Large Scale Central

LGB 20140 Sound and battery install

Electronics Power and Sound
#21

insulate all those loose boards

Insulate? What for? (http://www.largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-cool.gif)

Actually, all of them except the sound board are encapsulated in plastic as if they have been dipped. You can see the slight sheen in the ESC and the RX. The sound board is sitting on a metal rod, so there’s some double-sided foam tape underneath holding it in position and insulating it. With the top (aggregate load) on, the boards are much more carefully arranged, with the SSSS tucked in the side of the sound board.

I was looking around for something to put in the top of the sandbox, as I am missing the curved lid. I found a couple of knobs off a track light bracket which are a perfect tight fit, and have a mesh-type texture inside the lip. I like it!

20200114_101654_sand-dome
20200114_101654_sand-dome756×1008 280 KB

And a little video which shows off the sound system and all those whirring valve rods!

#22

Pete Thornton said:

insulate all those loose boards

Insulate? What for? (http://www.largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-cool.gif)

Actually, all of them except the sound board are encapsulated in plastic as if they have been dipped. You can see the slight sheen in the ESC and the RX. The sound board is sitting on a metal rod, so there’s some double-sided foam tape underneath holding it in position and insulating it. With the top (aggregate load) on, the boards are much more carefully arranged, with the SSSS tucked in the side of the sound board.

I was looking around for something to put in the top of the sandbox, as I am missing the curved lid. I found a couple of knobs off a track light bracket which are a perfect tight fit, and have a mesh-type texture inside the lip. I like it!

And a little video which shows off the sound system and all those whirring valve rods!

Pete,

A word of caution.

I would not put the insulation properties of a conformal coating (dipped in plastic is generally poly-urethane) in good stead, it is usually at its thinness at the point of the soldered component leg.

From personal experience of many years in the aircraft electronics field, I have seem many a board failure due to vibrations rubbing through the coating and exposing the solder joints which then shorted out.

I use an insulation covering over the solder side of all my boards as a precaution, I use the plastic that is used for covers of reports available at a stationary store (also makes good window glazing).

I have also read somewhere (can’t say where) that double sided tape is not a very good insylator.

#23

Indeed I see:

clear heat shrink on the RX

clear heat shrink on the esc

something on one of the triggers

but

nothing on the MLS board

bare pins exposed on the receiver

nothing on the other trigger board…

Just stating what I see, but I will say that the clear heat shrink should not have issues like the ones described for conformal coatings, and you do indeed have to watch that with conformal coatings.

The amount of exposed metal still makes me a bit nervous, but as long as you don’t let the magic smoke out, all is well!

Greg

#24

as long as you don’t let the magic smoke out, all is well!

But I need a smoke generator. (http://www.largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-cry.gif)

Point taken. These boards are (mostly) too expensive to not give them adequate protection.

#25

Greg has a valid point.

Any bare metal can cause a problem.

For the bare servo pins on the RX I will be supplying no charge push on dummy servo plugs, without wires, that will cover the bare pins.

For pcb’s that have bare backs I recommend mounting the component on a thin sheet of styrene. Regular double stick foam tape works well.

#26

Just a note on insulation, on some boards, notably ESCs and decoders, you want to allow a little air flow on the output transistors. I favor a sheet of styrene as Tony states over double stick tape that conforms to the surface and is an excellent thermal insulator.

Please note this is just for components that can generate heat.

Greg

#27

For pcb’s that have bare backs I recommend mounting the component on a thin sheet of styrene. Regular double stick foam tape works well.

The sound board has “regular” foam double stick on the back, with the cover tape on it on the outside, so I don’t think that’s going to cause problems. I got out the little shiny plastic insulator bag that one of them came in and cut it in half - the RX is inside it with plenty of air space, and the ESC is in the other half.

#28

If you are talking about the silver-grey bag, that is static conductive and should never be used when the board is powered. Likewise pink bags are usually static conductive. This is not a dead short, but can cause issues with microprocessors.

You want an insulator.

Greg

#29

You want an insulator.

How can you tell I was a software engineer, not a hardware guru. I should have known that. (http://www.largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-frown.gif)

There is now a large sheet of plastic between the 2 layers of electronics, and I am pretty sure there’s nothing that could generate smoke.

Interestingly, you may recall I complained about the RS switch? This one has gone flaky on me - the action just stops, but if I flick it on/off it comes back. I ordered some more from China.

For the bare servo pins on the RX I will be supplying no charge push on dummy servo plugs

Tony, I noticed this little mini-receiver on Aliexpress, and I an thinking of trying it. (Those drone guys sure are pushing the envelope.) The wires are supplied with the RX and there are 3 conventional pins on the far side for power. Says it will work on a single 18650.

https://www.aliexpress.com/item/1000008487092.html?spm=a2g0o.productlist.0.0.7eaa2ef9h1g8Qy&algo_pvid=755c8333-8841-4740-b1d3-959b6aac57aa&algo_expid=755c8333-8841-4740-b1d3-959b6aac57aa-56&btsid=b4c38d0e-c6be-4a4a-99f9-20df8a1010be&ws_ab_test=searchweb0_0,searchweb201602_4,searchweb201603_55

#30

Looking good Pete… I am both hardware and software engineer, double major, anything to avoid going to social sciences classes ha ha!

Been around long enough to remember the “Bad days” of static sensitivity, where you could blow up your ram chips putting them in the motherboard.

Greg

#31

Hello Pete.

I don’t know anything about the Rx you are contemplating other than it is a manual bind type. You will of course need to gain access to it for binding.

Those are non standard servo pin sockets so may create a problem when used with servos or ESC connections.

#32

Pete Thornton said:

For pcb’s that have bare backs I recommend mounting the component on a thin sheet of styrene. Regular double stick foam tape works well.

The sound board has “regular” foam double stick on the back, with the cover tape on it on the outside, so I don’t think that’s going to cause problems. I got out the little shiny plastic insulator bag that one of them came in and cut it in half - the RX is inside it with plenty of air space, and the ESC is in the other half.

If “double stick foam” is the same stuff that is known a “double sided tape” in Australia then I will offer this word of warning.

I have just (today) unpacked my locos that have been packed away in boxes for just over a year and the adhesive on the double sided tape on a few has failed completely; they were stored in a a room inside my house till I moved and in a cool, shaded environment at the new place.

I will be re visiting the mounting in the near future before trying to run them, and will keep an eye on the new tape…

The adhesive appears to have dried out and will not stick to anything even my fingers which it used to do when I was mounting boards.

So far all the NiMH that were packed with a full charge have held their charge well and are recharging OK. The LiPo’s had a storage charge in them and appear OK as well.

Now all I have to do is lay some track to run them on and that is in the works.

#33

Greg Elmassian said:

Looking good Pete… I am both hardware and software engineer, double major, anything to avoid going to social sciences classes ha ha!

Been around long enough to remember the “Bad days” of static sensitivity, where you could blow up your ram chips putting them in the motherboard.

Greg

Saw a demo from 3M where you touched a terminal on a machine then a discharge terminal till you felt the zap.

Then a chip had its performance checked then was given a zap with a charge that could not be felt by the person handling it and its performance was tested again and the damage done was incredible and the handler felt nothing.

This was when the F/A18 was entering service and we were testing/repairing the CCT boards. We used to refer to being “wired for sound” (sorry Cliff) when working at the anti static stations.

Ahh the good old days when you had to find the fault, as compared to today where the aircraft tells you whats wrong.