Advice Needed V-Box blew up :(

[Vipersan]

Liking the progress so far VS! Once you're done, I want to start rebuilding mine.

I play badminton with a guy who runs an electronic engineering firm (http://www.apuljackengineering.co.uk/), so he has easy access to many parts. He said dual output (24/12v) SMPSs are quite easy to come by, so he'll check what's available. I am guessing the 12v side doesn't require a lot of current to run - 1A max for two boards should be enough?

I understand the PS you have only has a 24v output at 8.3A. Do you put that directly into the L7805CV regulator do you step it down a bit? That side runs on 5V from what I see.

Yep ..you are quite right ..
12v is not needed really ..
5v is the required voltage for the electronics ..
Ideally you could step down to 12 first ...but the 7805 should be ok with a full 24v on the input which is what I'm doing ..
I remove the regulators from the pcb and mount on a seperate heatsink ..cos they will run a little hotter than freestanding as they currently are ..
but I have already tested with 24v directly on the freestanding 5v regulator for several hours ..and although it runs hotter than I'd like ...it didn't fail and didn't have me worried.
rgds
VS

 

[Captain Jack]

Yep, thanks VS. That's what I thought regarding the heat. In any case, as a whole, it will run much cooler (and quieter!) with an SMPS than a huge AC transformer...

 

[battenfan]

I've had 78xx stabs shortened for unknown reason and it ruined the electronics it supplied. To avoid Murphy's Law, add an extra zener after the 7805 and a fuse on the 24V to be on the safe side.

 

[Vipersan]

Gonna have to take another break ...but this is what I have so far ..
Note the surplus diodes have been removed from the Gbox pcb ..
Also the motor terminal strip which will be mounted to the rear on the back plate ...linked with wires
As will the F connectors ..also removed.
The 5v regulator can be seen ..having been mounted off pcb ..with three wires ..currently visible to the left in the photo on a block of ally ..with room for the second 5v regulator from the next Gbox pcb ..
which will be mounted above the first one on the stand offs you can see in the photo.
So more to do ..but am taking a breather before I start making mistakes.
rgds
VS

 

[Vipersan]

Not the best photos ..but here is the box closed with 1 x pcb ...the heatsink and the cut down psu inside..
you will note to the rear that due to the shape of the psu ally frame I had to allow a small chunk to stand proud ...but not very destructive and easy accommodated with a few cuts and possibly a bit of plastic strip..
enough for now..
rgds
VS

 

[Vipersan]

A bit more ...

 

[Channel Hopper]

Impressive(ly) speedy constuction Evan

 

[Vipersan]

Done for today ...
This is the back panel complete...
;)

 

[Vipersan]

Impressive(ly) speedy constuction Evan

Thanks CH ..
quick smoke ..and then a long soak in the bath I have running..
More tomorrow.

 

[Channel Hopper]

Thanks CH ..
quick smoke ..and then a long soak in the bath I have running..

Blown it up already ?

 

[Llew]

That's coming on nicely VS. A well thought out layout.

Does the SMPS have any feedback circuit in case of secondary component failure? I couldn't see the familiar 4-legged optoisolator anywhere - maybe hidden from view, or some other means used?

 

[Vipersan]

Yes Llew the psu uses optos and even has a 110/120v switch on it ..
Also claims to use short circuit protection for the secondary...but no reason to test this ..lol

..anyway ..
prepared and mounted Gbox 2 pcb this morning ....but may have overdone it yesterday health wise as I'm tired and have a blinding headache atm..
Still ...progress being made..
Here is the pic

 

[Captain Jack]

Brilliant stuff, VS! Sorry to hear it's taken a toll on you physically - hope you recover from this quickly.

Time to order some bits for mine - it's been an inspiration

First I want to test the controller side of blow board with some old power adapter...

 

[Vipersan]

Well...

I'd call this a successful test ...
I admit I was a bit worried that the perspex I chose might dim the numbers too much ...or worse ..
prevent the IR signals getting to the sensors ..
Having cut a slice and fitted it ..
The only way to get the unit(s) out of standby was by remote control ..
et voila ..
very responsive indeed..

 

[Captain Jack]

Nice! Have you devised a method to switch between the two yet?

Just tested mine and the board is still alive - thankfully!

 

[Vipersan]

Nice! Have you devised a method to switch between the two yet?

Just tested mine and the board is still alive - thankfully!
Excellent News Buddy

Not as yet CJ ..
Will complete the build before any experiments..
2 x rocker switches to control each Gbox will be fitted on the front panel anyway ...
rgds

TBH the logic is already there insofaras one unit out of standby ..and one unit in standby ..will auatomatically toggle states on one single remote power button press since both sensors are in close proximity ..
..once the tactile buttons are made available on the front panel ..
This initial 'state' ...is easily achievable manually..

VS

 

[Captain Jack]

OK. I am trying to come up with some logic circuit diagram to keep one of the boxes off when the receiver is switched on. They would then be switched on/off in an alternate pattern by hitting the power button on the remote. Of course, still have to make sure that all DiSEqC commands get through, etc...

 

[Llew]

Yes Llew the psu uses optos and even has a 110/120v switch on it ..
Also claims to use short circuit protection for the secondary...but no reason to test this ..lol

Ah, belts'n'braces ;)

 

[Vipersan]

Nothing easy about drilling and filing perspex ..
It is easily cracked ...and scratches too easily ..
So ...took my time filing out rectangular holes for the rocker switches ..starting with a 2mm drilled hole and working upwards to 1cm in 2mm steps ..
Glad that bit is over anyway ..
lol

 

[Vipersan]

Almost there ...
Still have to connect the 2 Gbox power rocker switches ...but at least I now have button control of each unit..
Nice..

..and I'm so tired today ..I think I'll take myself to bed early..

looking good tho'
rgds
VS