Strange MS480 behaviour.

[peterm1]

I damaged this decoder and sent it to Zimo for repair. It came back with a 6 pin plug on it. I tested it on my MXTAPS and it worked OK. I de-soldered the wires I didn't need, leaving the red, black, orange,grey and speaker wires. I also soldered Lais stay alive wires to the positive and ground pads. Not the capacitor pads. I found a 6 pin socket and soldered the pickup and motor wires to it and all the rest connected directly from the decoder as above. I used a very fine stranded wire 36awg I think to go from motor and pick ups to the speaker, decoder and stay alive in a wagon and made sure that none were pinched or shorted. This loco is a Dapol B4, so hardly any room inside.

 

Now for the problem: This loco runs superbly... when it runs, but it seems to have a mind of it's own. I can use it and then go and do something else. Come back to it in a few hours or next day and nothing. I get Lenz error, 2 no connection on the programming track. Come back again and away it goes with perfect sound and running. I've stripped it down and checked the wiring with a multi meter and found no damaged wires or dodgy joints. I've run out of ideas and hope someone can come up with something.

[WIMorrison]

I would start fault finding by removing the 'extra' items you added, such as the LAIS unit. and see if that removal resolves the issue you see.

[peterm1]

Thanks.

I'd thought I might do that but I'm tending towards a fault in the decoder. I will try cutting out the stay alive though.

[WIMorrison]

I have fitted goodness know how many Zimo decoders over many years and any running issues have always been found to be with the 'extras', e.g. lights, wiring, pickups, etc never with the decoder (probably true of all the other decoders also.)

[peterm1]

Now that I've finished the Dapol D class I can get on to this B4 again. I'll let you know how I go.

[Izzy]

Although not common I have had problems with both Zimo sound & non-sound decoders on occasion. A batch of half a dozen MX600’s which were faulty in one way or another sticks in my mind, so it’s not unknown for them to be at fault. 
 

Bob