Chipping An Lgb/aster Ngg13 Garratt

I would still be tempted to try the loco on the track, with the decoders in, and just see if it runs..... even if you can't reprogramme them for some odd reason, they might still be functional.
Of course that would depend on them both still being programmed with the default loco address (3) - though even if they are not, it should still run under analogue.....

DISCLAIMER! I'm no great expert on these things, I only offer advice based on things I've experienced myself or have picked up over the years and believe to be correct - if anyone reading this knows that putting it on the track would be a BAD idea and might cause the escape of Magic Smoke, then please speak up and I will gladly consider myself corrected! ;)

Jon.
 
Jon, just tried it on the track with the decoders and cable fitted but it was dead. Tried various loco addresses just in caser the IDs had been changed. I tried it in analogue with the decoders still in, but again nothing.

Took the decoders out, re-positioned the DIP switches, and all is working again on analogue.

It must be the decoders.
 
Sorry to hear it's still not working; yes, to me that would certainly suggest that both the decoders are faulty, but it was worth a try!
One last test before junking them would be if you have a spare LGB motor block (or indeed any 4-pin power unit), you could plug the decoders on to that one at a time and check them individually - if they still don't work, then I'm afraid I'd consider them dead.
If this is the case and you need to get a replacement decoder setup for your Garratt, then I would strongly recommend a single Massoth XL, which would be easy to fit and would do the job of the two old type decoders. It's not a huge outlay cost-wise, Mark (Muns) at GRO does them for £52, though his website is showing them on back-order right now. That's less than you'd pay for just a single replacement 55021 from LGB.

Jon.
 
He has done that Jon.
 
Yep, you're right Alan - I'd missed that comment, just gone back and found it in post no.35!

Looks almost certain that the decoders are toast then..... :cry:

Jon.
 
Thanks to everyone for their advice and help. I've just ordered a Massoth XL. I'll report back here on how that goes.
 
Good luck, hope it all goes smoothly! Fitting the XL should be quite straightforward, just follow the relevant wiring diagrams in the XL manual to wire the 6-pin cable to it - you'll need to cut the push-on spades off the ribbon cable, as the XL has screw terminals. The XL will come with two sets of the green/yellow/brown/white track/motor wires, you need to pair these up and get the bare wire ends of these pairs into single screw terminals, it can be a little bit of a squeeze to do this but make sure they are firmly held in the terminal as you don't want one coming loose and floating around!
This pic of the XL install in my German Mallet may help, as it's basically the same as what you will be doing. Note that all the connections to the XL are made at just one end of the decoder, you shouldn't need to use any of the screw terminals at the other end which does make things at little easier.

New XL decoder.jpg

Note the paired wires into the track and motor terminals of the XL, and the other ends of these to the two sets of pins on the main board. The DIP switches are set for DCC operation.
This Mallet was purchased second-hand from Germany, and came with a very early factory-installed decoder setup that had just ONE 55020 decoder plus one of the very short-lived (because they were cr*p!) 55030 "booster" decoders - it wasn't working (only one power unit would run) so I chucked the old lash-up and put the single XL in - perfect!


Jon.
 
Jon, many thanks. I actually saw this picture in the thread from 2012 and thought 'that's exactly what I need'.
This is a really great forum.
 
Using the 'one' decoder. you will get better control of the motors. Also something a bit complicated called back EMF ( electro magnetic field) - simply, it keeps you loco running at a constant speed even on sharp corners and up and down hills.
 
stockers said:
Using the 'one' decoder. you will get better control of the motors. Also something a bit complicated called back EMF ( electro magnetic field) - simply, it keeps you loco running at a constant speed even on sharp corners and up and down hills.
Click to expand...

To be pedantic:
Nearly a constant speed..
And, it is Electro-Magnetic Force, or more correctly Back-EMF which is generated in the motor when under load.. This can be detected by the decoder electronics, and used to keep the speed of the loco, nearly, constant as it climbs an incline, or is slowed by the drag of a curve.
</pedant-mode, off>
 
Update. The Massoth XL arrived, was fitted (thanks for the photo Jon) and all is now working as it should.

Thank you all for all the help in getting this engine up and running.
 
Orgiva said:
Update. The Massoth XL arrived, was fitted (thanks for the photo Jon) and all is now working as it should.

Thank you all for all the help in getting this engine up and running.
Click to expand...

That's great to hear, always good when someone has a success story! :)
Happy to have been of some help.

Jon.
 
Actually not pedantic Philip, BEMF is misunderstood by many. The main use of BEMF is to overcome short term irregularities, i.e. binding or sticking... the BEMF value is higher for a moment and the electronics can compensate for the friction by giving a bit more current.

BEMF is normally used this way, to give better/lower starting speeds (where you have static friction progressing to kinetic friction) and smooth out slow speed running. Later people realized by playing with the BEMF parameters, you could exaggerate this function over a longer time, thus the "cruise control" aspect.

Sorry for the derail guys, but this is a very interesting and often misunderstood topic.

Now back to your regularly scheduled programme

Greg
 
Apologies for resurrecting this thread. I have a new problem. The engine works as it should for about 5 - 10 minutes but then just shuts down.

Could the decoder be overheating; does it have a thermal cut out switch? Any other ideas.
 
Sounds like a faulty decoder so soon after fitting?

Not unheard of....
 
I made some measurings with my 20922 (DCC, LV200 booster with 10A, ZIMO MX699KV, smoke unit off, no wagons, no gradient, straight track):

Speed approx. 80% : 0.6 A
Stopping Loco by hand (slipping wheels) : 3.1 A
 
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