New-style Hornby DCC Blanking Plug

[RFS]

I got my Hornby S15 today and fitted a Lenz Standard+ DCC decoder in the tender. Normally Hornby locos have the capacitor in the tender wiring, but there's no sign of one in the S15. I usually snip these out when they're visible. I've not removed the loco body to see if one's there, but I would only do that if there's a problem.  So far all is well.  

 

But then I noticed the blanking plug was different: it appears to have two components added to the circuitry, both stamped F7.  So my first thought was, are these some form of capacitor, which means removing the plug and replacing with a decoder automatically removes caps?

 

Here's a picture

 

[mezzoman253]

I got my Hornby S15 today and fitted a Lenz Standard+ DCC decoder in the tender. Normally Hornby locos have the capacitor in the tender wiring, but there's no sign of one in the S15. I usually snip these out when they're visible. I've not removed the loco body to see if one's there, but I would only do that if there's a problem.  So far all is well.  

 

But then I noticed the blanking plug was different: it appears to have two components added to the circuitry, both stamped F7.  So my first thought was, are these some form of capacitor, which means removing the plug and replacing with a decoder automatically removes caps?

 

Here's a picture

 

If they are cap's, that's a very elegant solution to the problem of removing them.

 

Rob  

[Tony_S]

I think they are diodes.

[tractor_37260]

I think they are diodes.

 

I'd agree, The diodes are fitted so any lights (if fitted) will work on DC  Bachmann use a similar arrangement on their blanking plugs, for locos with cab lights on function 3 

[Dagworth]

Look like diodes to me, I have seen Hornby blanking plugs with capacitors fitted, I mentioned it in an age-old capacitor thread here at the time

 

Andi

[Tony_S]

Also Googling SMD F7 reveals mainly diodes (assorted!) not resistors, capacitors or inductors.

[RFS]

I've already posted this in my thread specifically with the S15, but as it's of more general interest (and may affect more new engines) I'll repeat it here.  Seems Hornby have moved to providing interference suppression by changes both to the DCC socket and the blanking plug. Hence it's going to be more difficult to remove the caps if you need to.

 

Here's their reply below.  Incidentally, anyone know what it takes to remove that C1 cap?

 

S15 suppression components.

 

Other locos have motor suppression components  fitted external to the socket/plug within the actual wiring. Therefore it is easy to remove any component.

 

The S15 blanking plug does indeed carry some of the suppression components.. but note, the actual 8 pin socket board is also fitted with suppression parts. The capacitor (C1) in the bottom right of the picture below is connected directly across the motor of the loco. It is usually this capacitor that users will remove from their locos.

 

 

 

Hornby decoders work Ok with the suppression components in place, some other manufacturers decoders do not… it is common for users to remove the motor capacitor.

 

Removing C1 may well resolve the issue for some users.. but this may affect the warranty of the product.

 

[Grovenor]

Here's their reply below.  Incidentally, anyone know what it takes to remove that C1 cap?

A soldering iron and a pair of tweezers. Wield the iron so it heats both ends together, then remove with the tweezers.

Regards