HDPlex linear PSU has blown up my SEG!

[Getgaff]

Is 15.27v sufficient to cause damage to my SEG?

Installed a HDPlex linear PSU this morning and hooked the SEG to the DC19V output that I’d internally adjusted all the way down to 15.27v (won’t go any lower). After approx. 30mins lots of smoke pouring from the Caiman. Unplugged it all, whipped off the top to reveal a blown capacitor and a certain amount of wetness inside:

https://imgur.com/gallery/ddnsk

Not happy to say the least and very concerned about the risk of more serious damage (i.e. ignition and fire).

Any advice gratefully received.

[Getgaff]

And my RPi3 and my Roku Premiere+

FFS

[jandl100]

Oh no.
Cripes.
Nightmare. :(

[struth]

Must have been putting out more than the seg can take. Put a metre across the plug and see what's really coming out of it

[Getgaff]

I did measure the output voltages before plugging everything in:

Fixed 5v = 5.25v
Fixed 12v = 12.25v
Variable 5v-19v = 12.1v
Variable 15v-19v = 15.27v

Checked and rechecked and when plugging in the Roku, it sparked and bizarrely the RPi3 went up in smoke. Roku also fails to power on now.

Turning into an expensive day :(

[struth]

Deffo dc

[Getgaff]

Yep, definitely DC. Unless I have seriously misunderstood it’s capabilities, I’m at a loss to understand why it’s all gone wrong.

RMA request made.

[struth]

Got the tips right way round I take it. I would also check for ac in case

[Light Dependant Resistor]

This suggests a case of incorrect polarity arriving at the Dc connector. The Caiman as I see is designed for its own power supply
so much caution needed connecting anything else.

However it should also if well designed for the real world have either a forward biased diode, meaning that it is connected with anode in cathode out to the supply, or a shunt diode meaning anode to ground and cathode to supply. The part that has failed internally is likely to be the capacitor seeing reverse polarity ( without a diode ) which aside from leaking its electrolyte can also explode, however it looks like SEG Caiman have fitted a resistor which is the part that caused the smoke and this has limited the current. So slightly messy, but unlikely to have totally damaged the unit, rather replacement of parts, or the power supply section itself.

Slightly over 15 volts really should not have caused any damage, but I would need to see a schematic to confirm.

A good electronics shop could repair, but better return to SEG Caiman, who will either replace under warranty ( maybe ? )
or fit a new power supply.

So it does not happen again once it is repaired , you need to fit a forward biased diode inline. This will involve modifying the cable to have a diode fitted. The diode slightly drops the voltage too. The diode needs to be rated to well within the current rating drawn by the SEG Caiman
and its voltage too needs to be considered, although voltage is easily normally catered for- as its hard finding a diode rated under 100v.

Cheers / Chris

[struth]

This suggests a case of incorrect polarity arriving at the Dc connector. The Caiman as I see is designed for its own power supply
so much caution needed connecting anything else.

However it should also if well designed for the real world have either a forward biased diode, meaning that it is connected with anode in cathode out to the supply, or a shunt diode meaning anode to ground and cathode to supply. The part that has failed internally is likely to be the capacitor seeing reverse polarity ( without a diode ) which aside from leaking its electrolyte can also explode, however it looks like SEG Caiman have fitted a resistor which is the part that caused the smoke and this has limited the current. So slightly messy, but unlikely to have totally damaged the unit, rather replacement of parts, or the power supply section itself.

Slightly over 15 volts really should not have caused any damage, but I would need to see a schematic to confirm.

A good electronics shop could repair, but better return to SEG Caiman, who will either replace under warranty ( maybe ? )
or fit a new power supply.

Cheers / Chris

Yup i asked about the tip but no reply so far.

[Light Dependant Resistor]

Yup i asked about the tip but no reply so far.

Yes well spotted Grant, and highly likely to be the cause of the fault, But Gareth's SEG Caiman - its design should have predicted the possibility of incorrect polarity occurring in the first place.

[struth]

Yes well spotted Grant, and highly likely to be the cause of the fault, But Gareth's SEG Caiman - its design should have predicted the possibility of incorrect polarity occurring in the first place.

thought it would be fused tbh. A lot of ac onto the cap could do it too if the psu is faulty but tip polarity is most likely at moment

[Light Dependant Resistor]

thought it would be fused tbh. A lot of ac onto the cap could do it too if the psu is faulty but tip polarity is most likely at moment

I looked up the user manual, and there is a fuse fitted internally of 2A rating, but it looks like it did not provide needed protection on this occasion.

[Getgaff]

Checked the pins, all are DC centre positive. I’m mystified.

[struth]

..need to get it on a scope and see whats happening Garath. Something seriously wrong if its taking everything out it touches.

[Getgaff]

It’s going back next week for a full refund. Not sure if I can claim for the subsequent damage, perhaps chalk that up to experience and the perils of fart-arsing about with electrics.

[Getgaff]

Not too bothered about the RPi3 going up in smoke TBH; the Roku dying irritates me but that was a glitchy POS, but the Caiman SEG? Seriously miffed. I’ve reached out to Stan by email to ask for his help, see if I can get it repaired.

[struth]

no harm in asking, but unless you get proof it will be difficult. Happened to me last year, I got something on loan/ trial that took out a monoblock which is still u/s. I decided to just give up on it and put it down to experience... Still miffs me tho.

[Getgaff]

I can’t prove I didn’t plug the 12v/15v output into the 5v RPi3 and that I didn’t plug the 15v output into the 12v Roku and so on. I’ll be sure to mention it when it goes back, but I’ll chalk this up to experience and perhaps a lesson to myself that tweaking doesn’t necessarily bring about positive results.

Thanks all for the input though, appreciated :thumbsup:

[Theadmans]

You are not the only this has happened to.

I have a Chinese Linear Power supply that provides 15v for the SEG and 5v.

I recently killed my Squeezebox Touch by putting 15v into it instead of 5v !

I have now replaced it with a Raspberry Pi and Wolfson Audio Card running SqueezeLite.

I have also colour coded the power leads now (strange how these things only get done after the event)

I met an Electronics Engineer at my sons radio controlled boat club yesterday - he has kindly offered to see if he can fix the Squeezebox Touch for me.