Is this safe to use?

[gpraceman]

I didn't really see a forum to post issues/questions relating to demagnatizers, so I am posting here.

Any EE's here?  I bought a vintage demagnetizer and just received it.  There was an oily substance on it, which seemed strange.  So, I opened it up.  Oily stuff all over the inside cover and components.  Leaking out of the capacitors?  Not sure if this thing is safe to use or I should try to return it.

[HectorLooi]

That's the problem with buying vintage electronics. Unless you know how to repair and refurbish electronic equipment or are willing to spend money getting someone to repair and certify it safe, stay away from vintage electronics. 

Those look like film capacitors and are unlikely to leak anything. It actually looks like paper/foil capacitors. Some of them were coated with a varnish to insulate and prevent oxidation of the metal foil. The varnish could have deteriorated into that oily stuff.

Could you get some closeup photos of the markings on all the capacitors? That would help us identify what kind of capacitors they are.

[gpraceman]

50 minutes ago, HectorLooi said:

That's the problem with buying vintage electronics. Unless you know how to repair and refurbish electronic equipment or are willing to spend money getting someone to repair and certify it safe, stay away from vintage electronics. 

Those look like film capacitors and are unlikely to leak anything. It actually looks like paper/foil capacitors. Some of them were coated with a varnish to insulate and prevent oxidation of the metal foil. The varnish could have deteriorated into that oily stuff.

Could you get some closeup photos of the markings on all the capacitors? That would help us identify what kind of capacitors they are.

Well, I was imagining simpler electronics.  I've worked on various electronics projects before, but am not familiar with these capacitors.  One of them looks perfectly fine, but the other 3 look oily/waxy.

Edited December 22, 2023 by gpraceman

[HectorLooi]

Just to be safe, you should replace them with a modern film capacitor. A similar 600VDC capacitor or a higher X2 rated capacitor. 

Do check the big paper in oil capacitor for leakage too.

[gpraceman]

The big silver cylinder, if that is what you mean, doesn't have any signs of leakage.

[HectorLooi]

Do you have a capacitance meter to check if the values are still within specs?

[gpraceman]

No on having a capacitance meter.  I've been researching, and it seems that I should replace them with modern equivalents.  I care more about functionality and dependability than replacing with like components.

I should add a fuse as well.

[JohnR725]

All of your mylar and paper capacitors are probably okay it's this one that I would be concerned about

Especially since something has leaked out from somewhere unless it had leaked in from the top through the cracks in the case leaked from somewhere it's probably This is this looks like electrolytic capacitor. This should be markings on it some place just not visible in the photograph

 

 

[HectorLooi]

That is probably not an electrolytic capacitor. It's most likely to be a paper in oil type, which is the best kind of capacitor in my opinion.

[JohnR725]

9 minutes ago, HectorLooi said:

oil type, which is the best kind of capacitor in my opinion

We won't know until we get the numbers but something leaked and all the other capacitors shouldn't have anything resembling a fluid.

 

3 hours ago, gpraceman said:

The big silver cylinder, if that is what you mean, doesn't have any signs of leakage.

Interesting I need to improve my reading skills it doesn't look like this leaked? So if this didn't leak what exactly was leaking?

 

[gpraceman]

27 minutes ago, JohnR725 said:

All of your mylar and paper capacitors are probably okay it's this one that I would be concerned about

Especially since something has leaked out from somewhere unless it had leaked in from the top through the cracks in the case leaked from somewhere it's probably This is this looks like electrolytic capacitor. This should be markings on it some place just not visible in the photograph

I'm not seeing any signs of leakage from that.  Here's some photos of it.

3 minutes ago, JohnR725 said:

We won't know until we get the numbers but something leaked and all the other capacitors shouldn't have anything resembling a fluid.

 

Interesting I need to improve my reading skills it doesn't look like this leaked? So if this didn't leak what exactly was leaking?

 

I am only seeing the oilyness on the 4 paper capacitors.  There's the smaller one that doesn't show that oilyness at all.

Edited December 22, 2023 by gpraceman

[JohnR725]

It reminds me of in one of the newer demagnetizer they're using a motor starting capacitor in the case of the one that I was looking at it is a solid capacitor but yours is probably filled with something. But it still brings up what exactly was leaking? Is there anything lurking underneath the circuit board or the whatever board that is?

 

[gpraceman]

6 minutes ago, JohnR725 said:

It reminds me of in one of the newer demagnetizer they're using a motor starting capacitor in the case of the one that I was looking at it is a solid capacitor but yours is probably filled with something. But it still brings up what exactly was leaking? Is there anything lurking underneath the circuit board or the whatever board that is?

Here's some side views.  Nothing else seems to have that oily substance on it except for a spot on the board.

