No, but it’s great to know the fuse is not blown. I will start over with new channels, and double check my wiring. Thank you...
I only really follow in the fall through Christmas as my tree layout is the only space I currently have to set up trains.
So it looks like while I was in "hibernation" this opportunity came and went. Although the modest permanent layout I have planned eventually would likely not need this, I would have ordered one just to have.
So here's to hoping there may be a "second run" of this gadget at some point in the future. I'm not the sort to get a kit and create it from that, so I'll have to wait for now.
Ok, as suggested by friends, take the Legacy System away from the layout for simple/specific testing, TaDa, it works....Then I added the Cab 1 to the Legacy System, they both work, tada. So, now that I know my command control works, I will check out the power on the layout....Now, Progress is being made.. So, I am using a ZW w/TPC’s 2 only 400’s each with 180 watt bricks.
Ok, now, my system is up again, tada, reprogrammed the 2, ZW-C transformers, the TPC’s, everything seems to be working, Cab 1- Cab 2.... Tomorrow, after a thorough check out of all the wiring, I will install the DM TM Buffer....It just takes one step at a time, says my friend at the Madisonville Shops, to Win the race. If I were to give this problem a Reason to go down, “the cause of the shut down”, probably a derailment occurred somewhere on the layout......Happy Railroading...
Hard to say what happened, I'm glad to hear all your components appear to be working. 
John, back on 9/10 I posted some info about the Legacy signal issue I was having on my 2 rail layout. I now have it fixed so I thought I would share the cause of the problem. You were correct it had to be some kind of ground loop issue. First just for info but not related to the problem, the layout power is supplied from a dedicated 20A circuit from the main panel. The house has 2 sub panels, one for inside circuits and one for exterior loads. The balance of the outlets and lights in the train room are supplied from the interior sub panel.
The layout was built with metal foil tape under all the track. All the foil tape is connected together and wired back to the main control cart with a single ground wire. The problem was this wire was connected to a ground pin in a power strip rather than to the proper Legacy base connection. There are 3 power strips on the control cart, power strip "A" plugs into the 20A outlet, "B" plugs into "A" and "C" plugs into "B". The 990 base is plugged into power strip "C", The new Buffer is plugged into "A" and the separate ground pin mentioned above was plugged into "B".
As soon as I unplugged the separate ground connection the buffer indicator turned steady green, the layout works perfectly with all engines working everywhere on the layout. I will ultimately connect the ground wire correctly but I need to disassemble some cable bundles on the control cart to do that. I like it when a fix is that simple. I am really surprised a professional layout builder made this kind of incorrect wiring connection for a Legacy system. Also, none of the unique 2 rail controllers have any effect on the system function.
I see the foil as the problem. If you had just used a wire for an additional antenna to transmit the TMCC signal, there would not be such a large capacitive load from the ground wire antenna to the base (connected to the rails) end of the signal. I think terms like "ground plane", etc. are unfortunate in that they give a wrong impression of the purpose of the antenna wire in the house wiring or as an added antenna wire on parts of the layout that may be shielded from the house wiring. The term ground loop does not apply either. It's simply too much capacitive loading I think.
Chuck is probably right. The buffer will drive quite a bit of capacitance, but there is a limit.
gunrunnerjohn posted:One thing I might suggest it to "tone down" the buffer output somewhat, while still keeping a lot of the benefit of it being used. Here's a simple way to "tune" the buffer output, see if this helps. I'd start with my suggested values, this returns the amplitude of the TMCC signal to near default, but still allows you to have a lower impedance signal to help drive the TMCC problem areas. You can then maybe change the resistors to 150 ohms each to give a small boost if the first one doesn't do enough for the TMCC. The resistors should be 1/2 watt or larger.
Adrian was talking about this, and I figured it would depend on exactly how the DCS was wired. I suspect a perfectly optimum wiring of the DCS might not have the issue, but if you have any signal degradation of the DCS signal, it may be more adversely affected by the boosted TMCC signal. Note that just because you got 10's for the signal test, that doesn't mean you have perfect DCS signal, it just means you have enough for solid communication with the locomotive.
Last time I was in civilization we had a good 10-12V DCS swing everywhere on the layout, but we were somewhere around 1/3 to 2/3 capacitive imbalance inner to outer rails meaning the 450KHz will show up across the DCS differential voltage at 1/3 of the amplitude it has to Earth ground. I may try to hack the driver stage on your buffer to drop the voltage gain while maintaining the low output impedance.
