I run all 4 outputs fixed.
Gregg posted:gunrunnerjohn posted:I have never seen this request before, and I don't even know how you modify the TIU for full voltage all the time from the variable channels. I've never really wanted to do this, so it's never come up.
I must be lost on this one.... All our 8 var channels are set to FXD mode. When the layout is power up from wall switches all of the 8 ZWs come to life along with every tiu channel.. 16 of them... Single track layout. no loops. No conventional. Don't have to touch the remote.
Someone mentioned a hardware modification to the TIU to insure the variable channels stayed in fixed mode, even if you select the track and vary the voltage. If you read the quote below, maybe my comment will make more sense. I have no idea how they accomplish this, but it it sounds like they actually modified the hardware. See the quote below.
L & N posted:DJ's Trains posted:I would just put up with having to cycle the power to the TIU myself.
I was really surprised at how often we had to do that. Some of our members would unnecessarily power down the entire layout when they just needed to cycle TIU power. We even have a toggle switch for just that. At least for our group it was worth doing. We even had an MTH authorized tech make the conversion.
Steve
gunrunnerjohn posted:I have never seen this request before, and I don't even know how you modify the TIU for full voltage all the time from the variable channels. I've never really wanted to do this, so it's never come up.
This is a requirement insisted upon by a couple of individuals in my club (San Diego 3 Railers), who maintain the wiring on the layout. I can't find any information about this either. That's why I'm asking. I can imagine one would wire a jumper around the component that varies the voltage in the channel on the TIU's mainboard , but this sounds useless if you only run fixed voltage brick transformers on DCS to begin with. The only thing I can figure is that their current configuration allows use of either power bricks or a Z4K transformer to run DCS. And to make it more idiot proof, they hard-wired the variable voltage channel to fixed so that changing the voltage on the Z4K won't change the operational mode of the variable channel.
Actually, the more I'm reading up on this, and the answers I'm getting here, make me think this "requirement" just a lame excuse for not doing anything, like replacing a 13 year old TIU that's probably malfunctioning. 
Ok thanks.. Makes more sense now . Perhaps in a large club setting to keep unwanted changes??
Gregg posted:Ok thanks.. Makes more sense now . Perhaps in a large club setting to keep unwanted changes??
That's the only reason I can come up with. But why not just have the Z4K transformers connected directly to the track and the power bricks connected to DCS? Sounds like less trouble to me. 
L & N posted:DJ's Trains posted:I would just put up with having to cycle the power to the TIU myself.
I was really surprised at how often we had to do that. Some of our members would unnecessarily power down the entire layout when they just needed to cycle TIU power. We even have a toggle switch for just that. At least for our group it was worth doing. We even had an MTH authorized tech make the conversion.
Steve
Steve, Out of curiosity, where did your tech find out how to do that conversion?
And, how did the tech get the information on exactly what to mod?
I have done this mod for the NJ High Railers. It is not hard to do, your just jumpering around the FETs. You loose Emergency stop features for those var channels, but otherwise it just prevents inadvertent shutdown or cases where a FET goes bad. G
George, I was wondering about the exact details, are you saying you just basically short out the FET stage?
DJ,
I run all 4 channels fixed, it gives me all the different DCS options for running all the time. Including conventional engines from the hand held remote control.
PCRR/Dave
Dave, you're missing the point, the conversation is about modifying the TIU so the variable channels CAN'T vary. In other words, make them into permanent fixed voltage channels.
At this point I'm only using three outputs, the one variable output is fixed as conventional is extinct on my layout and I don't miss post war stuff at all.
gunrunnerjohn posted:George, I was wondering about the exact details, are you saying you just basically short out the FET stage?
Yes, Thanks for asking, that's the information missing here. The details of the modification would be appreciated.
DJ's Trains posted:Steve, Out of curiosity, where did your tech find out how to do that conversion?
Don,
George (GGG) did the modifications, being that he is a factory trained tech I didn't ask. One could infer that he learned this in class or has enough knowledge of the circuitry to have figured it out on his own.
Steve
I'm sure I could figure it out, but it's a whole lot easier to find out how a successful mod was done. 
I never removed the cover on one of the modified TIUs to look at what was changed.
Steve
