Should you remove the TV suppression capacitor?

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bulleidboy
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Should you remove the TV suppression capacitor?

#1

Post by bulleidboy » Sat Mar 28, 2020 10:07 am

Should you remove this - Yes or No. Having had a problem with a certain decoder, I was looking at the Bromsgrove Decoder site. One of there guides is for the Hornby Merchant Navy Class (a favourite of mine). It is a pre-DCC loco and it says, during the installation, you must remove the capacitor. Now I am aware that some later models do not have these fitted, but older ones certainly do. Also some models appear to run normally/well with the capacitor left in place. Also the Bromsgrove site gives CV setting for the M/N Class. Do you do this automatically when fitting a decoder? Barry
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Re: Should you remove the TV suppression capacitor?

#2

Post by brian1951 » Sat Mar 28, 2020 10:10 am

Yes BB remove it, serves no purpose.

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Re: Should you remove the TV suppression capacitor?

#3

Post by Brian » Sat Mar 28, 2020 10:22 am

A difficult to answer topic
Leave 'em in or whip 'em out? That is the question. :?:

Removing all the capacitors and there are frequently more than one, will never do any harm for the DCC user.
It wont do anything to alter running for the DC user either, other than possibly seriously upset your family or neighbours while running locos. :o
The capacitors are fitted to try and remove as much as possible the radiated interference produced by the arcing of the motor brushes, on DC this is (if no suppression capacitors are fitted) transmitted into the nice long aerial (antenna) you have called "the rails" and sent out into the wide world as interference in the radio spectrum. Poor quality TV down leads and some radios can be seriously effected by the inference.
However on DCC there is more in the way between rails and motor. The decoder and its electronics.
It may be noticeable in the way Bemf is read by the decoder, causing poor general running.

Personally and what I do is to leave them in and run the loco on DCC. If is performs correctly then dont worry. But if it performs poorly remove them all. But if you want to get them out from the onset there is no reason not to do so, ;)
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Re: Should you remove the TV suppression capacitor?

#4

Post by bulleidboy » Sat Mar 28, 2020 10:58 am

Thanks Brian(s) - I'll get snipping on one particular loco and see if it improves - I'll also look at the CV's. Barry/BB
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Re: Should you remove the TV suppression capacitor?

#5

Post by Mike Parkes » Sat Mar 28, 2020 11:51 am

Have noted on some Bachmann models which have a number attached to the motor they act to retain the motor from physically turning within the body. Also on the Hornby Sentinels the capacitor is buried under the motor meaning a complete strip down of the model is necessary to remove it.

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Re: Should you remove the TV suppression capacitor?

#6

Post by Stese » Sun Apr 19, 2020 9:21 pm

@Brian, given the digital switchover, is the RF produced by locos till a cause for concern?
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Re: Should you remove the TV suppression capacitor?

#7

Post by Brian » Sun Apr 19, 2020 10:34 pm

Stese wrote:
Sun Apr 19, 2020 9:21 pm
@Brian, given the digital switchover, is the RF produced by locos till a cause for concern?
Yes it can be, especially if areral downleads are not upgraded.
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Re: Should you remove the TV suppression capacitor?

#8

Post by RFS » Sun Apr 19, 2020 10:47 pm

I've had problems with decoders in Hornby locos which are fortunately fairly easy to remove. In particular I've had issues with models where the decoder was not causing a problem with the loco itself, but was causing other locos to play up when it was moving.

For example, I bought 2 Hornby 2-BILs when they first came out. Each one performed perfectly on its own. But put the two units into a consist and it was a serious case of kangaroo petrol. Separating the two units and putting them on adjacent tracks whilst still in consist quickly identified which one was causing the problem. But removing its capacitor didn't fix the problem. Only removing the cap from the other did. Same with a pair of Hornby class 73s which I had had for several years and never before run in consist. When I did - same problem.

Likewise a problem with a Bachmann 2-EPB. Once a Hornby M7 on an adjacent track was actually moving, the 2-EPB simply would not move. Until, that is, the M7 came to a stand. Again. removing the cap from the M7 (and all other Hornby locos) resolved the issue.

The Bachmann 2-EPB, like all their EMUs, have 3 caps buried in the motor housing. I have removed them from two units but it requires the entire motor coach and motor assembly to be dismantled and re-assembled. Took about an hour each, but I gave up on my others as in the end no performance issues were occurring with them.
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