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It's about time (PCB rant)...


Jidis
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Finally got this crap sorted out after a full day of finding shorts and missing lines. It's a DIN/DOUT board with 8 switches and 16 lights (apprx. 2"x4"):

LightswitchTop.jpgLightswitchBot.jpg

Here it is with one of it's hosts, a hybrid JDM/Core with custom headers:

JDMCoreLightswitch.jpg

George

PS- Anybody ever slop something over their traces and jumpers to "freeze" them into position and protect them? Seriously though, I'm considering it. I figure once it works, there shouldn't be any need to access the stuff, and it's nice to be able to throw the things around without worrying about figuring out what you broke later on. Thought about fiberglass resin, silicone, and hot melt glue. Any ideas??

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PS- Anybody ever slop something over their traces and jumpers to "freeze" them into position and protect them? Seriously though, I'm considering it. I figure once it works, there shouldn't be any need to access the stuff, and it's nice to be able to throw the things around without worrying about figuring out what you broke later on. Thought about fiberglass resin, silicone, and hot melt glue. Any ideas??

I would go with Bee wax. I think it is best because it can be melted and removed if needed. Resins, and silicone is not necessery. I used to put alot of hotglue and it was nightmare once I neded to remove it.

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Funny, I just did the same thing with the hotmelt. If you notice, the LCD on that Core has mounting holes. I had standoffs under it, and didn't have long enough bolts, so I just used screws with a glob of that on the bottom (on the tip of the screws). That barely came off and it wasn't even really stuck to anything but "flat board area". :o

I think the gluing I'm looking for on this stuff would be more permanent. The sort of thing where if I needed to change something, I'd rather build it again. I guess you're saying hotmelt is OK for that?

Take Care,

George

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Yeah, I like the Core a lot, but it was a similar pain in the a**.

The area over on the right is a JDM. Above the 9-pin socket is a two way, 5-pin header (3x5), with a group of 5 jumpers glued together. If I pull that off and move it to the other side of the header, it's a JDM (in ICSP mode). The bottom header (with the ribbon) is a 2x5, but rather than the duplicate pairs of pins on the regular J8/J9, it's got the top row wired like the DOUT regular part, but the bottom is the DIN data line, and the three mux lines for analog in (I'll make a ribbon if I do that). The left header is the 8 analog pins, 5V, and ground on a 2x5 header, and the DIP switch under the LCD/PIC can pull down each of those depending on how many I need to use. The LCD is plugged into a sliced off chunk of an old Mac Nubus connector. ;D

I really made it for doing non-MIOS things where I can't dump into a loader, but have to keep reprogramming and rebooting the PIC. I didn't like the idea of having to keep pulling the PIC or having separate boards with an ICSP connection.

Next step is to get a board or two to adapt smaller chips to the 40-pin with their i/o pins going to the right places. :)    -> The xtal is socketed BTW

George

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It always seems that the more sure I am about a board being completed (which leads me to sometimes epoxy-ing in shadily mounted components), the more likely I'll have to sit there with an exacto-knife carefully chipping away the epoxy from the leads of what is invariably the most expensive or hardest to find component on the board.  Beeswax seems like it'd be a good idea, but what temperature does it melt at?  90% of the electronics I've been working on recently has been tube-based, and I doubt beeswax would cope with the high-voltage components.  Maybe some kind of foam that could later be dissolved??? 

On the other hand, if you're securing just jumpers, you could always just desolder it from one side, and cut them out from the other...  Seems like you could still salvage a board after that.

Robin

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My deal would be after everything had been powered up and thoroughly checked. A lot of these things aren't destined for enclosures, so any reinforcement helps.

George

PS@ Robin- I didn't even realize you were that close. I'm right up in Richmond. Still looking for the "good" electronics store here too. Just had to resort to RS the other day for some small junk. Resistors are a dollar for five on 1/4 watts. :-\

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