[Richard Johnson]

QUOTE (Keith Underwood @ 8 Jun 2008, 23:41) <{POST_SNAPBACK}>Hi everyone
Has anyone had any problems with Bachmann Deltics or Bachmann A1's (both of the 8-pin socket type). Both my locos were running fine but suddenly they do not respond on the track. They are fitted with TCS MC2 decoders (my system is Gaugemaster Prodigy Advance).
I have tried putting them on the program track and reading back the address, which is fine on both. I have put the "blanking plug" back in and run them on a DC test track, which is fine (nice runners in fact). The wheels and track are clean and all other DCC locos are running OK. I have even tried swapping for a couple of spare decoders (Lenz and Bachmann) and, while they still accept programming on the program track and read back their correct addresses, they do not respond on the main track!
I could try hard-wiring the decoders in and by-pass the socket, but I don't know if this will solve the problem, whatever it is!
Any ideas? Or has anyone had a similar thing happen and resolved it?
Thanks
Keith

Hello Keith

To reconfirm:
* these two loco's only will not run, all others are fine.
* both loco's will accept programming track instruction with no problem but will not run on the main track.
* decoder reset tried, after which both loco's re-programmed OK but still will not run on the main track.
* alternative decoders tried, both loco's still OK on programming track but still will not run on the main track.
* Both loco's tried on normal DC, seem to run OK.

The fact that all decoders are OK and will programme OK too would indicate that the problem is between the output side of the decoders and the motors - check the following remote possibilities:

reinstall and programme the decoder, test with controller connected to a separate bit of track - not the layout.

reinstall and programme the decoder, test on another layout with another control system.

put one probe of a meter on orange wires socket position - touch both motor brushes to check for continuity - repeat with Gray wires socket position.

Do any of the pins on the 8 pin plug go very close to the chassis when pushed fully home in the socket. If so when the body is on any added pressure can create a short across pins.

do either of the brush to wire contact points sit very close to metal - ditto

is there any solder bridging between pins on the bachmann sockets, or perhaps a super small strand of copper between the pins of the sockets... this is not uncommon

are the pins loose in the sockets, so one isn't making god contact - unlikely but it can happen: to test, very slightly bend the pins connected to orange and gray and re-insert the decoder in socket...

Check motor impedance. If its less than say 30 ohms its very low and motor may be going bad - this happenned a LOT with bachmann motors at the time of the A1 release as they were badly assembled with the bearings not properly seated.

You could also check motor after a few minutes running on DC with a load on it - if its getting warm, its in need of replacement.

Personally at this point, if nothing obvious pops up then my next step would be to disassemble the loco just in case something obvious is missed, reassemble carefully, test on DC then bypass the socket and hard wire the decoder.

Sorry I cannot be more specific.

Regards
Richard
DCCconcepts

 

[Richard Johnson]

QUOTE (Keith Underwood @ 10 Jun 2008, 19:40) <{POST_SNAPBACK}>Just an update if anyone is still following this story. I had one last attempt with the Deltic last night - put a Bachmann 36-553 decoder in - coded and confirmed as "21", put it on the main track and it ran perfectly! So I went to bed happy. However, when trying it again this morning, no response again! I then did a factory reset (CV8 - value 08) which set the decoder back to "3", put it on the main track and it ran again on code "3". Switched the system off, came back to it later, tried to run on "3" again - no response! So, I now have an intermittent fault. All other DCC locos are still working fine and the Deltic still runs beautifully when converted back to DC. I have tried everything on Richard's list, taken out the "hidden" capacitors suggested by John, and have now basically run out of ideas. As my locos still perform faultlessly on DC, I am now considering reverting to DC like in the "good old days". It's a shame as I still think DCC has advantages over DC, but I have lost "trust" in the whole thing and would feel happier with the old conventional system. What price "progess" eh!!!!!

***Sorry that its still not solved... but I think Ian (wiggy) has some intersting comments in his last post!

We've covered every possible thing that may relate to the obvious, so we need to look elesewhere for an answer.

I've been thinking it through and its quite illogical that two loco's both have failures, and equally illogical that given the variety of decoders tried and the symptoms you've seen that its anything at all to do with locos or decoders at all really.

There only remains trackwork wiring and controller, and its rare for track wiring to create such an issue....

So...

I think you should first try Ians idea of removing all other locos and testing them

and...

