[sdiy] Covers / shroud for unused header pins?

James R. Coplin james at ticalun.net
Fri Sep 6 21:12:38 CEST 2024


Basically, the cabinet has two of these installed for LED control.

https://www.ultimarc.com/output/led-and-output-controllers/pacled64/

As you can see, they have two large headers of pins for the led controls 
and since I'm using 2 of them, there are a significant number of unused 
pins. I have to use 2 because some of the leds are 5v and some are 12v. 
The whole cabinet is filled with point to point, crimped on spade type 
connectors. Troubleshooting an intermittent ground connection pretty 
much requires having it on and poking around. Further, because the 
control panel takes a lot of physical use and vibration from button 
presses, disgruntled fist smashing, etc, things can come loose since the 
connection are friction not soldered. The spades do have insulation on 
them to try and prevent shorting but even so, I had a loose connection 
hit the pins at just the right angle that the inside spade connected 
across pins and blew out a board. I probably couldn't do it again if I 
tried but the way my luck goes, I don't want to find out and that's why 
I was looking for solutions.

The corrugated cardboard suggestion seems like a really good one and I 
will probably try that or some foam core. I'll probably just end up 3d 
printing something or use terminal housings that match with the minimum 
number of empty terminals installed for it to grab. The ribbon cable 
type connectors would be great but they aren't meant to go right next to 
each other so probably wont work either.

James

Nathan Trites wrote on 9/6/2024 11:43 AM:
- show quoted text -


Nathan Trites wrote on 9/6/2024 11:43 AM:
> I completely agree, opening and closing the case isn't the issue here 
> - precaution is. Maneuvering and working with live circuits is an 
> inherent part of diagnostics and repair, and depending on the device 
> there are infinite ways to cause shorts during routine work.
>
> Personally, I'm surprised there's 20 posts of advice in this thread 
> and no one's asked exactly what kind of header/connectors James is 
> working with! Since it's an old arcade cabinet, I'd assume a mix of 
> edge connectors and molex? Immediate advice: put heat shrink over the 
> spade terminal. Any bigger free floating connectors just use larger 
> diameter heat shrink (1" etc) long enough so it doesn't make contact 
> with other parts. If you need to easily remove and re-insulate, some 
> kind of tape. Florian's initial advice is the right move for most 
> friction connector types.
>
> Think thru the scenarios:
>
> If the header is always exposed and could be considered a design flaw 
> or allowed to happen due to other design choices (e.g. you need to 
> have various connectors unsecured in order to work on it), having a 
> way to cover the headers when not in use makes perfect sense. I'd 
> create a dummy connector of the same type (with crimps inserted if 
> needed), and if the connector type doesn't have a cover or covered 
> version available, fill the cable opening with silicone RTV or hot glue.
>
> If they were left exposed in the course of repair and the risk of 
> shorting is there again... If they're low voltage/current I'd probably 
> just put blue painters tape over them until they're needed again, or 
> some type of Kapton, PTFE, or electrical tape which all have other 
> compromises. If they're higher voltage or current, secure the loose 
> connector as best as possible so it doesn't pose any risk, or create a 
> dummy connector for the exposed header and insulate the openings with 
> hot glue or something. As above, cover any free connectors on cables 
> with appropriately sized heat shrink.
>
> Nathan
>
>
> On Fri, Sep 6, 2024 at 10:23 AM Florian Anwander 
> <fanwander at mnet-online.de <mailto:fanwander at mnet-online.de>> wrote:
>
>     Hello
>
>     Am 06.09.24 um 14:17 schrieb cheater cheater via Synth-diy:
>>     i'm still confused as to how unplugging a thing from the wall is
>>     too difficult 
>     hmmm, when I am repairing a device and I have to do measurements
>     or trimming, I will have to open and close the lid a hundred times
>     to change settings on the frontpanel and then get back inside to
>     continue my measurement. Of course I don't want to unplug or
>     switch off the device, for each move of the lid...
>
>     Florian
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