[ephrank]

Hi all DIYers,

Last weekend I purchased 2 metal enclosures[*] for my beta22. Yesterday I realised that the enclosures may not give me the best EMI shielding. Here's my reasoning: the enclosures panels are made of steel and aluminum, while this is good in itself all the panels also have a what they called "enamel" finish, which is sort of like spray paint. As a result the panels have a non-conductive surface. My question is: do panels with non-conductive surface defeat the purpose of metal chassis, which is to provide excellent EMI/EFI shielding. Am I still be able to build the amp with a proper 'chassis ground'? Your input is much appreciated.

[*] Link to enclosure product description: 2 Unit - Pro Grade 19inch Rack Style Equipment Enclosure - Jaycar Electronics

 

[johnwmclean]

These are perfect, the inside remains conductive, and can be properly grounded.

 

[johnwmclean]

These are perfect, the inside remains conductive, and can be properly grounded.

Edit: I assume it's not coated internally that is.

 

[ephrank]

All panels are coated inside and out.

 

[qusp]

ahh; you will just have to file it back in the places you wish to attach your ground plane. the paint wont effect the case's ability to attract EMI and RFI.

 

[ephrank]

In my case the panels are electrically isolated from each other, does it make the enclosure's EMI blocking ability weaker? I guess it is like having a shield the interconnect able but not connecting the shield to any ground? If I use the file method, do I need to file a spot on every panel and then connect them together (with hook up wire I suppose) at one spot? Sounds messy.

 

[qusp]

how are they isolated from each other?? either way yes ideally you should have all sides grounded. you could just make a loop of wire that encircles the case and ground that after filing a spot for it to contact to; then just ground that wire.....

I dunno, never been faced with a situation like that; was this case designed for audio?? or at least electronics?? seems like an oversight

 

[johnwmclean]

ephrank, if you’ve still got the receipt and your worried maybe you should do a return? Swap them for connectors or something else you need for the build... just an idea.

 

[kklee]

If all the panels are coated, you'll need to scrape off some of the coating where the panels touch together to ensure that they'll conduct. I've had to do this with other rack style cases before. After you re-assemble the chassis, just use a DMM to ensure that the entire case has continuity.

As an aside, plain steel and aluminum are not very good for blocking strong EMI. It'll mostly be RFI that you'll be shielding against. Ensuring that the entire case has continuity will help with noise caused by grounding issues.

 

[ephrank]

Thanks all for the input

I've just test the enclosure again with with my DMM and guess what, I worried too much. There are 4 zinc plated steel rods reinforcing the side panels and front/rear panels. I tested the rods and they all have continuity between each other, which means the enclosures are all fine

I guess what happened was a bit of the paint finish was rubbed off while I tighten the screws.

 

[johnwmclean]

ephrank, that is good news

How is your build progressing?

 

[ephrank]

Hi johnwmclean, tomorrow I'm going to bunnings to get some drill bits and misc. tools. I've also ordered a Goldpoint mini V. I'm using Inkscape (a free software clone of Illustrator) to do the panel designs. Busy busy...