Edited December 22, 2023 by gpraceman

[JohnR725]

Maybe what leaked came down from the top is in a box with other stuff and something gets spilled on it? Out of curiosity if you plug it in preferably when it's back in its case and push the button that what happens?

[gpraceman]

9 minutes ago, JohnR725 said:

Maybe what leaked came down from the top is in a box with other stuff and something gets spilled on it? Out of curiosity if you plug it in preferably when it's back in its case and push the button that what happens?

I did a quick operational test of it (in the case) with the cover screws placed in the white zone.  It caused the screws to jump due to the magnetic field pulse and the light flashed briefly.  That is all as should be expected.

There was only a bit of the oily stuff on the outside of the case and lots in the bottom of the case.  It rather seems that the stuff leaked out of the case (not into the case) as it tumbled around during shipping.

Edited December 22, 2023 by gpraceman

[Kalanag]

The silver Aerovox capacitor is not electrolytic most likely. Otherwise we wouldn‘t have two leads of the same color soldered on. So it should be safe.

 

EDIT:

The Aerovox 610 is an oil filled metallized polypropylene film capacitor as @HectorLooi mentioned already.

This is how this kind of demagnetizer works:

https://sound-au.com/clocks/demagnetiser.html

Edited December 22, 2023 by Kalanag

[LittleWatchShop]

7 hours ago, Kalanag said:

 

OK. I have restored several of the newer ones. I am certain they are all the same, essentially. I remove the caps, diodes, and resistors and toss them. The only thing I keep is the coil and the switch. I replaced the circuit completely with new components. If you search this forum, you will see the results of my work.

16 minutes ago, LittleWatchShop said:

OK. I have restored several of the newer ones. I am certain they are all the same, essentially. I remove the caps, diodes, and resistors and toss them. The only thing I keep is the coil and the switch. I replaced the circuit completely with new components. If you search this forum, you will see the results of my work.

 

I add a switch in mine because the 4uF cap is rated at 370V and the voltage multiplier puts continuous stress on it. You have to turn it on, wait about 10 seconds, then hit the demag button.

Edited December 22, 2023 by LittleWatchShop

[spectre6000]

@gpraceman I do this kind of stuff with fair frequency. My Fluke can measure capacitance. Let's get together, poke it a bit, make up a parts order with Digikey/Mouser, and we can bang that out in a hurry once the parts arrive. 

[gpraceman]

7 minutes ago, spectre6000 said:

@gpraceman I do this kind of stuff with fair frequency. My Fluke can measure capacitance. Let's get together, poke it a bit, make up a parts order with Digikey/Mouser, and we can bang that out in a hurry once the parts arrive. 

Sounds like a plan.  I'm not worried about measuring the current parts.  I'm inclined to just replace them with new more reliable components.  I've been reading that the paper variety capacitors are unreliable and should be replaced.  https://antiqueradio.org/recap.htm

[LittleWatchShop]

7 minutes ago, gpraceman said:

Sounds like a plan.  I'm not worried about measuring the current parts.  I'm inclined to just replace them with new more reliable components.  I've been reading that the paper variety capacitors are unreliable and should be replaced.  https://antiqueradio.org/recap.htm

I am happy to share my PCB layout if you want to replicate what I did. The  4 uF cap is labeled In my pictures. You can find it on the Internet.

[JackH]

The older capacitors were sometimes wax coated. Sometimes this coating can break down or melt.

[gpraceman]

6 minutes ago, LittleWatchShop said:

I am happy to share my PCB layout if you want to replicate what I did. The  4 uF cap is labeled In my pictures. You can find it on the Internet.

Do you have a layout for these L&R units?

[LittleWatchShop]

1 hour ago, gpraceman said:

Do you have a layout for these L&R units?

You mean schematic? Yes. That one has only a single coil, best I can tell.

https://mb.nawcc.org/threads/electronic-demagnetizer-repair.152142/

[gpraceman]

12 hours ago, LittleWatchShop said:

You mean schematic? Yes. That one has only a single coil, best I can tell.

https://mb.nawcc.org/threads/electronic-demagnetizer-repair.152142/

Thanks for the link.

15 hours ago, LittleWatchShop said:

OK. I have restored several of the newer ones. I am certain they are all the same, essentially. I remove the caps, diodes, and resistors and toss them. The only thing I keep is the coil and the switch. I replaced the circuit completely with new components. If you search this forum, you will see the results of my work.

I pulled off the top panel to see if there was any components hiding in there.  I don't see any diodes.  I see one large resistor and a couple of selenium rectifiers.  Any real reason to replace those?

I would think that there should be a fuse in there.

A power LED would be nice, but that would take away from the original look.

The switch sticks in the pressed position.  I'll see if I can get that working better or it'll end up on the replacement list.

 

[watchweasol]

Hi. LWS is correct in saying toss them and replace them , the paper ones are wax coated which breaks down , in any electronic re furbish they are removed and replaced by modern types