Then try running them by connecting the controller to a simple separated test track.

Then...

If the problem goes away on a separate bit of track we need to talk about your layout wiring and configuration

But....

If its not then perfect on a separated bit of track, we do need to try another controller. I have a sneaky feeling that this may end up being a control system that is close to failure or marginal on performance spec... I'm talking individual controller here, not the brand.

So - try either another of the same brand or another brand.... or both.

Either way, stick with DCC - DCC is usually a very low problem technology and very tolerant, and I do feel you've simply hit a worst possible issue early on, and once its fixed, it'll be plain sailing for the rest of your miodelling wit DCC!

Richard
DCCconcepts

 

[Richard Johnson]

QUOTE (railstimulator @ 11 Jun 2008, 17:36) <{POST_SNAPBACK}>My system is prodigy with their decoders fitted to my Hornby Mallard A4 & my Hornby Cardigan Castle.. The mallard has always operated correctly but the Castle was a bag of bones on DCC from day one. The faults included

Trapped on manufacture the leads from pick up to DCC socket. OK on DC but flakey on DCC.
None running with DCC chip with body in place OK without.
Would run some mornings but noit afternoon

All these wre fixed by replacing the pickup to socket leads and routing away from lead weight and sharpe edges.
Replaced wires from the socket to the motor.
Finally found that the -ve wire from the decoder back to the DCC plug was held in by the insulation and the conductor was thus intermittent. resoldered now OK.

Have also another question about the Castle tender, no one on the Hornby site has replied maybe someone here will.
The tender has a set of copper brushes that would appear to be for making contact with the wheels on one side. However on mine they don't. These brushes are part of a larger copper plate that terminates in a small slot in the front of the tender where the loco draw bar is inserted, The drawbar has a lower copper p[artt that touches the contacts and the disassembly notes go to length to ensure that you put this back together correctly so the copper parts mate. However the drawbar copper is isolated from the main loco wheels and the body. Anyone know if this is to allow more pick up area?
the A4 hasa wired drawbar.

***Re the castle. they are indeed supposed to be pickups. I wonder if they simply decided not to worry about it on assembly as pickups on just on one set of wheels its such a half-baked approach!

I am just installing a decoder in a similar castle and on this one too they also fail to contact the wheels properly....the easy way is to adjust so they do so and then make sure the power transfers OK to the drawbar. You can then connect the drawbar power to the appropriate side of the loco for pickup.

If you want to really improve running also add a little weight to the tender to improve contact with the rails and then and add new pickups using phosphor bronze wire soldered to a little copperclad, and permanently couple & hard wire the tender to the locomotive... adding "both side" tender pickup to loco pickup will really help performance.

Richard
DCCconcepts

 

[Richard Johnson]

QUOTE (Keith Underwood @ 12 Jun 2008, 17:29) <{POST_SNAPBACK}>Thanks, Upnick. Funnily enough, I was wondering why they had "upgraded" the spec, especially as the advert says it has extra functions - presumeably for "sound fitted" locos, etc. I do not have any sound enabled DCC locos, but the articles I've read seem to indicate that the Version 1 of the Prodigy Advance already has all the functions required anyway!
I have had my Gaugemaster for over 2 years and was tempted by the new "wires free" Bachmann Dynamis. I know that (currently) it does not support a programming track but the rest sounds pretty good so I have "taken the plunge" and ordered one. For one thing, if my locos work OK with it when I get it, it will confirm that the Gaugemaster unit is definately at fault and I'll get on to them to see what they can do.
I'll keep you posted.
Keith

*** The REAL reason for the prodigy squared upgrade is actually nothing to do with "US locos" at all! The Gaugemaster answer is factually inaccurate. the "Prodigy advance squared" upgrade is so it does not directy conflict with permitted use of some NMRA standards, and really MUST be done if you want a truly DCC compatible system.

Sure, the functions were there in name in the original software but they totally misused the permitted CV allocations and this meant that the original gaugemaster and MRC software would ONLY access those functions with MRC's own awful sound decoders!

NMRA insisted that they stop using CV numbers they were not entitiled to use as it severely compromised global standards, and so they did the revision to fix this and a few other quirky minor things in the original software.

Once that revision is done, its actually an OK control system at the original MRC Pricing, but I feel its a little exxy at Gaugemaster prices.

Regards

Richard
DCCconcepts