Does the metal back plate on an Atari 800 provide grounding/connections to the PCB?

[Beeblebrox]

So I've acquired various working Atari 800 parts - enough to assemble the internals for a working PAL 800 unit. (I'd done this before with a test PAL 800 I had out of the case all the time last year. Basically I want to create another test unit as I plan at some stage to tinker with the VBXE carrier board install as well as other projects using it. I want to avoid doing so on my main 800 which already has incognito and have no desire to mess with that one  ). 

 

The only part I am missing for this new project is the metal back plate (where these pics below are taken from my other fully assembled 800 to illustrate it):

    

I know I've run my previous test 800 out of the casing with just the bare PCB and power board, (so no faraday cage or back plate was present) and it worked fine.  

 

My question is this. Given this metal back plate - aside from it's other original purposes of shielding and also mounting the main PCB to the faraday cage - is metal and there are 3 x points on the PCB it makes contact with as indicated below - does the plate itself serve as grounding/connection(s) for the PCB?

 

The reason I ask is what would happen if I replaced the missing back plate, which is a little trickly to replicate easily from metal - with a plastic version I can quickly fabricate. Given it will be plastic, there would be no metal contact at these three points.

As such will this have an adverse affect on things if these are grounding points? I don't think it would but just curious to know.

 

From the looks of things these three points are the only areas the back plate makes contact with the PCB at, and then of course the plate itself is making contact with the faraday cage.

 

If these grounding points are ideally kept in place I am sure I can perhaps use some thin metal foil or conductive paint overlaid on the plastic in these areas to create the same connections.

 

Ideally I'd just source a replacement metal back plate but I think finding one in isolation is extremely unlikely.

Edited February 24, 2023 by Beeblebrox

[TGB1718]

Hi Beeb, it's just part of the cage, those points are just to provide the shield with decent grounding.

 

I've run my 800 completely "naked" and it works just fine.

[Beeblebrox]

@TGB1718  Great. thought so. I have had a working "naked" system before as mentioned, but given I'll be using this test 800 for the VBXE carrier  project, I wanted to make sure I understood the possible issues I might have if these ground points are not in place. I may just carefully apply the use conductive paint on the plastic repalcement plate in these areas. Probably won't. Will see. Thanks for confirming.

 

 

Edited February 24, 2023 by Beeblebrox