Replacing a Capacitor (Polaroid Processor)

[bvy]

As some of you may have seen in the classifieds, my Polaroid Processor exploded this morning and I was looking for a new one. But I'm wondering now if the unit can't be repaired.

Opening the unit reveals what appears to be a badly blown capacitor. After cleaning up the bits of paper and foil, I found a few loose wires that can easily be reconnected. The motor capacitor, of course, is shot.

I'm not great with electronics, but I know the basics and can use a soldering iron. Can this capacitor be replaced? And if so, what with, and what might I need to know about the actual repair?

Appreciate any help at all. Thanks.




Both pictures are after I cleaned up a bit (I blew all the debris out). I placed the guts of the blown capacitor in the power cord housing so it could be seen...

[Tin Can]

Well for starters, is there any identifying text on the bad one? You definitely need the correct one.

Then you find an online parts supply and buy one.

[bvy]

Thanks. It's labeled as a 0.8 uF 220 VAC capacitor. I checked several supply stores and can't find an exact match.

[jp]

If you find one with a higher voltage rating (in AC), that will suffice too.

[jcoldslabs]

Check post #5 in this thread:

http://www.largeformatphotography.in...-8x10-question

Jonathan

[Tin Can]

So the lesson is, change out this part BEFORE it blows and poisons your home.

To understand this comment you must read the other thread, Jonathon linked to.

[bvy]

Well, I don't plan to make a habit of this. Thanks for the link. Does this look like it will work?:
http://www.amazon.com/Metallized-Pol.../dp/B008DEZ6HM

[Tin Can]

You get 10 for that price!

I would try it. Must be better than what you have...

I buy almost everything from Amazon, pipe fittings lately as I couldn't find USA made ones at local HD. I had pipe leaks.

[Jody_S]

Capacitors can explode all on their own, but it's not common. They mostly just lose their capacitance and stop working. Those connected to a motor usually blow up when the motor shorts a winding. Just be prepared for the new one to blow up too, if you change it yourself (don't put your face in front of it when you turn it on).

[polyglot]

It's a motor-start capacitor, which needs to handle significant surge currents. You CANNOT replace it with that tiny polyester capacitor linked above because it will explode.

Secondly, are you SURE it's 0.8uF? It looks much larger than that and I think 8uF is more likely but could be misjudging the scale of the photo. Can you post a picture of the identifying marks on the cap? Anyway, search for "0.8uF motor capacitor" on eBay; they'll be mostly 450V but that's a good thing and means it will have a longer life due to less stress on the dielectric. Expect to pay about $1-$2/uF and buy one that has a physical form factor that matches your old one so it's easy to mount.

Note that this capacitor handles mains power, and contains enough energy to hurt you. Be careful installing it and make sure there is no way that the leads can get near to contacting any other metal items like the chassis.