Pot Roast Recipe

[Winky Dink]

Ingredients:
2 .001mfd, 1KV mica capacitors
2 .001 mfd, 630V poly capacitors
1 12,000 ohm, 2 watt resistor
1 20,000 ohm, 1/2 watt rotary potentiometer.

1. In a medum-size steel chassis, remove two .001 mfd, 1KV mica capacitors, and replace with two new .001 mfd, 630V capacitors.



2. Set power to "on."

3. When wax starts to drip off the 2-watt resistor, set the power to "off."



4. Voila! In less than two minutes you have roasted a pot!



I might try to repair it, but in the meantime I'm looking for a replacement. It's a 20K, 1/2-watt pot, and this is the most likely replacement I've found. Any other suggestions?



And while I'm here, I was looking for 1KV & up caps on Antique Electronic Supply, but got stymied by this:



Am I wrong, or are they mixing up uF, pF, and nF?

Thanks for your kind attention.

- Winky

[snelson903]

pot roast ,i like that. i would just replace it heat destorts things ,it might even have changed value now depending on how hot it got.

[Winky Dink]

It was actually 18.5Kohms before. After roasting it was linear 0-300 ohms, then a jump to 35K-47K.

[Eric H]

Are you sure those were Mica Caps?

Micas rarely need replaced, you should also replace Mica with Mica, not Film Caps and never use a lower voltage that what was in there.

Some caps that look like Mica aren't really, there's a way to tell by the color coding but I'd have to Google to find the chart.

Pretty sure the AES chart is a misprint, a 2.2 Mf 2000 volt Ceramic would be huge, you also don't want to use Ceramics to replace Film or Paper Caps in most applications.

2200Pf would only be 0.0022 Mf

Here's a Pf to Mf converter, it works both directions actually.
http://www.convertunits.com/from/mic...d/to/picofarad

[N2IXK]

Originally Posted by Eric H

a 2.2 Mf 2000 volt Ceramic would be huge

A 2.2 megafarad cap would be huge no matter what the dielectric was...

Even a 2.2 µF cap wouldn't be a ceramic disc.

[Winky Dink]

No, I'm not sure they were mica caps, and I've never before considered replacing ceramic or mica. This was a last-gasp attempt to correct a problem with the horizontal hold by replacing every component that I couldn't verify for certain. The lower voltage rating was my mistake--I just forgot. As soon as I turned on the set I noticed that I'd lost some horizontal size, took a few seconds playing with controls before I noticed the wax melting on the resistor--that's when I remembered the original caps were rated 1 KV.
- Winky

[Dude111]

I like easy recipes like this!!

Now to get the stuff to make it