DCS Passive mode and multiple blocks

If you run a feed from a single TIU output to each of 4 blocks, you will in effect connect the center rails of all 4 blocks together, which will create other problems.  I think you'll have to use 4 TIU channels, with each output feeding a different block.

I have 4 TIU channels, but one blew out due to a short where I had a 10amp circuit breaker that didn't fire before I guess something blew in the TIU. I've never fixed it (and haven't run DCS is years).  But I was thinking maybe to add is passively. 

Thanks

You could leave one block without DCS, to see if you like operating DCS.  You might also call MTH direct to get a price on repairs; depends on what model (vintage) TIU you have whether it's worth repairing.

I'm not familiar with DCC but, if you running DC into the tracks and do not reverse polarity to get reversing, you MIGHT be able to use diodes to prevent one block from backfeeding another, and run two blocks from the same TIU output.  I don't know what diodes would do to a DCS signal.

Its probably a gen1 TIU.  I bought it when they first came out.

If you had a single transformer for the layout, you could arrange it, but to do as you suggest would put 4 300-watt transformers in parallel (assuming they are phased--if not, you'll be melting wires), which can be dangerous.

The only advantage to passive mode is the ability to push more than 10 amps to the track.  There were reports of signal degradation just by using passive mode

Ben,

There were reports of signal degradation just by using passive mode

I've never actually seen a documented case where this was true, however, I expect that it's possible.

Did you open the TIU ? it's probably only a fuse burn, very easy to replace 

He said it's one of the first generation TIUs.  They didn't have fuses.  For several years, MTH was beefing them up at no charge.

I believe I opened it up when it blew and saw no fuse.  I should have sent it back to MTH then.  If I get serious about DCS, I'll probably by a new rev-L version.

thanks everyone!

Heck in large scale we've successfully signaled 1,400' of track using 1 channel in passive mode with DC power.

Barry

I never used passive and have no experience with it firsthand.  That is what I heard and took in the notes at the DCS user group meeting

I don't know how the posts got mixed up, ands have me saying that I blew a channel.  Twern't me who said that.

Ben,

What I stated at the meeting when this discussion came up was what I have stated above. That is, that I've never seen first-hand any case where passive mode has resulted in a lowered DCS signal strength, although I wouldn't rule it out as a  possibility.