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No need for money yet Ron, the big expensive order will come after I have deposits for the cost of the parts.  Right now it's mostly sitting on my hands waiting for the prototype PCB's to come in, then I'll have to wait again for the final spin of the PCB to come from China.  Since the parts are all from local distribution, I'll order them once all the long lead items are in hand.

Unless OSH Park falls on their ear, I should have a working prototype at York.

gunrunnerjohn posted:

No need for money yet Ron, the big expensive order will come after I have deposits for the cost of the parts.  Right now it's mostly sitting on my hands waiting for the prototype PCB's to come in, then I'll have to wait again for the final spin of the PCB to come from China.  Since the parts are all from local distribution, I'll order them once all the long lead items are in hand.

Unless OSH Park falls on their ear, I should have a working prototype at York.

John:

Looking forward to seeing it at York.  Please keep us informed of the status.

Thanks,

Bill 

Hello John,

We were out on vacation when I found your post on this booster, I replied to the post from my phone but as I looked through all these replies I did not find mine. I don't know if my reply may have gone to Dales original thread which is closed or if it just went out to hyperspace, but, I would like to have you add me to the list of folks wanting to purchase one of these signal boosters for my S gauge layout.

Ray

gunrunnerjohn posted:

Hmm... Shipping to Canada, what's that, about $100?

Sounds about right!  Add another 1/2 by the time Canadian Border Services get their hands on it.

I can coordinate the shipping so that it can be bundled in with my next order from Henning's.  No hurry on this end so whenever it's convenient.

Thanks John

Bruce

Last edited by brwebster

TMCC BUFFER PROGRESS REPORT

The prototype has been assembled, and the bench testing went well, looks like it works just like Dale's original.  A 5V p-p signal in from my BASE1L yields a 15V p-p low-impedance signal out from the 3:1 power buffer driving a 50 ohm load.  Testing with various capacitive loads is ongoing, but it's looking good.  Extended running under load didn't cause any issues, the buffer appears to be loafing doing it's job.

 

Prototype TMCC Buffer on the bench.  The blue LED is power, the green bi-color LED is indicating good signal strength.  For a truly weak or no signal, the LED will be red.  For a low amplitude signal, but still probably usable, the LED will be extinguished.  I find that most old TMCC bases don't have the signal drive to light the LED, but the three Legacy bases and the BASE1L that I tested all had sufficient amplitude to light the green signal LED.  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.

 

Prototype TMCC Buffer in enclosure, The power and signal strength LED's project through the top.  There is no signal applied, and as you can see, the signal LED is red in this shot. 

Right away I spotted one issue, I put the LED's too close to the edge of the board and they don't come through in the recessed section of the top.  I also had to trim the board a bit as it was about 1.5mm too large for the enclosure.  I didn't actually have the enclosure in hand when I did the board layout, and my guess of clearances was just a bit off.

 

Armed with the mechanical knowledge gained by assembling the first prototype, I did a re-spin of the board to fix all the things I saw wring with the first layout.  I optimized the buffer circuit section component layout, and sized the board properly for the enclosure.  I also moved the LED's so they'll be correctly positioned on the flat part of the enclosure.  The holes in the middle of the board mount the board on the bottom plate of the case.  Hopefully, this is the "final" layout.

We are sailing along!

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FYI, here's the complete "package" that will be included with the buffer.  Obviously, the buffer box itself, then there's the 24V power supply, and the earth ground tap cable.  That cable goes between the TMCC or Legacy base power brick and the base itself.  The single wire is connected to the barrel of the base power supply which is the earth ground (3rd prong of the outlet).  This is connected, obviously, to the earth ground terminal of the TMCC buffer.

Yes, there will be nicer looking labels, but I didn't have them yet, so I just taped on the connection data and the name.

TMCC Buffer Complete Package

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I'm targeting probably about a month to six weeks for firm commitments.  At that point, anyone that wants one will put down a deposit to cover the cost parts as I don't want a lot of expensive parts around that I don't use.  The deposit will be on the order of $50.  At that point, I'll make the final parts order for the quantity that I have deposits on.  When they're assembled and tested, all the folks with deposits will be notified and make shipping arrangements.  Right now, the final price looks to be $129 including the $20 donation for each unit going to the ACS in Dale's memory.  That gets you everything you need to install it, the buffer, the 24V power brick, and the earth ground cable to tap off the earth ground from the TMCC/Legacy power cord.

TMCC Buffer Complete Package

 Given the realities of ordering printed circuit boards in quantity, I'll probably have blank boards after the initial build, it doesn't really cost much more to order 100 vs 50, around $10.  At that point, my plan is to make the design available for anyone to assemble that missed out on the initial build.  Since I'll likely have blank boards, those will be available on a first come, first served basis until they're gone.  Obviously, certain parts will be more expensive in quantity one, and things like the enclosure I'm using may no longer be available, that's the downside of waiting until later. 

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  • TMCC Buffer Complete Package
Last edited by gunrunnerjohn

Hello John.

I vacillated back and forth as my new layout under construction could be considered "large". It is multi-tier and passes thru (2) enclosed drywall areas but without scenery or anything else to block a signal...I do have a earth ground wire but notice some areas (especially in the rooms)  that may be an issue.

Bottom line, if it is not too late....please add my name to the list for (1) unit.

I would rather be prepared now than regret my decision later.

Thank you for providing this service to us all.

Donald

Last edited by 3rail

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