[sdiy] Siel OR400 power supply busted

[maeghan]

What I saw could have just been the initial spark when the power socket's lugs touched the heatsink. It might not have arc'd over other boards. Light moves out so it might not have touched many components at all. I don't know. Everyone here has been very helpful and given me instructions on what to do to start troubleshooting the synth. I'm gonna start to follow the steps today. 

I know for certain that the LM13700 chip needs to be replaced. I'm gonna place an order with tayda electronics and spend about 10 or so bucks and order some chips.

I've got a good little inventory going of electrolytic caps, poly film caps, resistors, ceramic caps, and various power sockets to use for building pedals. 

I don't have poly film box caps. The siel uses mostly the box style caps (they are a lot neater to use.) I'm mentioning this because I'm buying chips today and am gonna start troubleshooting and diagnosing the siel today. So if I discover a bad box cap... I'm gonna have to order them and therefore wait.

ok, guys ... thank you. if i have any questions ill post otherwise, i'll post the results of what I find.

thanks ~ maeghan

Sent from my iPhone

On Aug 7, 2013, at 3:38 AM, "cheater00 ." <cheater00 at gmail.com> wrote:

> 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.