Finished up my second sound install. Turned out better than I'd hoped. Sounds great! Sent from my LG-H918 using Tapatalk
Hi Ben. Very nice - you've obviously mastered the techniques! I have one small suggestion that you might want to consider. After years of using standard round 1/8-watt carbon resistors (like you are doing), I decided to try to go smaller. What I did was use 1/32" single-sided PC board, and 1/8w surface-mount resistors. I cut slots in the board (an elongated cross; one slot is horizontal, to separate the board piece into two halves, and one is vertical to make the two halves into two "circuits" that are bridged by the SMT resistors) to create two "circuits," solder the SMT resistors across the vertical slot, and I end up with a very compact package that is about 1/16" high by 1/4" wide by 3/16" deep. Here's a photo of the pieces of board with the "cross" cut: And here is a photo with the resistors soldered on: After I've completed the soldering, I trim the ends of the boards back if necessary with flush-cut nippers. The boards can then be glued to the frame with a small drop of thick CA, or even put in place with thin double-sided tape. The total package is smaller than two round carbon resistors, and in particular, they take up significantly less height, which is key to fitting everything under the shell. Soldering these tiny things is a bit of a hassle, but pretty straightforward once you get used to the technique (you put a coat of solder on the board, then pick up a resistor with tweezers and put it across the vertical slot, holding it in place with the tweezer tips. Now you touch your hot, tinned iron to one side and let the pre-tinned solder flow around one end of the resistor, then do the same for the other end, then you're done - you'll probably ruin a few at first, but since they cost a fraction of a cent in lots of 100, no big deal). Here's a photo of one of my boards in use on an installation in a Kato PA-1 (I took this before I finished the installation of the LEDs, so only one side of the board is wired, but you can clearly see how small it is in comparison to everything else): If you're planning on doing a bunch of narrow-hood diesel installations, this technique is worth learning, and the parts cost is minimal - you can get 1/32" single-sided copper board and the resistors from Digikey for under $10 total, and one 6x4" board will make hundreds of these mini-resistor circuits. John C.
John again, thank you for your advice. I've actually chopped the parts list you posted earlier and plan on using these updated ways of doing it. Lol, I just bought 100 of both the 1K &2K so I'll probably use them when I can but the smaller the better! I do have a question though. The Caps you use are black in color and mine are the tan colored ones. Are the black ones smaller in size as well? Sent from my LG-H918 using Tapatalk
John, I do have a question though. The Caps you use are black in color and mine are the tan colored ones. Are the black ones smaller in size as well? Sent from my LG-H918 using Tapatalk
You are correct but I'm referring to the Caps he uses for his stay alive. Sent from my LG-H918 using Tapatalk
The caps are the same size - all the 16v, 220uf tantalum chip caps are basically identical. I think mine are AVX caps, but I'd have to check to be sure. John C.
I have used both caps, black and tan, together. In my SD-26, I somehow managed to find space for eight of those capacitors in the space between the shell and locomotive and the ESU LokSound decoder. In all my DCC installs, I've learned from the master (John) and I can find space for at least four of those capacitors in each locomotive. Sometimes I can put in a lot more if space allows.
And a word of advice about the caps: put Kapton take UNDER the caps if they touch each half of the metal chassis. They WILL burn the decoder if you don't (don't ask me how I know this).
Hi John, thanks for the tips. I have a supply of SMD resistors and the circuit board but the board doesn't appear shiny like yours. Is there a layer that needs to be removed and how do I go about doing it?
The board probably has some oxidation. Take a wire brush or some fine (400 grit) sandpaper and go over the surface lightly until it has the copper shine. John C.
Happy New Year John. I hope all is well with you in the new year. A quick question when you get a moment please? How do you cut your copper clad board so neatly?
I use a 1/64" end mill in a milling machine, with the board mounted in a machinists vise. But you can do almost as well with a thin cutoff wheel mounted on a dremel. Draw lines on the board with a pencil and a drafting square (or just a ruler), and then very lightly go over the lines with the cutoff wheel running until you have cut through the copper. The key here is "very lightly" - you want to just cut through the copper, not cut through the board (yet). Once you have cut your lines for the circuits, THEN you can use the cutoff wheel to cut through the board itself to make pieces. But you might even want to solder on the resistors before you cut the board into pieces. That way, you can cut off as many (or as few) "circuits" as you need for a particular installation - for example, you might need only one such circuit (headlight only), or you might need three or four (headlight, backup light, Mars light and perhaps separate marker lights). Once you decide how many lighting functions you are going to wire up, then you can cut off however many you need from the larger piece of board, again using the dremel with a thin cutoff wheel. John C.