We had an accident on the launch line so we're being encouraged to scrub. I may be back working on this buffer sooner rather than later.
Dropping the voltage gain would be simple, just change the resistor value. If you don't already have them, here's the schematic for the current SMT version of the buffer. The upcoming thru-hole version schematic is identical, the component ID's remained the same.
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Yes, I see a gain of 3.3. I thought maybe a 2K pot in series with the 1K resistor, but it was just a thought when I was looking it over. My layout is not that big and I, so far, mostly like seeing the health of the base when I see the green light.
BTW, that schematic is not clear as the other ones you posted. Just wondering if the res is limited somehow.
This morning I made a temporary connection between the foil tape under the track and the earth ground terminal on the Buffer. The green indicator remained on and got slightly brighter. Completely different behavior than when the foil tape was connected separately to the ground in the house wiring through the power strip. There is some capacitance added with the foil tape under the track but apparently not nearly enough to affect the Buffer. The original problem was caused by the independent connection to the house ground. After I reroute the wiring on the power cart to make this connection to the Buffer Earth ground terminal permanent I will take some new voltage readings.
The connection from the foil tape to the Buffer earth ground terminal is now permanently installed. The voltage readings are 2.7V and 8.05V. The indicator is a bright solid green, all the engines are working as they should. The installation is finally complete.
You have booming signals, shouldn't be an issue now!
The independent connection to earth ground is a big problem, as you likely get ground currents that will cause all sorts of issues.
Not sure if this will help anyone, but figured I should post it. I am running my original TMCC base unit and the Legacy Base. Initially, I always got a bright green light from Day 1. After initially hooking it up, the Legacy worked great, TMCC was not getting commands from the CAB-1...
Wrote to John, he told me to move the TMCC Base Unit further away from the Legacy Base and the Signal Booster, which I did. Voila, everything worked great.
At that point, my Legacy control power transformer was plugged into a 3 prong grounded extension cord which was plugged into the same grounded duplex (2 plug receptacle) that the Large Power Strip with surge protection was plugged into.... The TMCC base unit, ZW-C transformer, other PW ZW and my DC power pack for signal control were all powered through the Power Strip with Surge Protection.
As I am never happy to leave "well enough alone" I decided to get a splitter for the extension cord and plug both my Legacy and TMCC transformer into that grounded extension cord bypassing the power strip.
Ironically, I went down to run trains the other day and my CAB-1 wouldn't work, looked down at the base unit near the floor, and it was not getting any signal from the CAB-1. No red blinking light when you push any command function !!!!
So, it took me a day or two to think about it, (yes I am slow).... and plugged the TMCC base back into the surge protected power strip that everything else is powered from. That was the problem, The CAB-1 and the CAB-2 are both running great !!!
I don't pretend to understand why, but I am glad I am back to having both systems playing nice together in the sandbox !!!
The signal booster is absolutely great, I definitely had some trouble spots and areas where headlights flickered and commands were unreliable, NO MORE ..
Thanks John.... Chris A
chris a posted:Not sure if this will help anyone, but figured I should post it. I am running my original TMCC base unit and the Legacy Base. Initially, I always got a bright green light from Day 1. After initially hooking it up, the Legacy worked great, TMCC was not getting commands from the CAB-1...
Wrote to John, he told me to move the TMCC Base Unit further away from the Legacy Base and the Signal Booster, which I did. Voila, everything worked great.
At that point, my Legacy control power transformer was plugged into a 3 prong grounded extension cord which was plugged into the same grounded duplex (2 plug receptacle) that the Large Power Strip with surge protection was plugged into.... The TMCC base unit, ZW-C transformer, other PW ZW and my DC power pack for signal control were all powered through the Power Strip with Surge Protection.
As I am never happy to leave "well enough alone" I decided to get a splitter for the extension cord and plug both my Legacy and TMCC transformer into that grounded extension cord bypassing the power strip.
Ironically, I went down to run trains the other day and my CAB-1 wouldn't work, looked down at the base unit near the floor, and it was not getting any signal from the CAB-1. No red blinking light when you push any command function !!!!
So, it took me a day or two to think about it, (yes I am slow).... and plugged the TMCC base back into the surge protected power strip that everything else is powered from. That was the problem, The CAB-1 and the CAB-2 are both running great !!!
I don't pretend to understand why, but I am glad I am back to having both systems playing nice together in the sandbox !!!
The signal booster is absolutely great, I definitely had some trouble spots and areas where headlights flickered and commands were unreliable, NO MORE ..
