Insulating Hornby Decoders

[robcat]

I have just fitted a Hornby R8249 decoder to a new DCC ready  Hornby 61xx Prairie tank loco.

Easy to do but the decoder instructions say do not tape round the decoder as it needs air space around to keep cool or it will overheat. Whereas the instruction sheet in the locomotive box says use the supplied black protector sleeve which fully enveops the decoder (to stop damage  and electrical shorts).

This seems contradictory.  What is the correct way please?

Also has anyone had trouble with older hornby decoders (hard wired from factory) not working properly? I had no problem with my Hornby Select but the locos don't respond very well to my new NCE PowerPro.  There is no problem with the new Prairie tank above on NCE so I think it must be the older decoders.

[mjb1961]

Hi robcat,,,use the insulation sleeve ,they are big though,I cut it in half ,then fit the decoder inside and then trim off any excess ,then I use a bit of tape to hold it in place ,leaving the two ends open so to allow heat to escape ,,,,I don't know about the older decoders but I'm sure someone else will ,,,,,,,,mjb

[96RAF]

If you lose or dont have the insulating sleeve then buy some heat shrink tube from the likes of Maplin, just dont shrink it.

I shrink the ends a little bit just to stop the decoder slipping out But leaving an opening for air circulation.

 

The old Hornby R8215 decoders were unreliable and prone to losing their address and/or suffer runaway, whereas the R8249 is much better. Unfortunately Hornby appeared to be using up old stock in their DCC fitted locos so there are still lots about. If you do get problems then the only answer is to replace them with later decoders.

[RDS]

I do the same as RAF96, although with such a short length of Heat Shrink it is difficult to prevent the middle shrinking and I have had no problems even when it appears to have shrunk fully.  

 

One thing I would avoid though is the type of Heatshrink Tubing that has an adhesive layer inside.

[robcat]

Thanks for that everybody, I will use the sleeve.

Another point is : should I remove the capacitor from the factory fitted DCC hard wired locos and / or the DCC ready loco to improve the performance or is that only when converting an analogue loco?

If I do remove the capacitor(s) do I just leave the cut ends of the wires which linked them to the motor open or do they have to be connected to anything?

thanks 

[Rog RJ]

You can remove the capacitors if you want to.  Personally, I've never removed any capacitors when using Hornby decoders and never had any trouble.  Modern decoders from other manufacturers also seem to be largely unaffected by the capacitors nowadays but there are always exceptions to the  rule.   Just cut the wires as short as possible if you do remove them.

 

I don't normally use the insulating sleeve as it's quite bulky but when I do, I just shrink the corners as other members have said.  What I normally do is put insulation over any exposed metal that the decoder could come into contact with to prevent accidental shorts from happening.

 

 

[poliss]

I use Kapton Tape to insulate my decoders.

The capacitors are only there to prevent the motor from interfering with TV and radio signals. They serve no other purpose and don't need to be connected to anything.

Modern decoders have their own TV suppression components.

[81F]

 I have to admit I usually wrap mine in insulating tape (do I hear screams!) and even did onein masking ape and so far hve only had one burn out and that was one with hardly any wrapping!

 

Having said that I do not run my locos for very long and if left in a siding there is a good chance it's one of my "Dead" ones (ie not connected to the bus but fed through the point in the traditional manor.

[96RAF]

Its a matter of two things:

 

1. Heat, even if fully wrapped so long as your decoder isnt working its socks off then it should be OK.

2. Insulation, the glue on some tapes or sleeves may reduce the isulation across components and cause a short. Or just degrade the components.

 

Neither can be good for long term reliability.

[robcat]

 Thanks all

I have fitted the decoder with the sleeve but I might try using a small plastic channel section moulding which I can glue the ends of the webs to the inside of the cab roof (plenty of room in the Prairie Tank) leaving an open ended slot,   !-----!   shaped, which the decoder can slide into. That gives insulation and air flow.