[sdiy] Siel OR400 power supply busted

[cheater00 .]

On Tue, Aug 6, 2013 at 5:43 PM, Needham, Alan <Alan.Needham at centrica.com> wrote:
>
> If the PSU output was disconnected is it really likely that the short could damage anything beyond the PSU?
> I have seen mains shorts creating flashes that lit boxes up, could it be just that? Light bouncing around in the box?
> Maybe there is something else causing the issue here, the PSU is OK now, keep going!

The approximate rule for arcovers in air was ~ 30 kV/cm, so at up to
220V - unless we're talking about a tenth of millimetre in distance -
no. And then, why would it arc towards a PCB that doesn't have a
separate connection to ground - it doesn't complete the circuit. But
maybe something got statically charged, and created ESD damage on that
other board. I haven't experienced ESD which creates sparks visible in
daylight.

On Wed, Aug 7, 2013 at 2:09 AM, M Maeghan Skala
<synth.diy at pulsewidthmod.com> wrote:
> Yup, ba banana's work … (a friend who was recently over here said the banana's didn't fit … but they do.)

If it's a General Radio binding post you can remove the screw-on
button and are left with a terminal that will mate with safety probes
that have the plastic sheath over the "banana" plug. If it's just a
jack you have to use an adaptor or break your probes to expose the
binding post plug. However since it uses differential input they are
more likely to be fixed recessed sockets.

> On my scope one side is labeled "V-Pos" and the other side is labeled "H-Pos"

> V-Pos has four inputs and a ground input, H-Pos has 3 inputs and a ground input
>
> V-Pos: Z-Axis, 60 ~, V-Input and an unlabeled input, final input is ground
> H-Pos: Ext Cap, Sawtooth, H-Input, Ext. Sync, and final input is ground

The "V-INPUT" jacks are the ones below the label, not above.

It's a differential input. The middle connector is normally shorted to
the bottom one that's ground via a metal plate like here:

http://www.museu-tecnologia.com.br/wordpress/wp-content/uploads/2010/07/hpim58241-419x500.jpg

This is how you want to operate it. You'll put a probe from your
circuit's ground to the middle input and use a probe connected to the
top input to measure the signal. Before you connect the grounds
together via the ground probe you use a multimeter to check that the
voltage between both sides of the connection is zero or millivolts.
Otherwise you'll blow your scope up.

Before you turn on the scope, turn intensity all the way down,
assumedly that's all the way left. Then bring it up very slowly until
you get a faint trace. If you use intensity that's too high, even for
a second, you'll put burn out on your CRT and break it. This guy's
running it too bright:

http://b.vimeocdn.com/ts/194/478/194478591_640.jpg


> So, am I right in assuming that I'd plug one probe into the "V-Input" and the other probe into the "ground input"?
>
> Maybe I should spend a day or two learning about scopes …

Play some music from your computer. Connect the jack sleeve to the
ground (check potential with voltmeter first), and the tip to the top
V-INPUT. Turn knobs (except for intensity) until you can roughly match
what's on your wave editor. Use a software tone generator, generate a
sine or square, and get stable display using the phasing and sweep
selector knobs.

But first of all, start up your oscilloscope and let it sit for an hour.

D.