Thanks John.... Chris A
This is kind of the tricky part about the earth referenced signalling. There's more to it than the train layout, the building wiring gets involved too. Our club is a very old WWI fort building and we have about 16V between the 3rd prong of the plug at one end of the building vs the other, which makes a discussion of how legacy propagates get interesting. Especially since we have grounded different parts of the layout with reference to each of them. Also we've seen some of the surge protectors and power strips can do funny transient filtering and raise the impedance the base sees looking into the ground. They are designed to keep 60Hz and block anything else, so sometimes 450KHz has an issue propagating in the return path to the base.
Even if you don't use John's booster for signal strength or drive power characteristics, the other very important thing it provides is a very clear and well defined return path for the layout when the building return path is questionable like ours.
I am waiting for my legacy controller to return from lionel for no signal output. I read the note about the outlet receptacles, I plug in my Cab 1L legacy and no I have a green light an 5.57 volts buffer out to track. The cab1-L ,buffer and wifi controller were all on a regular outlet and all the power bricks were on a ground fault circuit breaker in main house panel. I reversed the plugs and had same no green light. I put both plugs in one outlet an all is well with green light. I also get a stronger buffer out voltage by 0.4 volts with the ground plane not connected to wall outlet ground.
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Also the last three problem engines I have that I thought were antenna and receiver problems now work great.
THANKS AGAIN JOHN Great Buffer
I was about to ask the important question, is the layout working better! 
I see you slipped in that answer. 
I think not trying to have competing earth grounds is generally a better option.
Finally back.
So I had a look on the oscilloscope and basically the output from your booster is providing a good 5-6V to the common mode of our layout but also about 4V in the differential mode so it was really messing up DCS operation. I guess the layout isn't too capacitively balanced.
As a work around, I slipped a 1K trimpot between the base and the booster. End 1 to the base output, End 2 to the ground, and the slider to the booster input (like a volume knob). Then we just turned it down (ignoring the LEDs) until DCS was being decoded well.
When we started we had about 60mV swing on the Legacy carrier in the common mode with the base to the track directly. Now we have about 1.2V swing, so it is helping.
I suspect this will be an easy fix for a lot of people that see the same thing with their DCS on top of legacy, Including the SD3R folks. If you do another batch of PCBs, consider an input trimpot.
I'm done when I get the parts for the kits, so someone else will have to pick up the mantle.
FWIW, this could be done externally without making new boards, just make a little adapter board with a pot on it.
I like a gain adjust better, unless you're saying there is just too much base. But then why would you have a booster. The input is more accessible, I get that.
One thing I really have the booster for is to monitor the health of the base. The green light is so useful for that.
I have a dumb question how do I hook up a oscilloscope to measure the output.
cjack posted:I like a gain adjust better, unless you're saying there is just too much base. But then why would you have a booster. The input is more accessible, I get that.
One thing I really have the booster for is to monitor the health of the base. The green light is so useful for that.
In our layout's case we want more drive impedance, but not more voltage, so we like the buffer output stage, but wanted to turn the gain down.
Jprails posted:I have a dumb question how do I hook up a oscilloscope to measure the output.
Scope probe tip to booster out, ground clip to whatever is in the Earth ground port.
That's a good question. I isolate my scope and measure between the earth ground and base signal. You might do better to measure between the Gnd DC and the Boost DC.
There may be a table somewhere to convert the DC values to the AC signal, I looked but only found
"From GRJ (when he gets a chance probably)...You can also measure a DC voltage that is proportional to the amplitude of the input and output signals on the measurement terminals. In the final documentation I'll have a table that correlates the DC voltage to the p-p voltage of the signals so you can evaluate the signal levels without a 'scope."
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Got my legacy controller back from Lionel today. Had to send it in for a poor output signal, red light. Plugged it in today and got a green light on the booster. I started to test engine response in trouble areas on my layout. I got no flickering lights or stalling, even in yards with many parallel tracks. Engines which I did not run for years, ran like new. Thanks Lionel for repairing legacy units, Dale for the engineering of the booster and John for completing the project.
Marty
Marty, glad to hear about your happy ending!
As for measuring the signal, I just clip the scope probe to the base signal, the boosted signal, and the ground to the earth ground. I use a load of 50 ohms to test the booster's drive capability.
As far as gain control, I believe the best way if I were going to redesign the board would be to actually vary the gain of the output stage. However, just cutting down the base signal with a 1k pot will work almost as well, you still get the low impedance drive of the buffer, and you can do that with the existing buffer design.
