Hornby loco decoder

[geoffb41]

Have two locos which i cant read CV 8 or 1 on

One is a green Charterhouse Southern 903 and the other is a blue city of Bristol 46237

they give a jerk on the program track when i try and read them but can only get XXX

Can't see any R series no.s on either

how can i find out what brand of decoder they are so i can reset and whether they 8 pin or 21 pin etc

[Flashbang]

Hi

Not all decoders can be read! You can write to them ok though.

If you want to reset the decoder back to its default settings including address number to 3 then write to CV8 a value of 8. Occasionally you may have to undertake this more than once! This should reset it. However reference to the locos manual should confirm the reset CV but normally its CV8/8.

As to what number of pins the decoder has, if the leaflet doesn't advise then remove the body or tender (if the decoder is in the tender) and look! You wont see the make usually but the number of pins should be visible.

I would prior to undertaking any decoder alterations, thoroughly clean the programming tracks rails, then clean the locos wheel rims and the inside faces of the wheels where any wheel wipers rub. Also ensure the wipers remain in continual contact with each wheel when the wheel is moved slightly across the loco.

[ColinB]

What controller are you using? I have found that certain controllers don't always read properly. Sometimes you might get better results by trying to read the actual CV. I find with my Elite sometimes it gets it wrong reading say Manufacturers id from the menu, but has better luck reading CV 8 directly.