Only when fitted in series. When fitted in parallel - as in most models - it
acts as an AC attenuator affecting higher frequencies more than lower ones.
The exact reverse is true of RF chokes.
(kim)
kim
>I would advise the removal of any capacitor and inductor where fitted, when
>fitting a DCC module.
In case anyone with limited electrical knowledge is tempted to try this I
should warn them that removing the inductors (or "RF chokes" as I prefer to
call them) will also remove the power supply to the motor. The supply path
has to be made good again by fitting new wires which is not always
straightforward where printed circuit boards are involved.
(kim)
Chris
Kim's comments has to be addressed. The whole point of removing the C's &
L's is to isolate the motor when fitting a decoder. I would not suggest
removing any RFI components if the loco was to be used on a DC system, they
are there for a purpose! The power for the motor is fed, in total isolation,
through the orange and grey wires from the decoder. As to the point of
"anyone with limited knowledge etc" someone with limited knowledge should
seek guidance on how to proceed before attempting to fit a decoder. Some
models are easy to do whilst others can be an absolute 'pig'. One in
particular comes to mind is the China made R369A BR 3 Car DMU 110. A
ringfield motor is used on this model but on first glance one wonders how
the power is fed to the motor as there is only one wire to one of the
brushes. It turns out that the left hand, the one without any wires to it,
brush is fed via the long self tapping screw picking up the right hand rail
power through the body of the motor. To successfully isolate this brush the
long screw must be discarded, the self tapping hole re-tapped to 6BA and a
non conductive 6BA bolt - I used a nylon one - used to hold in place the
brush spring cover. The orange wire can now be connected to the brush
terminal. I will now get off my soap box and go and hide in the corner :-).
Chris
John Turner
"Chris" wrote
As to the point of
> "anyone with limited knowledge etc" someone with limited knowledge should
> seek guidance on how to proceed before attempting to fit a decoder. Some
> models are easy to do whilst others can be an absolute 'pig'. One in
> particular comes to mind is the China made R369A BR 3 Car DMU 110. A
> ringfield motor is used on this model but on first glance one wonders how
> the power is fed to the motor as there is only one wire to one of the
> brushes. It turns out that the left hand, the one without any wires to it,
> brush is fed via the long self tapping screw picking up the right hand
rail
> power through the body of the motor. To successfully isolate this brush
the
> long screw must be discarded, the self tapping hole re-tapped to 6BA and a
> non conductive 6BA bolt - I used a nylon one - used to hold in place the
> brush spring cover. The orange wire can now be connected to the brush
> terminal. I will now get off my soap box and go and hide in the corner
:-).
Just a further comment on this, all of which is quite correct for that
particular era of Hornby Ringfield powered units (locos or dmus) but it is
no longer the case with current (Chinese) production models in which both
brushes are now electrically isolated from the motor chassis and pick-ups.
Consequently the process identified by Chris is no longer required on
*current* models.
John.