Safgan (DT-520) Oscilloscope

[Nick]

I'm wondering if the cap and whatever the other item was were not a filter but a snubber for the mains switch... that would make sense along with the 100nf value.

Nowadays you must use an X2 type cap rated at 275 vac or more connected across the cold side of the switch between live and neutral.

If the "other item" was connected in series with the exploded cap I'd just forget it for the moment...

[AlanBeckett]

Looking at the picture there appears to be 4 sleaved wires on the (Mains) Switch. Below them are the three tags belonging to the Intensity Pot.
Next down is the Focus Pot.
Where were any of the 'missing' components connected to? Not the switch I think.
Or am I getting the wrong end of the stick.

Alan

[Nick]

When I first looked at the photo, it was on my phone and not very clear. Looking at it again on a monitor it does appear strange that there is nothing obviously missing... I still think that there should be a snubber on the back of the switch.

Further, if a cap explodes, generally you are left with a couple of wires sticking up looking lonesome and unloved - It's unlikely that the wires would evaporate so neatly as to completely disappear...

I'd go looking for lonesome wires associated with carbon deposits

[Bobsy]

   

I would expect it to be a thermistor and not a diode at all.
Can you draw out a circuit of where the parts blew off from?
Do you still get power to the scope?

Yes I get a signal, but only in Auto Scan and it does not respond to Vertical Control anymore! Also I need to apply almost 'Full' Intensity to maintain the Signal which eventually drops out of vision after 5 mins. Its turning out to be a bit of a conundrum, as unless I attach some resistance or the cap across a couple of posts I get nothing. It was working fine before disaster struck.
All your suggestions have been very much appreciated At least it gave me some ideas - might have to put this job on the back burner

[pwdrive]

Have you checked the intensity pot? And the voltages on it?

Lawrence.

[Bobsy]

Looking at the picture there appears to be 4 sleaved wires on the (Mains) Switch. Below them are the three tags belonging to the Intensity Pot.
Next down is the Focus Pot.
Where were any of the 'missing' components connected to? Not the switch I think.
Or am I getting the wrong end of the stick.

When I first looked at the photo, it was on my phone and not very clear. Looking at it again on a monitor it does appear strange that there is nothing obviously missing... I still think that there should be a snubber on the back of the switch.

Further, if a cap explodes, generally you are left with a couple of wires sticking up looking lonesome and unloved - It's unlikely that the wires would evaporate so neatly as to completely disappear...

I'd go looking for lonesome wires associated with carbon deposits

OK you got me Googling for the word 'Snubber' now! lol

[Bobsy]

Have you checked the intensity pot? And the voltages on it?

Lawrence.

Will do asap, and get back to you on that. Cheers

[AlanBeckett]

Be careful as there could be a lot of volts on there.

Alan

[pwdrive]

Quite a lot of volts.....

Lawrence.

[Bobsy]

Thanks for the heads-up Alan, I'll be fully Rubberised and goggled-up