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0.00011 mf caps in bakelite blocks - Printable Version

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+--- Thread: 0.00011 mf caps in bakelite blocks (/showthread.php?tid=11143)


0.00011 mf caps in bakelite blocks - Kestas - 12-09-2014

I'm working on my model 116.  What is the concensus?  Are these 0.00011 mf capacitors replaced during restoration?  On one hand, that value suggests they're mica, which is usually left alone.  But on the other hand, why would these capacitors be potted in tar?  This suggests they are subject to degradation over time.

RE: 0.00011 mf caps in bakelite blocks - morzh - 12-09-2014

Inside backelites these are not mica.
Even if they are safe they have likely drifted, they are typically replaced.

RE: 0.00011 mf caps in bakelite blocks - AI2V - 12-09-2014

I've always used dipped mica 110pF caps here; they are cheap and perfectly suitable for the purpose. I buy at least 20 at a time. These are the caps that look like dark caramel candy.

RE: 0.00011 mf caps in bakelite blocks - Ron Ramirez - 12-09-2014

From all of the Philcos that have crossed my bench...and they number in the hundreds, I never bothered to count them...out of those that have 110 pF caps in bakelite block shells, the majority were small paper caps. I have encountered a few that had mica caps encapsulated in the tar, though...but as I said, the majority were paper.

As Pete (AI2V) said, dipped micas are excellent replacements for these. And, yes, I replace them as a matter of course in the Philco sets that use them.

RE: 0.00011 mf caps in bakelite blocks - Chuck Schwark - 12-10-2014

[Image: http://www.talonix.com/images/caps4/39pfDSM.jpg]

Looks like this.  Some are larger or smaller, depending 
on the capacitance and working voltage.

RE: 0.00011 mf caps in bakelite blocks - thirtiesradio - 12-23-2014

I just pulled 4 of those out of bakelite block shells last week and all 4 were paper. I used the dipped micas like in Chuck's photo.

RE: 0.00011 mf caps in bakelite blocks - Diverted - 01-13-2015

Another question, about the voltage rating on these caps; what were they originally? I would assume 500V micas would be fine?

RE: 0.00011 mf caps in bakelite blocks - codefox1 - 01-13-2015

Yes 500 volt micas will be OK.

RE: 0.00011 mf caps in bakelite blocks - Kestas - 01-13-2015

Can you double check that? The bakelite block I'm restoring is pn 8035-DG. Philco Service Bulletin No. 289 suggests these capacitors have a working voltage of 1200v.

RE: 0.00011 mf caps in bakelite blocks - Ron Ramirez - 01-13-2015

The maximum voltage these are going to see in the 2nd Detector circuit will be so low as to not be consequential, really.

You can use 1200 VDC caps if you wish. H**l, you can use 12,000 volt caps if you want to. But Codefox is correct, 500 WVDC caps are fine. Even 300 WVDC micas are fine. I use the 500 WVDC micas all of the time to replace these and I haven't had a single failure yet...and I do not expect to since they will only be exposed to somewhere between 0 and 10 volts in this circuit.

RE: 0.00011 mf caps in bakelite blocks - doug-5er - 01-19-2015

(12-09-2014, 04:19 PM)Kestas Wrote:  I'm working on my model 116.  What is the concensus?  Are these 0.00011 mf capacitors replaced during restoration?  On one hand, that value suggests they're mica, which is usually left alone.  But on the other hand, why would these capacitors be potted in tar?  This suggests they are subject to degradation over time.

Hi guys, I have run into the same bakelite block in my 38-2 as Kestas.Just a question would 0.0002 @ 630V be to much to use in place of the 0.00011? I have these on hand,but if I have to I will order the correct replacements.
Thanks 

RE: 0.00011 mf caps in bakelite blocks - Warren - 01-19-2015

Quote:Just a question would 0.0002 @ 630V be to much to use in place of the 0.00011?
You should stay within a 10 to 20 percent tolerance.

RE: 0.00011 mf caps in bakelite blocks - doug-5er - 01-20-2015

Just ordered up some 110pf caps so i should be good until I tackle THE BEAST my 38-116. After the 38-2, i
would hope things will be easier,still will be a challenge I know. Icon_thumbup but I'm up for it.

RE: 0.00011 mf caps in bakelite blocks - morzh - 01-20-2015

Oh...it's just a bunch of wires, glass an metal....nothing a man with a scredriver couldn't take on.

RE: 0.00011 mf caps in bakelite blocks - doug-5er - 01-20-2015

FIRE UP that soldering iron an lemme at it.Wait, I still have to finish the 38-2. Icon_biggrin