GRJ, for the PCB, on the SMD res/caps did you assemble them yourself or have someone do it? If you had an assembly service do them, would you mind sharing who? I'm looking for someone
Some state of the art Chinese assembly house did them. I use PCBWAY for some of my stuff, they did those boards. No way I was going to build 100 or more boards, that was a non-starter!
John, Just got my booster hooked up to the layout, I have been away for a while, so I don't know if this has been brought up before. I have a two rail layout and with the booster hooked up I have both the green LED and the red LED lit. Is this an unusual happening? Tried operating for a short time and things seem ok but I am wondering if this tells of a problem.
Ray
I am glad to see that some one took on the conversion of my original vacuum tube based signal booster and is working out the conversion to solid state. Sorry to hear of dales passing. Hope this project is completed and is a success. My original vacuum tube unit continues to work flawlessly.
Rayin"S" posted:John, Just got my booster hooked up to the layout, I have been away for a while, so I don't know if this has been brought up before. I have a two rail layout and with the booster hooked up I have both the green LED and the red LED lit. Is this an unusual happening? Tried operating for a short time and things seem ok but I am wondering if this tells of a problem.
Ray
Green and red? Are you sure you're not talking about the blue power LED?
What are you using to drive it, the original TMCC command base, or a Legacy command base? The older TMCC command base doesn't put enough signal out to get the green signal indication. If you're using the Legacy command base, it's not putting out a full amplitude signal.
Jim LeFevre posted:I am glad to see that some one took on the conversion of my original vacuum tube based signal booster and is working out the conversion to solid state. Sorry to hear of dales passing. Hope this project is completed and is a success. My original vacuum tube unit continues to work flawlessly.
Jim, Dale was the guy that did the heavy lifting on this one, he had a couple of hand built prototypes and ran around and tested them in a number of locations. PLCProf and I picked up the ball and ran it to the finish line. I was working with Dale up to a few weeks before he died, I was going to turn this into a project we could build. After his passing, it took some time to pick up the pieces and carry on, but it finally did get completed.
John,
I finally ran one of my problem engines Lionel Legacy GS 2 on the Layout and no more problems,
thanks for a job well done for this Layout of 800 ft of track with 096 curves.
Mikey
It's a good design, and it works... but there's one minor point so we all get our "story straight"....
The booster we all have, when turned all the way up delivers about 15V swing into like a 1 ohm real part which is 10W RMS TRP. I'm pretty sure if you hook this up to a 100+ ft layout you're above the part 15 FCC EIRP/TRP limits at this band which is a TRP of 0.1W. However as long as GRJ built them "at home" there's a way out:
Title47 CH 1, SC A Part 15 item 23 Home-built devices.
(a) Equipment authorization is not required for devices that are not marketed, are not constructed from a kit, and are built in quantities of five or less for personal use.
(b) It is recognized that the individual builder of home-built equipment may not possess the means to perform the measurements for determining compliance with the regulations. In this case, the builder is expected to employ "good engineering practices" to meet the specified technical standards to the greatest extent practicable.
Good to know.
Also helpful:
15.13 Incidental radiators.
Manufacturers of these devices shall employ good engineering practices to minimize the risk of harmful interference.
Adrian! posted:It's a good design, and it works... but there's one minor point so we all get our "story straight"....
The booster we all have, when turned all the way up delivers about 15V swing into like a 1 ohm real part which is 10W RMS TRP. I'm pretty sure if you hook this up to a 100+ ft layout you're above the part 15 FCC EIRP/TRP limits at this band which is a TRP of 0.1W. However as long as GRJ built them "at home" there's a way out:
You can get 15V output into a 1 ohm load with the buffer?
gunrunnerjohn posted:Adrian! posted:It's a good design, and it works... but there's one minor point so we all get our "story straight"....
The booster we all have, when turned all the way up delivers about 15V swing into like a 1 ohm real part which is 10W RMS TRP. I'm pretty sure if you hook this up to a 100+ ft layout you're above the part 15 FCC EIRP/TRP limits at this band which is a TRP of 0.1W. However as long as GRJ built them "at home" there's a way out:
You can get 15V output into a 1 ohm load with the buffer?
That's what the load pull gave me. Even a 10th of that would be an issue so I sure hope you built it at home.
Right here in my basement.
The treadmills, switching power supplies, computer USB hookups, and LED light bulbs in my neighborhood are my main sources of ham radio ills. My boosted 455 KHz is about S6 which is well below the usual noise. Just sayin'
