Magic Lightbulb

It should be 18 volts. Base and socket type are not important.

 

This and a whole lot more is all in MTH’s “The DCS O Gauge Companion 2nd Edition", available for purchase as an eBook or a printed book at MTH's web store!

Why are they called magic lightbulbs?

Because they have magic inside.  

 

Barry, I thought 24V had more magic inside?  G

What kind of magic?

Good magic. G

George,

I thought 24V had more magic inside? 

No, that's not the case.

 

Some time ago, OGR sold a 24 volt bulb as an intended "magic light bulb" (I really hate that phrase!). However, when I spoke with OGR some time later, they said that they really didn't help nearly as much as an 18 volt bulb and that they were better as power indicator lights, for which I use them.

 

I have them wired in parallel with the power going into my TIU channels so I can see at a glance which TIU channels have power.

I am the person who discovered the light bulb fix about a year before DCS was released.  At that time I was given the job to learn the system and get it to operate on a buss wired layout.  A lot of experimenting was done with different voltage bulbs and the 18 volt bulb proved to be the best.  To this day, many years later, I still have a 10 signal on every section of track and hundreds of feet of live catenary.   Down the road we now have the rev L TIU and that does not need light bulbs.  I am a huge fan of the rev L TIU.

So far so good with the Rev. L TIU, but your stablemates at NJ-HR might disagree with too much admiration of the Rev. L.  

 

I never heard if they sorted out why it was eating variable channels...

 

True John.  You have been there and know that not many layouts are that big.   I will talk to you about it when I see you on Staten Island.

 I have a chart of the bulbs somewhere on my old computer. It was further discussed that some guys weren't having as great of success with the bulbs. Some had determined that bulbs needed to draw over something like .1 amp to be effective. I maybe off on that number but there is a threshold.

 Susan Deat's filter actually works just like a bulb but doesn't waste any amps from your source going to track signal correction.

 I remember reading about Marty's findings and then further by the guy who worked on Tony Lash's layout who's name escapes me right now. (Jamie?)

 I had discussed this with MTH techs directly who at first dismissed the findings. They then went on to grumble something like just get any bulb. I found that annoying as I believed people (Marty and others) that they worked.

 Now all this is usually not needed with the newest version "L" Tiu. I tested so extensively back then, because I run two rail and G scale. I had much more difficulty at first obtaining good signal. The best advice I got from a MTH factory tech was to break the loop of track in one place to prevent the signal from doubling back on itself. I followed that theory with the use of block wiring in all future wiring. It sounds outdated and too much work. It is actually very simple to do.

 I can post the old chart of bulb numbers and results with each when I find it. I believe the problem with a higher voltage bulb, is that it's not burning at full brightness and there was attenuating type properties of the bulb over it's operating range?? or something like that.

 I'm not an electrical guru and forget all the terms exactly.

 A lot of credit should go to these original owner/ developers who charted new terf tuning the system.

 This is just one small reason, out of the hundreds that I respect Marty's and Barry's opinions so heavily. I have pretty much proved that what they say works! It used to be tuff to remember all the facts learned until our Barry put it all in a concise book to use as a reference.

 PS. I still laugh to this day of memorable posts of 2 pictures that showed 1 of an onion, and 1 of Uncle Fester, fixing DCS signal!

Do the bulbs that are built into the RealTrax power lock ons act in the same way as magic bulbs mentioned in this thread? I have a rev I3, or rev13, TIU and both variables channels suddenly died on me but the fixed channels are working OK. I was getting 6-8 signal on my older 4'x8' layout which will be 4'x16' soon, do I need any specific bulbs to increase the signal to 9's and 10's?

 I am not sure what bulb is in the MTH realtrax lock-on. I would hope that it would help at the least. If your not getting optimal signal, you could try certain 18v bulbs that draw more current. I would go with whatever number Barry recommends, with older TIUs.

 Anyone in just about any situation with an older TIU, could try Susan's filters as well. I got good signal using them, in most situations. I do remember in one, that a bulb worked better. 

 I run my G gauge DC at higher voltages using an old TIU (25 volts).

I get better signal across the board, using the L, without any need for filtering.

thx Joe!